Category Archives: Quantum Physics

If you know anything about black holes, it may come as a surprise to learn that theres actually one lurking at the center of our galaxy. It was uncovered by UCLA astrophysicist Andrea Ghez, and in 2020 shewon a Nobel Prizefor this discovery. But how do you go about finding something that emits no light? How do you see the unseeable?

In this episode, Ghez explains how she proved this supermassive black hole was hiding in the Milky Way and answers all our pressing questions like, including: Are we being sucked into this monster? And could researching it prove Einsteins theory of relativity is actuallywrong?

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Paul Rand: Theres a monster lurking at the center of our galaxy.

Tape: Its a monster, all right.

Tape: A rip in the very fabric of space and time.

Paul Rand: Its been there your whole life, and maybe as long as the life of our galaxy itself.

Andrea Ghez: Well, its a million to a billion times the mass of the Sun, so you might call it monstrous in its mass.

Paul Rand: That is Andrea Ghez. Shes a professor of physics and astronomy at UCLA, and a graduate of the University of Chicago Laboratory Schools. And, last year, she won the Nobel Prize in physics for proving that, at the center of the Milky Way, is a black hole.

Tape: This years prize is about the darkest secrets of the universe.

Paul Rand: And not just any black hole, but a supermassive one.

Andrea Ghez: Today, we think that most, if not all, galaxies harbors black holes at their centers, and that this black hole plays a really essential part in both the formation of the galaxy, our own is the Milky Way, and the evolution of galaxies, which are really the fundamental building blocks of our universe.

Paul Rand: If youve seen or read any sci-fi, your first reaction is probably to fear that were being sucked into this black hole.

Andrea Ghez: So black holes have this very bad reputation of being cosmic vacuum cleaners. That is an unfortunate, and incorrect, conceptualization. For the most part, most things that are nearby it will happily orbit the black hole the same way that the planets orbit the Sun. That you dont get the pulling, or dragging in, of objects.

Paul Rand: The idea that theres something at the center of our galaxy that you not only cant see, but that we dont understand, is terrifying. But it bothers scientists on a fundamental level. Their job is to find things out, and not only do they not know what happens inside black holes, but they think if they can find the answer, it may hold the keys to understanding all of space and time.

Andrea Ghez: Black holes are such interesting objects because theyre some of the most simple objects that we have in our universe, and yet theyre the most complex because we dont have the physics to describe them.

Paul Rand: From the University of Chicago podcast network, this is Big Brains: a podcast about the pioneering research, and pivotal breakthroughs that are reshaping our world. On this episode, the monster black hole that lurks at the center of our galaxy, and the quest to prove it exists.

Paul Rand: Im your host, Paul Rand.

Paul Rand: Andrea Ghez may have won the Nobel Prize in 2020, but shes been thinking about space ever since she was four years old.

Andrea Ghez: Oh, gosh. The scale of the universe was really what caught my fantasy. Or, sorry, thats what caught my fancy. And my fantasy. I think I was so ... I think troubled probably was the first place.

Paul Rand: Oh, interesting.

Andrea Ghez: And it was that early recognition that youre insignificant on the scale of the universe, both in terms of space ...

Paul Rand: Which is great when youre four, isnt it?

Andrea Ghez: Yeah. A little terrifying. I mean, I really distinctly remember this. It kept me up at night. And all these things that, before you have the mathematical tools, our every day experience dont prepare us for thinking about, well what does it mean to talk about the beginning and end of time, or the edge of space? I mean, thats how you think about your world at age four.

Paul Rand: Right. Right. Of course.

Andrea Ghez: So, I think those were the things that stuck with me, and stuck with me for a really long time.

Paul Rand: And theres almost nothing more terrifying out in space than black holes, so naturally thats where Ghez was drawn. But not all black holes are created equal. Some stand out more than others.

Andrea Ghez: There are two forms of black holes that we think exist astrophysical, and theyre distinguished based on mass, and we also think that theyre distinguished based on how they were formed.

Paul Rand: The first is probably what youre thinking of: a star, kind of like our Sun, but bigger, that collapsed at the end of its life.

Andrea Ghez: So, theory predicts that stars that start their lives off with a lot of mass, much more massive than the Sun, they should end their life as stellar mass black holes. And they are roughly ten times the mass of the Sun, on order of ten. Okay. So we predicted them theoretically, and then we found them observationally. That was about, oh gosh, half a century ago.

Paul Rand: Then theres the other kind, and they made those look like small potatoes.

Andrea Ghez: The supermassive black holes, by their name you know that theyre much more massive, so theyre roughly a million to a billion times the mass of the Sun.

Paul Rand: And supermassive black holes are really Ghezs specialty. She was awarded the Nobel Prize in 2020 for proving that one is at the center of the Milky Way.

Andrea Ghez: So observations of the centers of galaxies revealed phenomena that werent easily explained by other things that we recognized. And that lead people, those observations, lead people to suggest that they could exist. And thats whats such a big deal about this result, is that weve demonstrated that this other type of black hole, the ones that are a million to a billion and that reside at the center of galaxies, exist.

Paul Rand: But wait a minute. Black holes are called black holes because we actually cant see them.

Tape: Getting towards blackness.

Paul Rand: They emit no light. So how do you prove something exists if you cant see it?

Tape: Its all blackness.

Paul Rand: To see the unseeable, Ghez has an A star near the black hole.

Andrea Ghez: So SO-2 is my favorite star in the universe.

Paul Rand: Okay. Thats quite a designation. Why is it your favorite?

Andrea Ghez: Its my favorite because its the one that has the most capacity to tell us what lurks at the center of the galaxy.

Paul Rand: What Ghez did was take very good measurements of the things you can see, like the stars nearby, and she could see they were orbiting something invisible, but very big.

Andrea Ghez: How long does it take these stars to orbit whatevers at the center? So SO-2, my favorite, goes around the center of the galaxy every 16 years. So once we could figure out both the size of the orbit, like how far away it gets, the shape of the orbit, and the time scale of the orbit, we can figure out the mass thats driving its motion. So we, at that point, could say it is four million times the mass of the Sun inside a region that corresponds to the scale of our solar system, and that is the proof of a black hole.

Paul Rand: So what came first in the realm, the galaxy or the black hole?

Andrea Ghez: Well, thats a great question. In fact, its kind of like the chicken or the egg question.

Paul Rand: Uh huh.

Andrea Ghez: And for many years, people didnt know, and, in fact, in the early years of this research, thats how it was phrased. Which came first, the galaxy or the black? And, in fact, as a community we had explanations that could support one or the other, and today we, I think, shifted to understand that thats even the wrong question. That the mass of the central part of the galaxy seems to be always correlated with the mass of the black hole, and the scale ... the size, the scales are so different, that suggests that whatever formed one had to form the other synergistically, and that theres some feedback mechanism that keeps that relationship fixed over the lifetime of the galaxy. So it means that theres something really important in terms of the controlling feature, or that relationship between the black hole and the galaxy. So they formed together.

Andrea Ghez: But, in fact, because we think that theres such an intimate relationship between the supermassive black holes and their host galaxies, the supermassive black holes are found at the very center of these galaxies, we think that they formed from the process that gave rise to the galaxy in the first place.

Andrea Ghez: So if you think about the universe, which started off as an incredibly simple place: it was big, empty, kind of boring.

Paul Rand: Little dark.

Andrea Ghez: A little dark. Very dark. But there were fluctuations of densities, of very simple gas, that collapsed. So it was a collapsed process that led to the formation of galaxies. So in some sense its very similar to the formation of stars, but on a much bigger scale.

Paul Rand: So then is the idea as you describe it that every planet, every star, eventually becomes a black hole?

Andrea Ghez: Oh no. Actually, we have to be super careful about this.

Paul Rand: Okay.

Andrea Ghez: So its only the most massive stars in which we get ... you can describe it as a balancing of forces ...

Paul Rand: Mm-hmm (affirmative).

Andrea Ghez: ... or ... and here I want to be careful. Ill describe it as a tug-of-war for conceptualization. So you have gravity on one side, and at the other side you have other forms of forces. Black holes form when gravity wins over anything that can be put on the other side.

Paul Rand: Okay.

Andrea Ghez: So the Sun, theres not enough gravitational force associated with that mass for the Sun to overcome ... effectively, its actually the fact that the electrons dont like each other, or dont like to share the same space. So that creates a force that counteracts gravity, so you have to get to much more massive objects to overcome that force and other forces that can get in the way of that collapse. So we think that stars in our own galaxy that start their lives off with more mass than 30 times the mass of the Sun will end up as stellarmass black holes. In other words, youve created that environment in which gravity wins.

Paul Rand: Youve also talked about describing this monster, and I think I remember this, where you talked about it as having an unusually large meal, maybe playing this analogy out a little bit more. So why the nightmares are there are beginning to come up a little bit more. Does that still hold as you think about this description? What did that mean as you said it?

Andrea Ghez: So its interesting in terms of talking about things where were really at the edge of, or the frontier of, our knowledge. How do you create these analogies that work?

Paul Rand: Yes.

Andrea Ghez: So if we go back to thinking about what observations made us think about the existence of supermassive black holes, one of those observations was the emission of a tremendous amount of light at the center of galaxies that was unlike anything emitted by stars or gas. And today we think that thats from matter falling onto the black hole. So the way we think about those galaxies that we first looked at to say that there were supermassive black holes are called active galactic nuclei. So in other words, theyre galaxies where their nuclei, or centers, are active. Thats a lot of mission. And we say, well thats probably lots of matter falling onto the black hole, or falling through the event horizon, the last point that light can escape, onto the black hole. So thats where I like to make that analogy, that these are black holes or galaxies that are having a Thanksgiving feast, but theyre dining on a lot of matter thats just outside the event horizon. In other words, available, close enough to the event horizon to be pulled in. So the giant dining feast analogy works really well.

Andrea Ghez: And its useful to make that analogy when youre talking about our galaxy, because our galaxy is very quiet in comparison to these active galactic nuclei. There is a source that looks like a very wimpy version of active galactic nuclei in terms of its characteristics, but its wimpy. So you can talk about ... its like our galaxy, if you think that thats the same phenomena, is having a snack.

Paul Rand: And do they ever end, black holes in general, ending? Do they stop?

Andrea Ghez: Well, thats also an interesting question that forces one to think about the ultimate evolution of the universe.

Paul Rand: Okay.

Andrea Ghez: So our universe has been around for roughly 14 billion years. That seems like a long time scale to us.

Paul Rand: It does.

Andrea Ghez: But the universe is going to go on for much longer times scales, if you just ... these things ... all the objects in our universe live for a long time, but black holes live for a really long time. Theres a wonderful book by Fred Adams called The Dark Ages, which just runs, basically, a simulation of the universe out to its absurd endpoints, and what you have is a very dark place, and hence the name, and a lot of black holes just hanging around.

Paul Rand: Okay. I think Ive been in a bar like that before.

Paul Rand: After the break, Einstein, a black hole, and quantum mechanics walk into a bar. Well talk about what happens next.

Paul Rand: Hello Big Brains listeners. The University of Chicago podcast network is excited to announce the launch of a new show. Its called Entitled, and its about human rights. Co hosted by lawyers and Uchicago law school professors Claudia Flores and Tom Ginsburg, Entitled explores the stories around why rights matter, and whats the matter with rights.

Paul Rand: The best thing about black holes is that their possibilities are literally infinite. A black hole is like a playground for physicists. Even how things circle around this black hole can tell Ghez secrets about the universe.

Andrea Ghez: So theyre quite simple, and yet we dont have the physics to describe them, and so they represent the frontier of our knowledge, and in particular our ability to make our description of the physical world thats small, which is the world of quantum mechanics, work together with the description of the world that describes how gravity works. So thats the realm of general relativity, what Einstein is so famous for. So today, we dont know how to make those two fields meet, and while black holes are a prediction, or an expected outcome of general relativity, we cant describe the details because you have to understand how to make that description of quantum mechanics work with the description of general relativity.

Andrea Ghez: So, in a sense, theyre really exciting, because they say if you want to understand physics, from a pure physics perspective, push our understanding of physics forward, these are objects that are incredibly exciting because they represent where that mixing happens.

Paul Rand: What Ghez wants to test using black holes isnt just some obscure theories, but the fundamental natures of our universe.

Andrea Ghez: Gravity is one of the four fundamental forces of our universe, but in fact, its the least tested of the four fundamental forces. So weve been able to get into this new era of asking, well how does gravity work near a supermassive black hole? Does gravity work in the way, in this region, outside the event horizon, in the way that Einstein predicted? And so we were able to do the first set of those observations, or measurements, in 2018.

Paul Rand: But theres been some discussions about this idea of co-mingling of space and time, and can you explain, when that phrase is used, what that refers to?

Andrea Ghez: Absolutely. I mean, its really one of the most key elements of Einsteins revolution on the description of how does gravity work. So Newton had a great description that we used for many, many, many years, and in that description theres no connection between space and time. So what Einstein is effectively saying is that space and time, how we think about space and time, are no longer independent when you get into a very strong gravitational field. So in the case of the black hole at the center of our galaxy, out at large distances, you can actually use Newtons laws of gravity to describe some of these orbits. But for the closest star, SO-2 in particular, as it goes through closest approach, we can now actually see and verify how Einstein has modified that theory of gravity to work in strong gravitational fields, which is that co-mingling.

Andrea Ghez: And, in fact, if you go into science museums, you often see the gravity well, that funnel where they encourage you to roll down a quarter or something that goes into the black hole, and what that visualization is supposed to help us with is its pretending that the surface at the top is space. So its collapsed one dimension of space, so thats just two dimensional space, and its using the third dimension to describe time. So theres this deformation as you go towards the center.

Paul Rand: And lets play out a little bit more as youre digging into Einstein and, at least as youre talking about the theory of relativity, youve said that it appears that Einsteins right, at least for now. And I wonder if you can explain that a little bit more, and does that mean you think its going to be proven wrong?

Andrea Ghez: So when I said before that Einstein is right, at least for now, it means that our ability to see these effects increases with time. So in other words, as you continue to make these measurements, your understanding of how gravity works improves. So, the other joke I like to make: its like a bottle of fine wine. It just keeps improving with time.

Andrea Ghez: So yes, its passed the test today, but the test is going to become more stringent as we go forward in time, and there are future tests that are emerging. So, in fact, as we make our way, or as SO-2, as we see it, is making its way towards its furthest approach, other tests, which are in some sense more fundamental, how the object itself moves through space and time rather than photons moving through space and time, are emerging. So were just now making that last push to really see how this star and others are moving. And once again, its a super exciting phase of the experiment, because were starting to see signals that we couldnt see before, and youre at that stage in the experiment where you have to ask is what youre seeing physics, or is what youre seeing the inaccuracies in how youve analyzed the data? In other words, as your ability to make the measurements improve, you have to be very careful about what we call systematic errors creeping in.

Andrea Ghez: So how do you ... the visual I have in my head when I think about what were doing today, its like going around the cars and kicking the tires, like is what we do robust enough to claim that what we see if true physics versus some mistake?

Paul Rand: Andrea Ghez is one of only four women to ever win a Nobel Prize in physics.

Andrea Ghez: In all honesty, lets look at who was the first: Marie Curie. She set the bar so incredibly high. She not only won one Nobel Prize, she won two, and her daughter won a Nobel Prize. So I remember when I was young reading biographies of Marie Curie, so she was already an important figure in terms of my understanding that it was possible.

Paul Rand: When shes not talking about black holes, Ghez advocates for more women entering the sciences, and she hopes her Nobel Prize may inspire even more women.

Andrea Ghez: What I can say is that, from first-hand knowledge, I think that having strong and visible role models is super important. So if I think about my own evolution, my very first science teacher was at the University of Chicago in a chemistry class, and what I didnt understand at the time was how fortunate I was to have, already, a model of a woman who was a scientist. I didnt question it in high school, why should I? It was just there.

Andrea Ghez: She actually did something that was really important. At the time I remember applying to colleges, and I had decided that I really wanted to go to MIT, and somebody said, well, MIT doesnt accept girls, and I remember going and talking to this science teacher, and she was great. She just said, well, whats the worst thing that can happen? They say no. So, one, it was clearly the place I was going to look for the advice. Clearly there was already, early, this ... I mean, youre starting to feel that discouragement. So even though I had the good fortunate of being in a family, an environment, in a school environment where there was tremendous support, somehow culturally, theres still that skepticism. If you just look at all our images of scientists, they tend to be men.

Andrea Ghez: And, in fact, I think thats why Star Trek was so important for my generation, is that there were women on the space trap. So I really guess Ive really come to appreciate how important it is to have women role models, so at MIT and then at Cal Tech as a grad student, there were very few women scientists, and I can remember there were moments where I just ... actually, the way I used to think about it is Im in the wrong playground. You sit in these classes, especially in physics, there would be 100 people, and thered be four women, and you just knew something ... its like, do you have the fortitude, passion? I mean, for me, it was always, yeah, this is what I like. Why shouldnt I be able to do it? But I think its what also makes me so interested in teaching at the undergrad level. To teach the earliest classes, where you can help change the notion, just from a ... its almost that unconscious bias perspective. How do you think about a scientist? What do they look like?

Andrea Ghez: So receiving the Nobel Prize, and having this highlighted as the fourth time, it just makes me realize that thats a really important visibility piece, because, again, it changes the notion.

Paul Rand: Of course, diversity is important in every field, but Im wondering, as you think about your field, and in terms of the disparity that were talking about, what disadvantages it actually presents that greater intermingling could actually be beneficial to science itself.

Andrea Ghez: Its interesting to think about. I mean, the science itself doesnt care what gender you are. Actually, it doesnt even care about your existence. Were talking about scales that are so much larger than we are, its a very humbling field.

Andrea Ghez: I guess the things that have come to mind as I get older is theres something very liberating, actually, about being ... in terms of suggesting new ideas and being, maybe, challenging the status quo in terms of how people think. Theres some social costs for doing that. So if youre in the majority, theres more social cost for suggesting new ideas. If youre already on the outside, I think theres less cost, and it maybe gives you an opportunity to not only think differently, but also speak differently.

Andrea Ghez: What I really think, and I feel strongly about this, is that diversity of thought is really important, and, in fact, its why competition is so important. So, another aspect of this prize is that both I and my competitor were awarded the prize, and its also given a wonderful opportunity to talk about the benefit, not only of competition, but also the idea that two different points of view is really valuable. I mean, I think that weve not only kept each other on our toes, but we often think quite different about the work.

Andrea Ghez: You learn. I mean, you learn ... I mean, while these groups are independent, theyre not ... the fact that were all part of a community, which means that were constantly presenting our results at meetings or publishing our result means that you are learning from each other. So theres been this interesting ratcheting up of understanding. And, in fact, I think the work has gotten so much further for the existence of these two groups. So I think that really highlights how much further you can get when you have different modes of thought, whether or not that comes from your background, your training, your just overall experiences. I think science will always benefit from multiplicity of viewpoints.

Paul Rand: One final question that Im wondering is, were coming out of a period where the climate reports are more precarious by the day. Youre out in California where the wildfires and other ramifications of climate change are really starting to ravish the earth in a lot of different ways. How in the world that you operate in, do you look at what is happening into our world, and either gain some comfort out of that, gain a different perspective on that, or it doesnt impact you in your thinking in any way?

Andrea Ghez: Oh I think its hard to be human and not have this impact your thinking. We as humans are having incredible impact on our environment and our ability to survive. I, personally, think about this from the point of view of how important it is for people to understand what scientists have to say about the status of our climate, the status of our global health, and this is where I think astronomy plays a really important role because I like to think of astronomy as the gateway science. It is a science that so many people have a fundamental curiosity about. It inspires us to think about this amazing, fascinating universe that we live in. Its hard not to be engaged by those notions from a very early age.

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Big Brains podcast: Unlocking the secrets of black holes - UChicago News

Quantum mechanics explains how the universe works at a scale smaller than atoms. It is also called quantum physics or quantum theory. Mechanics is the part of physics that explains how things move and quantum is the Latin word for 'how much'. A quantum of energy is the least amount possible (or the least extra amount), and quantum mechanics describes how that energy moves or interacts.

Atoms used to be considered the smallest building blocks of matter, but modern science has shown that there are even smaller particles, like protons, neutrons and electrons. Quantum mechanics describes how the particles that make up atoms work.

Quantum mechanics also tells us how electromagnetic waves (like light) work. Waveparticle duality means that particles behave like waves and waves behave like particles. (They are not two kinds of thing, they are something like both: this is their duality.) Much of modern physics and chemistry can be described and understood using the mathematical rules of quantum mechanics.

The mathematics used to study subatomic particles and electromagnetic waves is very complex because they act in very strange ways.

Photons are particles that are point-sized, tinier than atoms. Photons are like "packets" or packages of energy. Light sources such as candles or lasers produce light in bits called photons.

The more photons a lamp produces, the brighter the light. Light is a form of energy that behaves like the waves in water or radio waves. The distance between the top of one wave and the top of the next wave is called a 'wavelength'. Each photon carries a certain amount, or 'quantum', of energy depending on its wavelength.

A light's color depends on its wavelength. The color violet (the bottom or innermost color of the rainbow) has a wavelength of about 400nm ("nanometers") which is 0.00004 centimeters or 0.000016 inches. Photons with wavelengths of 10-400nm are called ultraviolet (or UV) light. Such light cannot be seen by the human eye. On the other end of the spectrum, red light is about 700nm. Infrared light is about 700nm to 300,000nm. Human eyes are not sensitive to infrared light either.

Wavelengths are not always so small. Radio waves have longer wavelengths. The wavelengths for an FM radio can be several meters in length (for example, stations transmitting on 99.5 FM are emitting radio energy with a wavelength of about 3 meters, which is about 10 feet). Each photon has a certain amount of energy related to its wavelength. The shorter the wavelength of a photon, the greater its energy. For example, an ultraviolet photon has more energy than an infrared photon.

Wavelength and frequency (the number of times the wave crests per second) are inversely proportional, which means a longer wavelength will have a lower frequency, and vice versa. If the color of the light is infrared (lower in frequency than red light), each photon can heat up what it hits. So, if a strong infrared lamp (a heat lamp) is pointed at a person, that person will feel warm, or even hot, because of the energy stored in the many photons. The surface of the infrared lamp may even get hot enough to burn someone who may touch it.Humans cannot see infrared light, but we can feel the radiation in the form of heat. For example, a person walking by a brick building that has been heated by the sun will feel heat from the building without having to touch it.

The mathematical equations of quantum mechanics are abstract, which means it is impossible to know the exact physical properties of a particle (like its position or momentum) for sure. Instead, a mathematical function called the wavefunction provides information about the probability with which a particle has a given property. For example, the wavefunction can tell you what the probability is that a particle can be found in a certain location, but it can't tell you where it is for sure. Because of this uncertainty and other factors, you cannot use classical mechanics (the physics that describe how large objects move) to predict the motion of quantum particles.

Ultraviolet light is higher in frequency than violet light, such that it is not even in the visible light range. Each photon in the ultraviolet range has a lot of energy, enough to hurt skin cells and cause a sunburn. In fact, most forms of sunburn are not caused by heat; they are caused by the high energy of the sun's UV rays damaging your skin cells. Even higher frequencies of light (or electromagnetic radiation) can penetrate deeper into the body and cause even more damage. X-rays have so much energy that they can go deep into the human body and kill cells. Humans cannot see or feel ultraviolet light or x-rays. They may only know they have been under such high frequency light when they get a radiation burn. Areas where it is important to kill germs often use ultraviolet lamps to destroy bacteria, fungi, etc. X-rays are sometimes used to kill cancer cells.

Quantum mechanics started when it was discovered that if a particle has a certain frequency, it must also have a certain amount of energy. Energy is proportional to frequency (Ef). The higher the frequency, the more energy a photon has, and the more damage it can do. Quantum mechanics later grew to explain the internal structure of atoms. Quantum mechanics also explains the way that a photon can interfere with itself, and many other things never imagined in classical physics.

Max Planck discovered the relationship between frequency and energy. Nobody before had ever guessed that frequency is directly proportional to energy (this means that as one of them doubles, the other does, too). Under what are called natural units, then the number representing the frequency of a photon would also represent its energy. The equation would then be:

meaning energy equals frequency.

But the way physics grew, there was no natural connection between the units that were used to measure energy and the units commonly used to measure time (and therefore frequency). So the formula that Planck worked out to make the numbers all come out right was:

or, energy equals h times frequency. This h is a number called Planck's constant after its discoverer.

Quantum mechanics is based on the knowledge that a photon of a certain frequency means a photon of a certain amount of energy. Besides that relationship, a specific kind of atom can only give off certain frequencies of radiation, so it can also only give off photons that have certain amounts of energy.

Isaac Newton thought that light was made of very small things that we would now call particles (he referred to them as "Corpuscles"). Christiaan Huygens thought that light was made of waves. Scientists thought that a thing cannot be a particle and a wave at the same time.

Scientists did experiments to find out whether light was made of particles or waves. They found out that both ideas were right light was somehow both waves and particles. The Double-slit experiment performed by Thomas Young showed that light must act like a wave. The Photoelectric effect discovered by Albert Einstein proved that light had to act like particles that carried specific amounts of energy, and that the energies were linked to their frequencies. This experimental result is called the "wave-particle duality" in quantum mechanics. Later, physicists found out that everything behaves both like a wave and like a particle, not just light. However, this effect is much smaller in large objects.

Here are some of the people who discovered the basic parts of quantum mechanics: Max Planck, Albert Einstein, Satyendra Nath Bose, Niels Bohr, Louis de Broglie, Max Born, Paul Dirac, Werner Heisenberg, Wolfgang Pauli, Erwin Schrdinger, John von Neumann, and Richard Feynman. They did their work in the first half of the 20th century.

Quantum mechanics formulae and ideas were made to explain the light that comes from glowing hydrogen. The quantum theory of the atom also had to explain why the electron stays in its orbit, which other ideas were not able to explain. It followed from the older ideas that the electron would have to fall in to the center of the atom because it starts out being kept in orbit by its own energy, but it would quickly lose its energy as it revolves in its orbit. (This is because electrons and other charged particles were known to emit light and lose energy when they changed speed or turned.)

Hydrogen lamps work like neon lights, but neon lights have their own unique group of colors (and frequencies) of light. Scientists learned that they could identify all elements by the light colors they produce. They just could not figure out how the frequencies were determined.

Then, a Swiss mathematician named Johann Balmer figured out an equation that told what (lambda, for wave length) would be:

where B is a number that Balmer determined to be equal to 364.56nm.

This equation only worked for the visible light from a hydrogen lamp. But later, the equation was made more general:

where R is the Rydberg constant, equal to 0.0110nm1, and n must be greater than m.

Putting in different numbers for m and n, it is easy to predict frequencies for many types of light (ultraviolet, visible, and infared). To see how this works, go to Hyperphysics and go down past the middle of the page. (Use H = 1 for hydrogen.)

In 1908, Walter Ritz made the Ritz combination principle that shows how certain gaps between frequencies keep repeating themselves. This turned out to be important to Werner Heisenberg several years later.

In 1905, Albert Einstein used Planck's idea to show that a beam of light is made up of a stream of particles called photons. The energy of each photon depends on its frequency. Einstein's idea is the beginning of the idea in quantum mechanics that all subatomic particles like electrons, protons, neutrons, and others are both waves and particles at the same time. (See picture of atom with the electron as waves at atom.) This led to a theory about subatomic particles and electromagnetic waves called wave-particle duality. This is where particles and waves were neither one nor the other, but had certain properties of both.

In 1913, Niels Bohr came up with the idea that electrons could only take up certain orbits around the nucleus of an atom. Under Bohr's theory, the numbers called m and n in the equation above could represent orbits. Bohr's theory said electrons could begin in some orbit m and end up in some orbit n, or an electron could begin in some orbit n and end up in some orbit m so if a photon hits an electron, its energy will be absorbed, and the electron will move to a higher orbit because of that extra energy. Under Bohr's theory, if an electron falls from a higher orbit to a lower orbit, then it will have to give up energy in the form of a photon. The energy of the photon will equal the energy difference between the two orbits, and the energy of a photon makes it have a certain frequency and color. Bohr's theory provided a good explanation of many aspects of subatomic phenomena, but failed to answer why each of the colors of light produced by glowing hydrogen (and by glowing neon or any other element) has a brightness of its own, and the brightness differences are always the same for each element.

By the time Niels Bohr came out with his theory, most things about the light produced by a hydrogen lamp were known, but scientists still could not explain the brightness of each of the lines produced by glowing hydrogen.

Werner Heisenberg took on the job of explaining the brightness or "intensity" of each line. He could not use any simple rule like the one Balmer had come up with. He had to use the very difficult math of classical physics that figures everything out in terms of things like the mass (weight) of an electron, the charge (static electric strength) of an electron, and other tiny quantities. Classical physics already had answers for the brightness of the bands of color that a hydrogen lamp produces, but the classical theory said that there should be a continuous rainbow, and not four separate color bands. Heisenberg's explanation is:

There is some law that says what frequencies of light glowing hydrogen will produce. It has to predict spaced-out frequencies when the electrons involved are moving between orbits close to the nucleus (center) of the atom, but it also has to predict that the frequencies will get closer and closer together as we look at what the electron does in moving between orbits farther and farther out. It will also predict that the intensity differences between frequencies get closer and closer together as we go out. Where classical physics already gives the right answers by one set of equations the new physics has to give the same answers but by different equations.

Classical physics uses the methods of the French mathematician Fourier to make a math picture of the physical world, and it uses collections of smooth curves that go together to make one smooth curve that gives, in this case, intensities for light of all frequencies from some light. But it is not right because that smooth curve only appears at higher frequencies. At lower frequencies, there are always isolated points and nothing connects the dots. So, to make a map of the real world, Heisenberg had to make a big change. He had to do something to pick out only the numbers that would match what was seen in nature. Sometimes people say he "guessed" these equations, but he was not making blind guesses. He found what he needed. The numbers that he calculated would put dots on a graph, but there would be no line drawn between the dots. And making one "graph" just of dots for every set of calculations would have wasted lots of paper and not have gotten anything done. Heisenberg found a way to efficiently predict the intensities for different frequencies and to organize that information in a helpful way.

Just using the empirical rule given above, the one that Balmer got started and Rydberg improved, we can see how to get one set of numbers that would help Heisenberg get the kind of picture that he wanted:

The rule says that when the electron moves from one orbit to another it either gains or loses energy, depending on whether it is getting farther from the center or nearer to it. So we can put these orbits or energy levels in as headings along the top and the side of a grid. For historical reasons the lowest orbit is called n, and the next orbit out is called n - a, then comes n - b, and so forth. It is confusing that they used negative numbers when the electrons were actually gaining energy, but that is just the way it is.

Since the Rydberg rule gives us frequencies, we can use that rule to put in numbers depending on where the electron goes. If the electron starts at n and ends up at n, then it has not really gone anywhere, so it did not gain energy and it did not lose energy. So the frequency is 0. If the electron starts at n-a and ends up at n, then it has fallen from a higher orbit to a lower orbit. If it does so then it loses energy, and the energy it loses shows up as a photon. The photon has a certain amount of energy, e, and that is related to a certain frequency f by the equation e = h f. So we know that a certain change of orbit is going to produce a certain frequency of light, f. If the electron starts at n and ends up at n - a, that means it has gone from a lower orbit to a higher orbit. That only happens when a photon of a certain frequency and energy comes in from the outside, is absorbed by the electron and gives it its energy, and that is what makes the electron go out to a higher orbit. So, to keep everything making sense, we write that frequency as a negative number. There was a photon with a certain frequency and now it has been taken away.

So we can make a grid like this, where f(ab) means the frequency involved when an electron goes from energy state (orbit) b to energy state a (Again, sequences look backwards, but that is the way they were originally written.):

Grid of f

Heisenberg did not make the grids like this. He just did the math that would let him get the intensities he was looking for. But to do that he had to multiply two amplitudes (how high a wave measures) to work out the intensity. (In classical physics, intensity equals amplitude squared.) He made an odd-looking equation to handle this problem, wrote out the rest of his paper, handed it to his boss, and went on vacation. Dr. Born looked at his funny equation and it seemed a little crazy. He must have wondered, "Why did Heisenberg give me this strange thing? Why does he have to do it this way?" Then he realized that he was looking at a blueprint for something he already knew very well. He was used to calling the grid or table that we could write by doing, for instance, all the math for frequencies, a matrix. And Heisenberg's weird equation was a rule for multiplying two of them together. Max Born was a very, very good mathematician. He knew that since the two matrices (grids) being multiplied represented different things (like position (x,y,z) and momentum (mv), for instance), then when you multiply the first matrix by the second you get one answer and when you multiply the second matrix by the first matrix you get another answer. Even though he did not know about matrix math, Heisenberg already saw this "different answers" problem and it had bothered him. But Dr. Born was such a good mathematician that he saw that the difference between the first matrix multiplication and the second matrix multiplication was always going to involve Planck's constant, h, multiplied by the square root of negative one, i. So within a few days of Heisenberg's discovery they already had the basic math for what Heisenberg liked to call the "indeterminacy principle." By "indeterminate" Heisenberg meant that something like an electron is just not pinned down until it gets pinned down. It is a little like a jellyfish that is always squishing around and cannot be "in one place" unless you kill it. Later, people got in the habit of calling it "Heisenberg's uncertainty principle," which made many people make the mistake of thinking that electrons and things like that are really "somewhere" but we are just uncertain about it in our own minds. That idea is wrong. It is not what Heisenberg was talking about. Having trouble measuring something is a problem, but it is not the problem Heisenberg was talking about.

Heisenberg's idea is very hard to grasp, but we can make it clearer with an example. First, we will start calling these grids "matrices," because we will soon need to talk about matrix multiplication.

Suppose that we start with two kinds of measurements, position (q) and momentum (p). In 1925, Heisenberg wrote an equation like this one:

He did not know it, but this equation gives a blueprint for writing out two matrices (grids) and for multiplying them. The rules for multiplying one matrix by another are a little messy, but here are the two matrices according to the blueprint, and then their product:

Matrix of p

Matrix of q

The matrix for the product of the above two matrices as specified by the relevant equation in Heisenberg's 1925 paper is:

Where:

A=p(nn-a)*q(n-an-b)+p(nn-b)*q(n-bn-b)+p(nn-c)*q(n-cn-b)+.....

B=p(n-an-a)*q(n-an-c)+p(n-an-b)*q(n-bn-c)+p(n-an-c)*q(n-cn-c)+.....

C=p(n-bn-a)*q(n-an-d)+p(n-bn-b)*q(n-bn-d)+p(n-bn-c)*q(n-dn-d)+.....

and so forth.

If the matrices were reversed, the following values would result:

A=q(nn-a)*p(n-an-b)+q(nn-b)*p(n-bn-b)+q(nn-c)*p(n-cn-b)+.....B=q(n-an-a)*p(n-an-c)+q(n-an-b)*p(n-bn-c)+q(n-an-c)*p(n-cn-c)+.....C=q(n-bn-a)*p(n-an-d)+q(n-bn-b)*p(n-bn-d)+q(n-bn-c)*p(n-dn-d)+.....

and so forth.

Note how changing the order of multiplication changes the numbers, step by step, that are actually multiplied.

The work of Werner Heisenberg seemed to break a log jam. Very soon, many different other ways of explaining things came from people such as Louis de Broglie, Max Born, Paul Dirac, Wolfgang Pauli, and Erwin Schrdinger. The work of each of these physicists is its own story. The math used by Heisenberg and earlier people is not very hard to understand, but the equations quickly grew very complicated as physicists looked more deeply into the atomic world.

In the early days of quantum mechanics, Albert Einstein suggested that if it were right then quantum mechanics would mean that there would be "spooky action at a distance." It turned out that quantum mechanics was right, and that what Einstein had used as a reason to reject quantum mechanics actually happened. This kind of "spooky connection" between certain quantum events is now called "quantum entanglement".

When an experiment brings two things (photons, electrons, etc.) together, they must then share a common description in quantum mechanics. When they are later separated, they keep the same quantum mechanical description or "state." In the diagram, one characteristic (e.g., "up" spin) is drawn in red, and its mate (e.g., "down" spin) is drawn in blue. The purple band means that when, e.g., two electrons are put together the pair shares both characteristics. So both electrons could show either up spin or down spin. When they are later separated, one remaining on Earth and one going to some planet of the star Alpha Centauri, they still each have both spins. In other words, each one of them can "decide" to show itself as a spin-up electron or a spin-down electron. But if later on someone measures the other one, it must "decide" to show itself as having the opposite spin.

Einstein argued that over such a great distance it was crazy to think that forcing one electron to show its spin would then somehow make the other electron show an opposite characteristic. He said that the two electrons must have been spin-up or spin-down all along, but that quantum mechanics could not predict which characteristic each electron had. Being unable to predict, only being able to look at one of them with the right experiment, meant that quantum mechanics could not account for something important. Therefore, Einstein said, quantum mechanics had a big hole in it. Quantum mechanics was incomplete.

Later, it turned out that experiments showed that it was Einstein who was wrong.[1]

In 1925, Werner Heisenberg described the Uncertainty principle, which says that the more we know about where a particle is, the less we can know about how fast it is going and in which direction. In other words, the more we know about the speed and direction of something small, the less we can know about its position. Physicists usually talk about the momentum in such discussions instead of talking about speed. Momentum is just the speed of something in a certain direction times its mass.

The reason behind Heisenberg's uncertainty principle says that we can never know both the location and the momentum of a particle. Because light is an abundant particle, it is used for measuring other particles. The only way to measure it is to bounce the light wave off of the particle and record the results. If a high energy, or high frequency, light beam is used, we can tell precisely where it is, but cannot tell how fast it was going. This is because the high energy photon transfers energy to the particle and changes the particle's speed. If we use a low energy photon, we can tell how fast it is going, but not where it is. This is because we are using light with a longer wavelength. The longer wavelength means the particle could be anywhere along the stretch of the wave.

The principle also says that there are many pairs of measurements for which we cannot know both of them about any particle (a very small thing), no matter how hard we try. The more we learn about one of such a pair, the less we can know about the other.

Even Albert Einstein had trouble accepting such a bizarre concept, and in a well-known debate said, "God does not play dice".To this, Danish physicist Niels Bohr famously responded, "Einstein, don't tell God what to do".

Electrons surround every atom's nucleus. Chemical bonds link atoms to form molecules. A chemical bond links two atoms when electrons are shared between those atoms. Thus quantum mechanics is the physics of the chemical bond and of chemistry. Quantum mechanics helps us understand how molecules are made, and what their properties are.[2]

Quantum mechanics can also help us understand big things, such as stars and even the whole universe. Quantum mechanics is a very important part of the theory of how the universe began called the Big Bang.

Everything made of matter is attracted to other matter because of a fundamental force called gravity. Einstein's theory that explains gravity is called the theory of general relativity. A problem in modern physics is that some conclusions of quantum mechanics do not seem to agree with the theory of general relativity.

Quantum mechanics is the part of physics that can explain why all electronic technology works as it does. Thus quantum mechanics explains how computers work, because computers are electronic machines. But the designers of the early computer hardware of around 1950 or 1960 did not need to think about quantum mechanics. The designers of radios and televisions at that time did not think about quantum mechanics either. However, the design of the more powerful integrated circuits and computer memory technologies of recent years does require quantum mechanics.

Quantum mechanics has also made possible technologies such as:

Quantum mechanics is a challenging subject for several reasons:

Quantum mechanics describes nature in a way that is different from how we usually think about science. It tells us how likely to happen some things are, rather than telling us that they certainly will happen.

One example is Young's double-slit experiment. If we shoot single photons (single units of light) from a laser at a sheet of photographic film, we will see a single spot of light on the developed film. If we put a sheet of metal in between, and make two very narrow slits in the sheet, when we fire many photons at the metal sheet, and they have to go through the slits, then we will see something remarkable. All the way across the sheet of developed film we will see a series of bright and dark bands. We can use mathematics to tell exactly where the bright bands will be and how bright the light was that made them, that is, we can tell ahead of time how many photons will fall on each band. But if we slow the process down and see where each photon lands on the screen we can never tell ahead of time where the next one will show up. We can know for sure that it is most likely that a photon will hit the center bright band, and that it gets less and less likely that a photon will show up at bands farther and farther from the center. So we know for sure that the bands will be brightest at the center and get dimmer and dimmer farther away. But we never know for sure which photon will go into which band.

One of the strange conclusions of quantum mechanics theory is the "Schrdinger's cat" effect. Certain properties of a particle, such as their position, speed of motion, direction of motion, and "spin", cannot be talked about until something measures them (a photon bouncing off of an electron would count as a measurement of its position, for example). Before the measurement, the particle is in a "superposition of states," in which its properties have many values at the same time. Schrdinger said that quantum mechanics seemed to say that if something (such as the life or death of a cat) was determined by a quantum event, then its state would be determined by the state that resulted from the quantum event, but only at the time that somebody looked at the state of the quantum event. In the time before the state of the quantum event is looked at, perhaps "the living and dead cat (pardonthe expression) [are] mixed or smeared out in equal parts."[3]

People often use the symbol {displaystyle hbar } , which is called "h-bar." = h 2 {displaystyle hbar ={frac {h}{2pi }}} . H-bar is a unit of angular momentum. When this new unit is used to describe the orbits of electrons in atoms, the angular momentum of any electron in orbit is always a whole number.[4]

The particle in a 1-dimensional well is the most simple example showing that the energy of a particle can only have specific values. The energy is said to be "quantized."The well has zero potential energy inside a range and has infinite potential energy everywhere outside that range. For the 1-dimensional case in the x {displaystyle x} direction, the time-independent Schrdinger equation can be written as:[5]

Using differential equations, we can figure out that {displaystyle psi } can be written as

or as

The walls of the box mean that the wavefunction must have a special form. The wavefunction of the particle must be zero anytime the walls are infinitely tall. At each wall:

Consider x = 0

Now consider: = C sin k x {displaystyle psi =Csin kx;}

We can see that n {displaystyle n} must be an integer. This means that the particle can only have special energy values and cannot have the energy values in between. This is an example of energy "quantization."

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Quantum mechanics - Simple English Wikipedia, the free ...

Close your eyes, think of the words eccentric genius, and one of the first images is doubtlessly that of Albert Einstein. He is defined by his characteristic hair and aloofness, too smart and preoccupied with space and time to be consumed by the minutiae of daily grooming.

But the idea of genius is often affected by the same social forces that influence what we perceive as alien, illegal or unsophisticated race, gender, class and other statuses that place individuals and cultures on the wrong side of the line between accepted and outsider.

Stephon Alexander is a theoretical cosmologist and professor of physics at Brown University who has learned how to embrace being different while also succeeding in established spaces. His research challenges conventions of gravity, spacetime and the fabric of the universe. Doubling as a jazz musician, Alexander uses his musical perspective to inform the kind of physics that he does. In his 2017 book, The Jazz of Physics: The Secret Link Between Music and the Structure of the Universe, Alexander compared the constraints of physics with music:

Contrary to the logical structure innate in physical law, in our attempts to reveal new vistas in our understanding, we often must embrace an irrational, illogical process, sometimes fraught with mistakes and improvisational thinking.

In his new book, Fear of a Black Universe: An Outsiders Guide to the Future of Physics, Alexander takes it a step further, bringing readers on a whirlwind ride through the nature of reality, modern physics and the true meaning of being an outsider.

Alexander spoke to The Undefeated about his book, what he means by a Black universe and modern questions in theoretical physics.

This interview has been edited for length and clarity.

Can you walk me through the process and motivation behind Fear of a Black Universe?

I first authored the title as a joke. When an agent asked me what I think the book should be called, one day I said, Fear of a Black Universe.

In hindsight, I think it was one of these subconscious things that had to be the title. And then when we start thinking about quantum mechanics, the dualities and concepts like superposition the idea that a concept could have many meanings. And I know in literature there is some device where you can have an ambiguity in the title of things. And so in my book, theres some of this multiplicity, which I felt was perfect given the ways that I look at the universe.

Of course, the title is a homage and reference to Public Enemys Fear of a Black Planet. That album had a tremendous impact on me. You have to remember that I come from an era where I used to wear African medallions and I was listening nonstop to Public Enemy. The album really influenced me, but more than that, the era. People forget that when hip-hop was new, it really was a culture that everyone was afraid of. It was authored by mostly young, Black and Latinx folks in inner cities, and had a raw energy that intimidated people. And so Fear of a Black Planet embodied a lot of these sensibilities, but came right out and said it you all are afraid of us.

But that isnt where my reference to Blackness ends. The experience of being Black is like a rite of passage, you have to go through things and emerge on the other side. You have to dig deep and strive for that excellence in the face of challenges that you might be facing. And the fact that expectations may not exist for you as a Black man or a Black person, a Black scientist.

And then the other key resonance that that title was about the category of Blackness in a broader sense, like in America, that plays itself out as stigma. And as Black people, we have to deal with stigma, and these other things.

Thats a reality that youre constantly feared, a threat to the status quo. And so, part of what I was getting after with Blackness had to do with authoring ideas that are edgy or potentially threatening.

Thats a reality that youre constantly feared, a threat to the status quo. And so, part of what I was getting after with Blackness had to do with authoring ideas that are edgy or potentially threatening. That as a scientist, you can generate ideas in the name of research, in the name of breaking new ground, that may stigmatize you. That may kick you out of the club, so to speak, because youre not necessarily following the herd.

And I dont mean being actively defiant, but becoming stigmatized in the process of trying to make a difference. And the book was also exploring that with other great breakthroughs in physics, people like Michael Faraday and Albert Einstein and Erwin Schrdinger. Ive learned that they had to navigate that space as well.

So in the book, Blackness is a metaphor for the process of embracing that true outsider status that comes with risk-taking, generating Black ideas.

Hence, Fear of a Black Universe. This is a fear, not only of Black people, but of nontraditional personalities and perspectives.

Youre not satisfied with telling another story about a lonely Black person in a white world. You take pride in being original in the science that you describe. What are some modern ideas in physics that excite you?

Part of my mission is to remind people that unusual backgrounds and experiences can really help to foster new ideas in all of these disciplines. And so, while my background may not show up in the minutiae of my theoretical physics, my identity plays a role in how I think, and so is a character in a lot of things.

With regards to new physics ideas that excite me, I think one of them is probably best summarized by a story.

One of my mentors is Leon Cooper, who won the 1972 Nobel Prize in physics for his work on conductivity. For context: Leon solved this problem that was almost 50 years old, that Albert Einstein and Richard Feynman and a lot of greats worked on.

He has always remained close to me. And Ive always been in touch with him throughout my career. Ill often go check in with him when Im at various crossroads.

Years ago, Im talking to Leon in his office at Brown University. He asks me what Im working on. After hearing my answer, he looks at me, disapprovingly, and says:

You know what you need to do? You need to find a real problem and work on a real problem. People are afraid of working on hard problems because theyre told its impossible. And I think that people are not working hard enough.

I mean, hes going off on me. The man doesnt mince words. Hes a New Yorker like me, one of the reasons that I identify with him.

My interpretation was that I was flattered that he was challenging me to that level. Instead of me taking it negatively, I took that as he respects my intellect so much that hes basically challenging me to pick the hardest problems, the problems that appear to be impossible, and try to solve them.

He finishes his rant, walks up to a blackboard and writes some equations about the big bang on the board, using some clever mathematical tricks. And Im looking, and I think to myself, Wow, thats really interesting.

So a few years went by and it turned out that that thing that he was telling me ended up being the kernel of some ideas surrounding the following paradox: We think that quantum mechanics is something that operates on the microscopic scale. And theres some cases in material systems like metals, superconductors and superfluids where quantum mechanics can operate. But when we start talking about scales of people and buildings and planets, the world is classical, and quantum mechanical effects get washed out.

But this idea that I was inspired to pursue by Leon Cooper claims that at the scale of galaxies, quantum mechanics reappears like a phoenix. And so, theres a chapter in a book called Quantum Galaxies where I talk about this.

One of the hot topics in diversity and inclusion spaces is how we can get more young people of color to have a different image of what a scientist is. You seem to think that being accessible, or cool even, does not clash at all with the image of being smart and scientific. How did you land on this perspective?

Id love to take credit for this, but this really does come from my background.

My family immigrated from Trinidad and Tobago in the late 1970s. I moved to the Bronx at age 8, and was raised there during the 1980s. And so, a lot of what was going on with the development of hip-hop culture was happening right in the neighborhood. And one of the elements in that culture that I dont feel like people have highlighted enough was the importance of having knowledge. That is, on the streets, having knowledge of self and the universe was applauded.

I used to take the bus from my neighborhood to my high school, DeWitt Clinton High School. I used to work on my calculus homework on the ride. And here I am, on the bus, doing my calculus homework. And remember this is the 1980s all sorts of folks would walk through that bus, including some not-too-friendly characters. But a lot of the people on the bus would be all about dropping knowledge. And they would notice me doing my homework.

And from time to time they would engage me, Man, whats up with that mathematics, brother. And I would reply: Im studying derivatives and integration.

And one day a guy said to his friend: This guy is doing supreme mathematics. And from that point on, they basically protected me. Treated me as one of their own, and so I always felt welcome in my community.

This is the same group of guys that encouraged me to go to college. They were like: You need to go to college, get that knowledge and come back.

That sentiment stuck with me. Ive always wanted to bring my knowledge back to the community in whatever way that I could. I never held this idea of a conflict between being authentic and being smart and seeking knowledge. These ideas were never paradoxical growing up in the Bronx.

Now, the media portrayed that differently that our culture was anti-intellectual. But that was not the case where I came from. Being smart has always been a part of being from the streets.

One of the things you emphasize is how to embrace being an outsider. What perspectives can you offer to people who are struggling?

I hope that I said it all in the book! But jokes aside I think Black excellence is a precious idea and must be protected. And in many spaces, Ive found that we can be drawn to safe and comfortable ideas because they feel like they have greater odds of success. One of my career goals is to break this idea its OK being an outsider. Lets embrace it and lean into it. I think thats where our genius lives.

C. Brandon Ogbunu, a New York City native, is a computational biologist at Yale University. His popular writing takes place at the intersection between sports, data science, and culture.

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From Fear of a Black Planet to Fear of a Black Universe - The Undefeated

Newswise Are diamonds even stronger than weve ever imagined? Can other post-diamond phases appear when diamond is subjected to extreme pressures? A team used machine-learned descriptions of interatomic interactions on the 200-petaflop Summit supercomputer at the US Department of Energys (DOEs) Oak Ridge National Laboratory (ORNL) to model more than a billion carbon atoms at quantum accuracy and observe how diamonds behave under some of the most extreme pressures and temperatures imaginable. The results are nothing short of incredible.

The team was led by scientists at the University of South Florida (USF), DOEs Sandia National Laboratories (Sandia), DOEs National Energy Research Scientific ComputingCenter (NERSC), and the NVIDIA Corporation. The researchers found that under extreme conditions, a shock wave strongly compresses the diamond as it passes through and forces it to crack under the pressure.

The study will help scientists better understand how carbon behaves under extreme conditions. This understanding is crucial for inertial confinement fusion, in which hydrogen fuel is kept inside a diamond capsule and nuclear fusion reactions are initiated by compressing the collapsing diamond shell. It is also important for uncovering the internal structure of carbon-rich planetslike Uranusand carbon-rich exoplanets. Exoplanets exist around stars outside of our solar system, and observations suggest they can be rich in diamond and silica.

Observations have shown that some exoplanets consist of carbon-rich constituents, such as methane, which, upon compression, convert to diamond, said Ivan Oleynik, a professor of physics at USF and principal investigator on the project. To understand the structure of these exoplanets, scientists need to understand the behavior of carbon at extreme conditions.

Scientists had believed that under extreme temperatures and pressures, diamond can experience plasticity similar to metals. But as it turns out, diamond experiences a brittle behavior while sustaining its exceptional strength. The team found that these cracks are healed through the formation of amorphous carbon. This carbon is eventually converted into regions of hexagonal diamond, thus explaining the underlying mechanism of diamonds strength.

For this work, the team has been named a finalist for the Association for Computing Machinery Gordon Bell Prize. This prize has been awarded each year since 1987 at the International Conference for High-Performance Computing, Networking, Storage and Analysis (SC). It recognizes outstanding achievements in applying high-performance computing (HPC) to challenges in science, engineering, and large-scale data analytics. The teams results will be presented at SC21, to be held November 1419, 2021, in St. Louis, MO.

Diamonds take the heat

Experiments at Sandias Z Pulsed Power Facility and at Lawrence Livermore National Laboratory (LLNL)facilities capable of creating tens of millions of atmospheres, or 100s of millions of pounds per square inchhave shown that diamond retains extremely high strength even when subjected to enormous compression and heating. It retains this strength up to the state when it should start melting. These experiments involved pressures above several million atmospheres. However, there has been controversy around what actually happens to diamonds under such extreme pressures.

When you load diamond with enormous pressure, it was assumed to turn into a plastic-like state. But we know diamonds are brittle and dont behave in this way, Oleynik said. Our simulations have uncovered an unexpected mechanism of inelastic deformations. Diamond cracks when it is compressed by the enormous shock waves generated at these gigantic compression facilities. These cracks are then reformed during an amorphous-like carbon state inside these cracks. They are then followed by recrystallization into hexagonal stacking faults where the atomic planes are shifted, compared with those in ideal diamond crystals.

Under such extreme conditions, atoms are squeezed together so tightly that only quantum mechanics, which describes how materials behave at the atomic scale, can provide a sufficiently detailed picture of how they interact with one another. But using quantum mechanics to study the dynamics of atoms is computationally expensive.

If you want to simulate something approaching experimental length and timescales, such as micrometers and nanoseconds, you need millions and even billions of atoms and millions of molecular dynamics time steps. But with quantum mechanics, the largest amount of particles you can do is no more than 1,000 atoms. And the largest number of steps is 10,000.

The team made a major breakthrough in describing with quantum accuracy how carbon atoms interact under such enormous pressure and temperature. The team fingerprinted each atom in a diamond using a set of so-calleddescriptors, which were then used to construct an accurate representation of the systems potential energy using powerful machine-learning techniques. This innovative machine-learning approach enabled the team to make predictions of atomic-scale dynamics for a billion atoms to within 3 percent accuracy when compared with extremely precise quantum mechanical calculations.

GPUs illuminate new diamond properties

PhD student Jonathan Willman and postdoctoral associate Kien Nguyen-Cong, both in Oleyniks group at USF, performed the simulations on Summit using a billion-atom sample on the full machine for 24 hours.

Simulating billions of atoms at this nanometer timescale could only be done on Summit. GPU acceleration was the key to achieving these results, Oleynik said. Our team made a major algorithmic breakthrough that allowed our GPU-enabled code to run one hundred times faster than it does on CPU-only machines.

In these billion-atom simulations, the team observed for the first time the shock wave propagation in micrometer-thick diamond at fine resolution, down to the atomic scale. This allowed the team to observe details of diamond cracking and reforming, as well as complex interference patterns created by multiple local sound waves initiated at the crack tips.

We couldnt see this before because we had never done such grand-scale simulations, Oleynik said. The cross section of the diamond sample the team used in simulations is 100 by 100 nanometers and 1 micronor 1,000 nanometersin length.

Running the simulations at such a grand scale is important because now we can achieve high fidelity, and we can say for certain that our results are close to reality, Oleynik said.

Reaching an unknown phase of carbon

Thanks to Summit, the team also has a better understanding of why diamonds havent been transformed to the so-called BC8 high-pressure, post-diamond phase in billion-dollar experiments at the National Ignition Facility (NIF) at LLNL.

These experiments pursued conventional thinking of concerted transformation of atoms from a diamond lattice to that of the BC8 phase. This phase transition requires overcoming an enormous energy, Oleynik said. Our hypothesis, which was brilliantly confirmed in our billion-atom simulations, is that the liquid-like, amorphous carbon can facilitate the nucleation of the BC8 phase. This provides a viable pathway for synthesis of this post-diamond phase. Within the NIF Discovery Science program, we are working with our experimental collaborators to confirm our predictions.

The team plans to extend their simulations to even bigger, trillion-atom systems using emerging exascale HPC systems. These include the nations first exascale supercomputer, Frontier at the Oak Ridge Leadership Computing Facility(OLCF), a DOE Office of Science user facility located at ORNL.

Such tour de force simulations will provide even deeper insight into mystery of diamond rain upon compression of methane inside of ice giants Uranus and Neptune, Oleynik said. The beauty of these simulations is that we can see how nature responds to these extreme pressures and temperatures at the atomic level. We can also see how individual atomic motions combine together in a collective macroscopic behavior, which can then be observed in state-of-the art experiments.

The team members include Jonathan Willman, Kien Nguyen-Cong, and Ivan Oleynik from USF; Stan Moore, Mitchell Wood, and Aidan Thompson from Sandia; Rahulkumar Gayatri from NERSC; and Evan Weinberg from the NVIDIA Corporation.

Sandia is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for DOEs National Nuclear Security Administration (NNSA).

The research is supported by NNSA; the Exascale Computing Project, a collaborative effort of the DOEs Office of Science and NNSA; and DOEs Advanced Scientific Computing Research Leadership Computing Challenge and Innovative and Novel Computational Impact on Theory and Experiment awards. This research used resources of NERSC and the OLCF.

Related Publication: Nguyen-Cong, Kien, Jonathan T. Willman, Stan G. Moore, Anatoly B. Belonoshko, Rahulkumar Gayatri, Evan Weinberg, Mitchell A. Wood, Aidan P. Thompson, and Ivan I. Oleynik. Billion Atom Molecular Dynamics Simulations of Carbon at Extreme Conditions and Experimental Time and Length Scales. Paper to be presented at SC21: The International Conference for High Performance Computing, Networking, Storage and Analysis, St. Louis, MO, November 2021.

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Team Earns Gordon Bell Prize Finalist Nomination for Simulating Carbon at Extreme Pressures and Temperatures - Newswise

Did you know Bo once had his own video games?

Bo Jackson, a former NFL running back for the Los Angeles Raiders and Major League outfielder, is the only player to be named a Pro Bowler in football and All-Star in baseball. So, in 1990, American toy manufacturer Tiger Electronics released a handheld game allowing users to play with Jackson on both the football and baseball fields. The next year, Nintendo dropped Bo Jacksons Hit and Run for Game Boy and Bo Jackson Baseball for the Nintendo Entertainment System.

Yet his trio of games likely wouldnt have been possible without the virtual stardom he garnered in 1989s Tecmo Bowl, the first console game to earn a license from the NFL to feature players by name, image and likeness. To this day, Jackson in Tecmo Bowl and 1991s Tecmo Super Bowl is considered one of the greatest video game avatars, along with Michael Vick from Madden NFL 2004.

Madden was first released on PC in 1988 during Jacksons second season in the NFL. But due to licensing issues and a hip injury during the 1990 NFL season that forced his early retirement from football, Jackson never appeared in Madden during his playing days. It wasnt until 2014 that Jackson made his Madden debut as a special-edition player in the Ultimate Team game mode.

On Wednesday, EA Sports announced that not only will Jackson return to the game for the first time since Madden NFL 15, but hell also receive the honor of becoming a Madden cover athlete. Nearly 35 years after his NFL career began in 1987, Jackson will grace a special digital cover of Madden NFL 22. And beginning Friday, gamers will once again be able to play with him virtually. EA Sports also teamed up with Nike to revisit the sportswear companys famous Bo Knows ad campaign by incorporating a digitally rendered version of his signature shoe, the Nike Air Bo Turf, into the game.

EA Sports

Jackson is the seventh running back to be named a Madden cover athlete, following Eddie George (Madden 2001), Marshall Faulk (Madden 2003), Shaun Alexander (Madden 2007), Peyton Hillis (Madden 12), Adrian Peterson and Barry Sanders (both Madden 25).

Before the cover unveiling, The Undefeateds Aaron Dodson caught up with Jackson to talk about his Tecmo Bowl days, how Bo Knows came to life, his Madden return and more.

This conversation has been edited for clarity and length.

What does it mean to you to finally be a cover athlete for the game, 35 years after your career began?

This has been in the works off and on for years. The time had to be right for my brand. Working with the Madden people to iron things out, dot all the is, cross all the ts once we got that done, the rest was just going for it. I figured that, somewhere in my past, I did something right in order to still be looked at as one of the iconic athletes from over 30 years ago. Madden still thinks enough of me to do something like this.

Your video game legacy dates back to 1989 when you became the star of Tecmo Bowl. What was it like seeing yourself virtually back then?

I still see myself in Tecmo Bowl. Ive still got the video game. Ive still got the machine to play it on. But its in a box somewhere in storage. Its iconic. It really makes me feel good that I have grown men in their 40s saying, Hey, my cousin and I got into the biggest fight of our lives because we both wanted to be you in Tecmo Bowl when we were young. So our parents took the game and my dad locked it up in his tool cabinet. We couldnt play with it for a month because the fight was so intense. I hear that a lot. When Im at sports memorabilia shows, people come up with that video game. They say, I still got the machine to play it on. My kids play it. My grandkids play it and everybody still argues about who is gonna be Bo Jackson. Tecmo Bowl that was a lot of technology back then. You look at it now and its like, Wow, thats an antique.

Is it true that youve never played Tecmo Bowl?

I have never played Tecmo Bowl. Thats the Gods honest truth. I have watched people play it a lot. But I knew what I could do. I knew what the Tecmo Bowl man could do. It gives me pleasure to listen to people compliment me from that game.

Part of your video game return to Madden includes celebrating Nikes iconic Bo Knows campaign. Take us back to the beginning. How did the brand present the idea of Bo Knows to you?

We came across Bo Knows accidentally. Directors, writers, sketchers we were sitting around going over some storyboards for our next shoot. We wanted to cut it down because it was a little too long. Everybody was giving their opinion on this and that. I just said, Why dont we do this? Why dont we move this over here, put this here, combine it and cut out about five or six seconds? They looked at me and said, Wow. Thatll probably work. Then somebody across the table looked at me and said, Bo Knows! And it stuck. Nobody sat down and racked their brains or stayed up all night thinking of that catchphrase. It just happened sitting around the war table going over shoots.

Before you got a signature shoe, the Nike Air Bo Turf, in 1990, you headlined the Nike Air Trainer 3, which became known as your shoe. What memories do you have surrounding the Air Trainer 3?

Well, Ill put it to you like this. In 1969, when I was in the first grade growing up in rural Alabama, during the winter, it was in the mid-30s outside. And I had to go to school barefoot. No shoes. Im not saying this for sympathy or as a sob story. But I can remember my brother standing a block away from the house. Im at the front door. My sister was standing a block away from my brother and my other sister was at the bus stop. When my sister at the bus stop saw the bus top the hill a couple of blocks away, she would yell to my other sister, who would yell to my brother, and my brother would yell to me. Then Id take off out the door barefoot. And by the time my brother got to my first sister, I wouldve caught him already. By the time we got to the bus stop, Im 15, 20 yards in front of my brother and sister. From going to school barefoot during the winter of 69 to growing up and having a sneaker inspired by me I was blessed.

After 30 some odd years, people still brag about that shoe and collect that shoe. A couple of weeks ago, a good friend of mine, Anthony Anderson, the comedian, he texts me, Hey, Bo! Im doing a show about all my sneakers. I cant find your Air Trainers. I need a pair of your shoes! It just so happened I had a pair sitting in my office. I said, Hey, well, I got a pair here. I can just send them to you. Its moments like that where I sit back and go, Wow.

EA Sports

This NFL season, New York Giants running back and Nike athlete Saquon Barkley received his own version of the Air Trainer 3. How did it feel to see him pay homage to you through the sneaker?

I blessed him with those shoes. It was like me saying, Grasshopper, its your time now to carry this torch. And you have to carry it well. I know that he will do a good job of that. Saquon is a good kid. He reminds me a lot of myself. Runs with power and has his head on straight. Thats the thing that impresses me most. Its not his stats. I love the way he carries himself.

There will always be one Bo Jackson. But when you reflect upon the NFL running backs whove come after you, which ones remind you most of yourself?

I can only think of two Saquon and Derrick Henry on the brute strength, power and knowing how to navigate around the field and defense. They dont necessarily have the speed I had. But they have made it work for them. They are very successful at what they do. And thats why theyre looked at as top of the top running backs in the game right now.

When you look back at your career, whats one play you made that you feel couldve come out of a video game?

The one that nobody talks about except Denver Broncos fans is when we went to Denver and I went through their defense on one play like a hot knife through butter. Not bragging, but its just the fact being the size that I was then and how low I learned in college to run behind my pads. Which means you would never catch me upright running unless I had someone 5 or 6 yards behind me trying to chase me. But when I was up in traffic, in the thick of things, it only took me one time to realize that not running behind your pads is bad for you. I cant think of the gentlemans name, but it was a linebacker from the Cardinals when they were in Phoenix. He blew me up. He hit me on the 6- or 7-yard line and dropped me on the 2. He helped me get up and said, Hey, Bo, look, you need to make me earn my check. You need to run harder. Im looking at him like, You done lost your damn mind. Im not going up in that hole no more. The next play, I bounced it outside and used my speed.

EA Sports

Editors note: In the fourth quarter of a game between the Raiders and Broncos on Dec. 2, 1990, Jackson scored a 62-yard rushing touchdown, breaking five tackles en route to the end zone. He finished the afternoon with 13 carries for 117 yards and two scores.

That [Denver] game, once I got through the linemen, I ran over a linebacker, jumped over somebody else. And if Im not mistaken, I hit their All-Pro linebacker, [Karl] Mecklenburg, and outran the defensive back to the goal line. Thats one play that stands out to me because I had to do everything from make somebody miss, jump, get low and go for 60 yards for a touchdown.

What went through your mind when you saw yourself on the Madden cover?

I just sat back and said, Man, you still got it. I did something right. And thats what I preach to guys like Derrick Henry and Saquon Barkley: Do it right. If you do it right the first time, you will be remembered forever.

The Madden curse cant affect you at this point, right?

The Madden curse? [Laughs.] It cant affect me.

You didnt play with yourself in Tecmo Bowl. Are you gonna play with yourself in Madden?

I dont know. But the thing that Im doing right now is spending a lot of time with my new grandson. So Ill probably get the game and save it for him. But I am looking forward to it coming out. Believe you me, I will have my case of Madden games to give out for Christmas presents.

Aaron Dodson is a sports and culture writer at The Undefeated. He primarily writes on sneakers/apparel and hosts the platforms Sneaker Box video series. During Michael Jordans two seasons playing for the Washington Wizards in the early 2000s, the Flint Air Jordan 9s sparked his passion for kicks.

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Bo Jackson makes video game history again with his first Madden cover - The Undefeated

With skin brushed then tangled, with the apple touched at the supermarket then tangled,with the tear wiped then woven away,tangled with even things very distant like Mars dust,that unravel themselves when /touched by our gaze

Excerpt from Miriam Manglanis poem Makindes Quantum World, about Makinde Ogunnaikes quantum physics research

Senior MIT physics doctoral student Olumakinde Makinde Ogunnaike briefly traded his research for verse as a participant in The Poetry of Science, an initiative funded by the Cambridge Arts Council that pairs poets of color with scientists of color from MIT and other area schools to artistically express their scientific work through art and poetry. Ogunnaike and other area scientists were invited by Joshua Sariana PhD 11, who studied neuroscience with the Department of Brain and Cognitive Sciences, and who tapped into his photography and writing talents to co-produce the art exhibit.

A Nigerian-American native of Delaware, Ogunnaike studied physics and math at Harvard University, and received a masters in philosophy of physics at Oxford University before coming to MIT to study condensed-matter physics theory. He is a graduate student working with Professor Leonid Levitovs group, studying emergent bound states in mixed Bose-Fermi systems and entanglement dynamics.

I deal with systems where quantum theorys strangeness manifests in emergent properties. Instead of new fundamental particles, I look for materials with unintuitive properties that arise from a chorus of delicate quantum connections. One line of work involves studying collections of cold atoms that bind together to form composite atoms themselves. Another focuses on the effects of measurement and symmetry on the spread of quantum entanglement correlations between quantum particles.

Working with poet Miriam Manglani to explain his research, Ogunnaike decided to focus on the areas where his research and his faith intersected. They jointly edited the poem, and a photographer took his portrait. The project was a natural fit for him, as he also runs a poetry and tea event at Harvard.

We get a lot of STEM students bringing in their own perspectives and interests, so this project felt perfect, he says. My interest in devotional art, in particular, feels like it comes from the same place as my interest in physics: interest in understanding fundamental structures. I particularly love African art, which resonates with me personally, and religious or devotional art, like poetry, music, and paintings, since these usually have extra meaning as a way of knowing or interacting with the divine.

He is a co-founder of the Harvard-MIT Chapter of the National Society of Black Physicists (NSBP), and a founding member of the MIT Physics Working Group to promote changes in diversity and inclusion to the department. His career goals are to teach physics at a liberal arts college where I can teach philosophy of physics and support underrepresented students.

Other MIT participants in the project include students, technicians, postdocs, and alumni. They include biology doctoral candidates Christian Loyo and Sheena Vasquez, Broad Institute of MIT and Harvard postdoc Michael Wells, electrical engineering and computer science majors Kathleen Esfahany and Suparnamaaya Prasad; Koch Institute for Integrative Cancer Research technician Nandita Menon, mechanical engineering and theater alumna Luisa Apolaya Torres 21; and Media Lab PhD candidates Huili Chen and Shannon Johnson.

This project is a collaboration withThe Peoples HeART, a joint community health-care initiative led by physics alumnus Daniel Chonde '07, PhD '15, who is also featured in the exhibit. After Chonde studied particle physics at MIT, he received his PhD in biophysics from Harvard, with a joint degree from MIT in medical engineering and medical physics. After Harvard Medical school he became a resident in the Department of Radiology at Massachusetts General Hospital.

The Poetry of Science will be featured in the lobby of Mass General through the end of November, and at an exhibition at the Rotch Library at MIT during Independent Activities Period in January 2022. The poems were presented at the Boston Lit Crawl on June 10 at the Starlight Space in Central Square, and will be published in Spry Literary Journal.

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The poetry of physics - MIT News

For all of history, theres been an underlying but unspoken assumption about the laws that govern the Universe: If you know enough information about a system, you can predict precisely how that system will behave in the future. The assumption is, in other words, deterministic. The classical equations of motion Newtons laws are completely deterministic. The laws of gravity, both Newtons and Einsteins, are deterministic. Even Maxwells equations, governing electricity and magnetism, are 100% deterministic as well.

But that picture of the Universe got turned on its head with a series of discoveries that began in the late 1800s. Starting with radioactivity and radioactive decay, humanity slowly uncovered the quantum nature of reality, casting doubt on the idea that we live in a deterministic Universe. Predictively, many aspects of reality could only be discussed in a statistical fashion: where a set of probable outcomes could be presented, but which one would occur, and when, could not be precisely established. The hopes of avoiding the necessity of quantum spookiness was championed by many, including Einstein, with the most compelling alternative to determinism put forth by Louis de Broglie and David Bohm. Decades later, Bohmian mechanics was finally put to an experimental test, where it failed spectacularly. Heres how the best alternative to the spooky nature of reality simply didnt hold up.

There are all sorts of experiments we can perform that illustrate the indeterminate nature of our quantum reality.

The list of experiments that display this sort of quantum weirdness or spookiness is long, and these examples are far from exhaustive. This inherently quantum behavior shows up in all sorts of physical systems, both for individual particles and for complex systems of particles as well, under a variety of conditions. Although physicists have been able to write down the rules and equations that govern these quantum systems, including the Pauli Exclusion Principle, the Heisenberg Uncertainty Principle, the Schrodinger equation and many more, the fact is that only a set of conditions and probable outcomes can be predicted in the absence of a measurement.

Somehow, in quantum systems, the act of making a measurement appeared to be a very important factor, flying in the face of the idea that we inhabited a sort of independent reality that was observer-independent. Properties of a physical system that had previously been treated as intrinsic and immutable like position, momentum, angular momentum, or even the energy of a particle were suddenly knowable only up to a certain precision. Moreover, the act of measuring those properties, which required an interaction with another quantum of some type, fundamentally changes, or perhaps even determines, those values, while simultaneously increasing the indeterminism and/or uncertainties of other measurable parameters.

The central idea behind what we now call the Copenhagen Interpretation of quantum mechanics, which is the standard way that physics students are taught to conceive of the quantum Universe, is that nothing is certain until that critical moment where an observation occurs. Everything that cannot be exactly calculated from whats already known is describable by some sort of wavefunction a wave that encodes a continuum of more likely and less likely possible outcomes until the critical moment when a measurement is made. At that precise instant, the wavefunction description gets replaced by a single, now-determined reality: what some describe as a collapse of the wavefunction.

It was this level of weirdness, or spookiness, that was so objectionable to many. Einstein was perhaps the most famous. He was aghast at the idea that somehow reality was random in nature, and that effects could occur like one member of a pair of identical atoms decaying while the other did not without an identifiable cause. In many ways, this position was summed up in a famous remark attributed to Einstein, God does not play dice with the Universe. While Einstein himself never came up with an alternative, one of his (and Bohrs) contemporaries had an idea for how reality could work instead: Louis de Broglie.

In the early days of quantum mechanics, de Broglie gained fame for showing that it wasnt simply light that possessed a dual nature of being simultaneously wave-like and particle-like, but that matter itself possesses a wave-like nature when subjected to the proper quantum conditions. His formula for calculating the wavelength of matter waves is still widely used today, and to de Broglie, its because we ought to be taking the dual nature of quanta literally.

In de Broglies version of quantum physics, there were always concrete particles, with definite (but not always well-measured) positions to them, that are guided through space by these quantum mechanical wavefunctions, which he called pilot waves. Although de Broglies version of quantum physics couldnt describe systems with more than one particle, and suffered from the challenge of not being able to measure or identify precisely what was physical about the pilot wave, it represented an interesting alternative to the Copenhagen interpretation.

Instead of being governed by the weird rules of quantum spookiness, there was an underlying, hidden reality that was completely deterministic. Many of de Broglies ideas were expanded upon by other researchers, who all sought to discover a less spooky alternative to the quantum reality that generations of students, with no superior alternative, had been compelled to accept.

Perhaps the most famous extension came courtesy of the physicist David Bohm, who in the 1950s developed his own interpretation of quantum physics: the de Broglie-Bohm (or pilot wave) theory. The underlying wave equation, in this idea, is the same as the conventional Schrodinger equation, as in the Copenhagen interpretation. However, theres also a guiding equation that acts on the wavefunction, and properties like the position of a particle can be extracted from the relationship of that guiding equation. Its an explicitly causal, deterministic interpretation, with a fundamental non-locality to it.

But this interpretation posed its own difficulties. For one, you cant recover classical dynamics using this pilot wave theory; Newtons F = ma doesnt describe the dynamics of a particle at all. In fact, the particle itself doesnt affect the wavefunction in any way; rather, the wavefunction describes the velocity field of each particle or system of particles, and you have to apply the appropriate guiding equation to find out just where the particle is and how its motion is affected by whatever is exerting a force on it.

In many ways, pilot wave theory was more of an interesting counterexample to the assertion that no hidden variable theory could reproduce the success of quantum indeterminism. It could, as Bohms pilot wave theory illustrated, but at the cost of a fundamental non-locality and the difficult notion of having to extract physical properties from a guiding equation, whose results are not necessarily straightforward to work with.

Consider the following example: a particle, like a ball, floating on top of a flowing river. In Newtonian mechanics, what happens to the ball is simple: The ball has a mass, which means it has an inertia, and that means it follows Newtons first and second laws. This object in motion will remain in motion unless acted on by an outside force. If it is acted upon by an outside force, it accelerates via that famous equation, F = ma. As the ball travels downstream, the rivers twists and turns will cause the water to flow downstream, but will quickly drive the ball to one bank of the river or the other. Inertia is the guiding principle behind the floating balls motion.

But in Bohmian mechanics, the flow of the river determines the evolution of the wavefunction, which should preferentially stay in the center of the river. This shows the conceptual difficulty with pilot wave theory: If you want your particle to ride on the wavefunction like a surfer as de Broglie originally envisioned you have to go through a variety of twisted contortions to get back the basic predictions that were all familiar with from classical mechanics.

As the perfectly valid Copenhagen interpretation has long demonstrated, however, just because something is counterintuitive or even illogical doesnt mean its incorrect. Physical behavior is often more bizarre than wed ever expect, and that is why we must always confront our predictions with the harsh reality of experiments.

In 2006, physicists Yves Couder and Emmanuel Fort began to bounce an oil droplet atop a vibrating fluid bath made out of that same oil, recreating the analogue of the quantum double-slit experiment. As the wave ripples down the tank and approaches the two slits, the droplet bounces atop the waves and is guided through one slit or the other by the waves. When many droplets were passed through the slits and a statistical pattern emerged, it was found to exactly reproduce the standard predictions of quantum mechanics.

In 2013, an expanded team led by John Bush at MIT leveraged the same technique to test a different quantum system: confining electrons into a circular corral-like area by a ring of ions. To the surprise of many, with an appropriately set up boundary, the underlying wave patterns that are produced are complex, but the trajectory of the bouncing droplet(s) atop them do, in fact, follow a pattern determined by the wavelength of the waves, in agreement with the quantum predictions that underlie them.

What appeared to be random, in these experiments, wasnt truly random at all, but rather provided a thrilling confirmation of the ideas of pilot wave theory.

And then it all fell apart.

Normally, the double slit experiment only gives you the vaunted interference pattern if you dont measure which of the two slits the particle passes through. At quantum scales, setting up a detector at the slits themselves tells you which slit each particle goes through, but destroys the interference pattern. You simply get two piles of particles on the other side, with each pile corresponding to one of the two slits.

In Couder and Forts original 2006 experiment, they had set 75 separate bouncing droplets through the slits where they could watch which slit each droplet passed through while also recorded the pattern of where they landed on the screen finding the needed interference pattern. If this held up, it would seem to confirm that, perhaps, there really could be these hidden variables underlying what appeared to be an indeterminate quantum reality.

And then the reproduction attempts came. Lo and behold, as soon as the path through one of the two slits was singled out by each droplet, the paths that the particle takes depart from what quantum mechanics predicts. There was no interference pattern, and it was found that the original work contained a few mistakes that were corrected in the reproduction attempt. As the authors of the 2015 study refuting Couder and Forts work conclude:

We show that the ensuing particle-wave dynamics can capture some characteristics of quantum mechanics such as orbital quantization. However, the particle-wave dynamics can not reproduce quantum mechanics in general, and we show that the single-particle statistics for our model in a double-slit experiment with an additional splitter plate differs qualitatively from that of quantum mechanics.

Of course, arguing over whether reality is truly acausal, truly indeterminate, or lacking any hidden variables is tantamount to playing a never-ending game of whack-a-mole. Any specific claim that can be tested can always be ruled out, but it can be replaced with a more complex, hitherto untestable claim that still purports to have whatever aspects (or combination of aspects) one desires. Still, when assembling our picture of reality, its important to make sure that we dont ideologically choose one that conflicts with the experiments we can perform.

We may not have the ultimate right answer to the question of how the Universe works, but we have knocked down a tremendous number of pretenders from the throne. If your predictions disagree with experiments, your theory is wrong, no matter how popular or pretty it happens to be. We have not yet ruled out all possible incarnations of Bohmian mechanics, or pilot wave theories, or quantum mechanics interpretations that have hidden variables. It may not ever be possible to do so. However, every attempt to construct a theory that agrees with experiment requires some level of quantum spookiness that simply cannot be done away with. The least spooky alternative has now been falsified, as a single, concrete reality cannot describe all that we observe and measure.

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How the best alternative to "quantum spookiness" failed - Big Think

By Andreas Rinke

BERLIN (Reuters) European countries must work together on next-generation chip manufacturing, Angela Merkel said, drawing on her 16 years of experience in the highest office to warn that no European country could stay at the forefront of high-tech on its own.

The outgoing German chancellor told Reuters in an interview that the costs of moving to the next level in areas from chip development to cloud and quantum computing and battery production meant that the private sector would need state support.

Merkel herself conducted fundamental research in quantum chemistry in East Germany before entering politics after German reunification in 1990. She pointed to Korea, Taiwan and U.S. President Joe Bidens stimulus package as examples of what was possible.

The state will have to play a significant role. South Korea and Taiwan go to show that competitive chip production in the 3-or 2-nanometer range, for example, is essentially impossible without state subsidies, she said.

The global economys current struggle to restore supply chains snapped by resource shortages and the coronavirus pandemic further highlights the need to ensure that Europe has its own production facilities in key areas, she said.

But she also lamented the failure of German companies to capitalise on an outstanding research base.

In particular, she said she was shocked at German companies lack of interest in quantum computing, even though Germany was a world leader in research in a field that could make computers faster and more powerful than ever before.

NO ALEXA FOR ANGELA

She said her government had made steps towards improving Germanys innovation and start-up cultures, pointing to a German-led project to create a secure and efficient cloud data infrastructure for Europe, named Gaia-X.

But in the long term it cannot be the state that drives new developments, the European Unions longest-serving leader said.

Germanys sprawling, decentralised government structure could also be a hindrance to innovation.

Merkel said the presence of an ethics council and data protection officer in each of the 16 federal states put a heavy burden on firms in life sciences, for instance, where Germany had fallen behind.

It was, however, at the leading edge of research in areas such as quantum physics, climate research, physics, chemistry and robotics, she said.

Not that the same could be said for Merkels own use of home technology.

Im happy enough when I can set up a delayed start on my washing machine, but beyond that, to be honest, I have neither the time nor the inclination to have my whole home remote-controlled, she said.

Maybe Ill develop an interest when I have more time in the near future.

(Reporting by Andreas Rinke in Berlin; Writing by Thomas Escritt; Editing by Kevin Liffey)

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Exclusive-Europe must work together to stay at forefront of high-tech Merkel - KFGO News

Special relativity could open the door to ultra-secure ATM machines.

It's Monday morning and you're headed to grab an espresso from a corner cafe. Upon entering, you run into the dreaded "cash only" sign. "No problem," you think, wandering to the nearest ATM. You arrive at the machine, slip out your debit card, insert its worn chip and cup your hands into mini-shields while punching in your secret PIN.

During the process, however, sly thieves might have seen past your humble security measures. They may have even preemptively hacked the cash machine to collect your code. To withdraw money for coffee, you've actually risked theft.

Unlock the biggest mysteries of our planet and beyond with the CNET Science newsletter. Delivered Mondays.

Could there be a safer way to do this? A team of researchers hailing from Canada and Switzerland are determined to find out. They published a blueprint in the journal Natureearlier this month that detailed an ultra-secure cash machine that would completely reinvent the system.

"The assumption of trusting the device when you are doing anything related to identification is kind of a problem, at least at the fundamental level," said Sbastien Designolle, a physicist at the University of Geneva and co-author of the study.

"Drop all assumptions" is the motto he and fellow researchers abided by while coming up with a more secure mechanism to retrieve cash.

Anchoring their far-fetched idea with physicist Albert Einstein's theory of special relativity, they propose replacing the PIN system with what's called a zero-knowledge proof.

Here's how it works.

Remember brain teasers? Zero-knowledge proofs are like a grownup version of such mind games. In cryptography, which is the study of secure communication, they're a method by which party A proves to party B that they know something. The catch is, party A, the prover, can't reveal the information they know to party B, the verifier.

But there's a way for party A to get around the caveat.

Suppose you have a friend named Jones who can only see in black and white, but you can see in color. Your objective is to prove to Jones you can, in fact, see color. If you were to use a zero-knowledge proof, it might go something like this:

Jones holds a red card and a blue card before you. Then, behind his back, he either swaps them or doesn't swap them. Laying them out in front of you again, he asks, "Did I swap them?"

The game could be repeated a hundred times, and you'll always have the correct answer because you can see the colors. After many iterations, Jones would eventually say, "Alright, I believe you. You can see color." At that point, you've shown him your color-identifying ability without revealing the colors you see.

"In our study," explained Designolle, "the proof is the three-colorability of a graph."

Albert Einstein's theory of special relativity could get a new practical application.

There's some lore behind the idea. Three-colorability is a notoriously difficult mathematical problemthat theorists have studied for years. It posits the question: How can you color an enormous map of shapes with three shades such that the same colors never touch?

This wouldn't be like world maps we're used to. It'd be so huge that humans need technology to comprehend it, but even with such help, Designolle said it would take years to find a three-colorability solution.

Taking the concept to ATMs, he suggests giving everyone a device holding a uniquely colorized map with a preprogrammed three-colorability solution. To withdraw cash, you'd plug the device into an external outlet on the ATM, the verifier in this case.

The machine would query your device, or prover, with hundreds of thousands of questions regarding sections of your map's colors. Despite the complexity of three-colorability, your device would immediately answer because it's been preprogrammed.

Further, because every round of queries is randomized, even if the verifier asks about different edges, the ATM would never receive enough information to know the full map, Designolle explained, "which is the crucial point."

Eventually, like in the situation with Jones, the ATM will verify your identity and roll out your cash because of your device's consistently correct answers -- like the way Jones said, "Alright, I believe you. You can see color." Ta-da.

The invention seems solid -- to me, at least. But Designolle and his team aimed to drop all assumptions. They still didn't completely trust the security of the three-color map system.

Hypothetically, they argue, someone could record your device's sparse answers about its map and attempt to reverse calculate the full picture, enabling them to fake your identity.

"Those functions that you can perform in one direction are very difficult, but not impossible, to compute in the other direction," Designolle said.

For example, if you multiply two prime numbers and get a very big number, it's difficult to go back to the elementary numbers. But that doesn't bar it from being done. The same applies to three-colorability.

So, how can we take these machines to a level of unconditional security? Designolle thought, well, what about invoking two devices?

"The idea behind this is precisely the same as a policeman investigating and asking two separate suspects [questions] in different rooms, so that they can't communicate," Designolle said. "If they are telling the same version of the story, then it's a good hint they actually are telling the truth."

Two ATMs, two devices -- ultimate safety?

Back to the cash machine.

With two devices, you'd divide yourself into two provers, like the two suspects. Then, two verifiers, ATMs, will simultaneously ask its respective prover the usual three-colorability questions.

Yes, you would have to plug two separate devices into two separate ATMs. At present, the researchers say the system works with the ATMs standing 60 meters (about 196 feet) apart. But they say they can get it down to a meter, or about 3 feet. It sounds overly complicated, but remember, the purpose of the experiment is to illustrate what an unconditionally secure cash machine mechanism might look like. It's theoretical -- for now, at least.

If each prover appears to hold the same, incalculable knowledge, it'd be safe to say that your identity is verified.

And like the criminal suspects, the devices wouldn't be able to communicate with each other. Any potential hacker would need to reverse calculate not one, but two, complex maps at the exact same time, an exceptionally challenging -- if not impossible -- task.

Here's the moment you've been waiting for -- where Einstein comes in. The reason these devices wouldn't be able to communicate is they'd be bound by Einstein's theory of special relativity.

Einstein's theory of special relativity beautifully marries the realms of space and time. But more importantly for Designolle's team, it also leads to constraints on how fast information travels.

"With special relativity," Designolle said, "it seems quite reasonable to believe in this not computational but physical assumption ... that information cannot go faster than the speed of light."

As long as the two ATMs ask their respective plugged-in, map-filled devices questions quickly enough for lags to always remain shorter than the time needed to transfer information -- restricted by the speed of light -- we'd guard against the possibility of the devices talking to each other.

In a sense, the provers couldn't check their "alibis" to fake an identity.

There's just one, final issue. These relativistic constraints aren't so airtight when it comes to nonconventional physics. Enter quantum computing.

Light works differently in the quantum world. Quantum mechanics allows for a fascinating principle called quantum entanglement. Put simply, when two quantum particles -- namely, light particles -- are entangled, they can instantaneously communicate.

It's not even a matter of how fast the information travels. It's immediate. If particle A holds knowledge of something, you can be absolutely sure particle B already knows it too.

IBM's quantum computer

"Suppose that I do not have the coloring of a graph, but I want to pretend that I do," Designolle said, referring to a potential hacker. "I could come up with a procedure using quantum entanglement between the two chips to answer the questions correctly. In a way, I can cheat."

While Designolle's team believes their mechanism should be able to guarantee safety from quantum hackers, they're not sure. However, they're currently pondering whether the protocol could itself use quantum provers instead of standard devices.

And if you've gotten this far, you might be wondering exactly how theoretical these ultra-secure ATMs are. Is it even possible to bring them into reality?

Right now, Designolle said, the main issue is cost. In order to create the devices needed for the mechanism, the chips can't be the same type we find on our debit cards today. They will have to be extremely powerful, which means they'll likely be very expensive. One idea he has is to invoke the system for large companies that trade secure information and can afford the pricey chips.

That would actually make the relativistic constraints looser because there would be a greater distance between each party's device and the verifying "cash machine," so light would take longer to travel. This means there'd be more room for lags before hackers can penetrate the system.

But aside from the realistic applications, Designolle said, "On a personal note, it was really interesting just to see that sometimes something very simple is actually hard to come up with. ... At some point, yes, this occurred, but it was not very clear from the beginning that it would be so simple in the end."

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Einstein's theory of special relativity could help create unhackable ATMs - CNET

Blackbody radiation refers to the spectrum of light emitted by any heated object; common examples include the heating element of a toaster and the filament of a light bulb. The spectral intensity of blackbody radiation peaks at a frequency that increases with the temperature of the emitting body: room temperature objects (about 300 K) emit radiation with a peak intensity in the far infrared; radiation from toaster filaments and light bulb filaments (about 700 K and 2,000 K, respectively) also peak in the infrared, though their spectra extend progressively into the visible; while the 6,000 K surface of the Sun emits blackbody radiation that peaks in the centre of the visible range. In the late 1890s, calculations of the spectrum of blackbody radiation based on classical electromagnetic theory and thermodynamics could not duplicate the results of careful measurements. In fact, the calculations predicted the absurd result that, at any temperature, the spectral intensity increases without limit as a function of frequency.

In 1900 the German physicist Max Planck succeeded in calculating a blackbody spectrum that matched experimental results by proposing that the elementary oscillators at the surface of any object (the detailed structure of the oscillators was not relevant) could emit and absorb electromagnetic radiation only in discrete packets, with the energy of a packet being directly proportional to the frequency of the radiation, E = hf. The constant of proportionality, h, which Planck determined by comparing his theoretical results with the existing experimental data, is now called Plancks constant and has the approximate value 6.626 1034 joulesecond.

Planck did not offer a physical basis for his proposal; it was largely a mathematical construct needed to match the calculated blackbody spectrum to the observed spectrum. In 1905 Albert Einstein gave a ground-breaking physical interpretation to Plancks mathematics when he proposed that electromagnetic radiation itself is granular, consisting of quanta, each with an energy hf. He based his conclusion on thermodynamic arguments applied to a radiation field that obeys Plancks radiation law. The term photon, which is now applied to the energy quantum of light, was later coined by the American chemist Gilbert N. Lewis.

Einstein supported his photon hypothesis with an analysis of the photoelectric effect, a process, discovered by Hertz in 1887, in which electrons are ejected from a metallic surface illuminated by light. Detailed measurements showed that the onset of the effect is determined solely by the frequency of the light and the makeup of the surface and is independent of the light intensity. This behaviour was puzzling in the context of classical electromagnetic waves, whose energies are proportional to intensity and independent of frequency. Einstein supposed that a minimum amount of energy is required to liberate an electron from a surfaceonly photons with energies greater than this minimum can induce electron emission. This requires a minimum light frequency, in agreement with experiment. Einsteins prediction of the dependence of the kinetic energy of the ejected electrons on the light frequency, based on his photon model, was experimentally verified by the American physicist Robert Millikan in 1916.

In 1922 American Nobelist Arthur Compton treated the scattering of X-rays from electrons as a set of collisions between photons and electrons. Adapting the relation between momentum and energy for a classical electromagnetic wave to an individual photon, p = E/c = hf/c = h/, Compton used the conservation laws of momentum and energy to derive an expression for the wavelength shift of scattered X-rays as a function of their scattering angle. His formula matched his experimental findings, and the Compton effect, as it became known, was considered further convincing evidence for the existence of particles of electromagnetic radiation.

The energy of a photon of visible light is very small, being on the order of 4 1019 joule. A more convenient energy unit in this regime is the electron volt (eV). One electron volt equals the energy gained by an electron when its electric potential is changed by one volt: 1 eV = 1.6 1019 joule. The spectrum of visible light includes photons with energies ranging from about 1.8 eV (red light) to about 3.1 eV (violet light). Human vision cannot detect individual photons, although, at the peak of its spectral response (about 510 nm, in the green), the dark-adapted eye comes close. Under normal daylight conditions, the discrete nature of the light entering the human eye is completely obscured by the very large number of photons involved. For example, a standard 100-watt light bulb emits on the order of 1020 photons per second; at a distance of 10 metres from the bulb, perhaps 1011 photons per second will enter a normally adjusted pupil of a diameter of 2 mm.

Photons of visible light are energetic enough to initiate some critically important chemical reactions, most notably photosynthesis through absorption by chlorophyll molecules. Photovoltaic systems are engineered to convert light energy to electric energy through the absorption of visible photons by semiconductor materials. More-energetic ultraviolet photons (4 to 10 eV) can initiate photochemical reactions such as molecular dissociation and atomic and molecular ionization. Modern methods for detecting light are based on the response of materials to individual photons. Photoemissive detectors, such as photomultiplier tubes, collect electrons emitted by the photoelectric effect; in photoconductive detectors the absorption of a photon causes a change in the conductivity of a semiconductor material.

A number of subtle influences of gravity on light, predicted by Einsteins general theory of relativity, are most easily understood in the context of a photon model of light and are presented here. (However, note that general relativity is not itself a theory of quantum physics.)

Know about the common misconceptions in physics like how gravity affects light, the shape of the earth, and measuring velocity in special relativity

Learn about common physics misconceptions such as how light is affected by gravity and velocity measurements in special relativity.

Through the famous relativity equation E = mc2, a photon of frequency f and energy E = hf can be considered to have an effective mass of m = hf/c2. Note that this effective mass is distinct from the rest mass of a photon, which is zero. General relativity predicts that the path of light is deflected in the gravitational field of a massive object; this can be somewhat simplistically understood as resulting from a gravitational attraction proportional to the effective mass of the photons. In addition, when light travels toward a massive object, its energy increases, and its frequency thus increases (gravitational blueshift). Gravitational redshift describes the converse situation where light traveling away from a massive object loses energy and its frequency decreases.

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light - Quantum theory of light | Britannica