Category Archives: Quantum Physics

Earths magnetic field does way more than guide our compasses and cause occasional worry. Its part of the reason theres life at all on this planetit protects us from harmful solar radiation that might otherwise blow our ozone layer away.

But theres still a lot about the magnetic field scientists dont understand. Most importantly, theyre having trouble figuring out why its so strong. One team decided to take a closer look at the role of the individual elements inside the planet that are thought to influence the field. Turns out, the way nickel behaves at the smallest scales might help explain the magnetic fields strength, to the point that some existing models would need to be rethought. And understanding the Earths magnetic field has implications for everything that relies on it, including activities that require drilling underground.

This is a new idea put into the geophysics research line that nickel has been neglected for the explanation of the geodynamo, the mechanism for creating the magnetic field, study author Giorgio Sangiovanni from the Institute for Theoretical Physics and Astrophysics at the University of Wrzburg in Germany told Gizmodo.

At its most basic level, the Earth probably gets its magnetic field from temperature gradients in the outer core causing metal to convectthis is more or less the way water moves around in a pot of boiling water. Metals can conduct electricity. So, moving metals combined with Earths rotation could create tubes of electric current that point to the poles. Loops of electric current generate magnetic fields through them, so the entire Earth ends up looking like a magnet where the poles align with the tops and bottoms of the tubes.

The problem, which people have been talking about for a while now, is that theres another way for heat to transfer between elements around the core, conduction, that doesnt require metals to physically move. In that case, the energy just gets passed between the atoms as they bump into one another, like how heat travels down the handle of the pot of water youre boiling. But if the outer core loses too much heat through conduction, then theres not enough energy to drive the convection creating the magnetic field. Scientists think that might be the case, and are looking for a source of extra energy that could generate the magnetic field they observe.

Sangiovanni and his colleagues decided to make calculations about the metals in the inner core, to see if they could find some of the missing energy. But unlike the outer core, which is mostly iron, the inner core is 20 percent nickel. The team decided to examine how nickel and irons specific quantum mechanical properties in the Earths solid core impact the magnetic field.

These properties arent fundamental enough to require you to bend over backward imagining Schrdingers cat. They describe the structure of nickel and iron atoms at high temperatures, how electrons interact in collections of these atoms, and how these elements behaviors change at high pressures. It turns out that nickels shape in a solid slows its electrons down. The electrons also interact and scatter off of each other, preventing nickel from being a good conductor of heat, according to the paper published yesterday in Nature Communications. Iron, meanwhile, has a high conductivity at the temperatures and pressures found in the inner core.

In short, the researchers think nickel could reduce the overall conductivity of the core, causing it to retain extra energy that drives convection. And this new insight might have a large enough effect that models of the Earths magnetic field need some reconsidering.

But the researchers findings cant be taken as fact yetthey still need to calculate other properties relating to how nickel conducts heat. But it is promising, said Sangiovanni. Well see after we calculate other important observables, like the thermal and electrical conductivity.

Sangiovanni said that others he spoke to were surprisedmany folks are looking at how lighter elements like silicon influence the physics of Earths core. I would say that people for a long time have discussed the possible presence of nickel in the Earths core, Dario Alf, physics professor at University College, London told Gizmodo, but no one has really discussed it in the way Giorgios paper points out, the effect of nickel on the conductivity of the core.

All that being said, just take solace in the fact that if you dont think you understand the Earths magnetic field, scientists arent completely sure how it works, either.

[Nature Communications]

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Quantum Mechanics Could Shake Up Our Understanding of Earth's ... - Gizmodo

One of the most well-accepted physical theories makes no logical sense. Quantum mechanics, the theory that governs the smallest possible spaces, forces our human brains to accept some really wacky, uncomfortable realities. Maybe we live in a world where certain observations can force our universe to branch into multiple ones. Or maybe actions in the present influence things earlier in time.

A team of physicists did some thinking, and realized this latter idea, called retrocausality, is a consequence of certain interpretations of quantum mechanics, and therefore, certain interpretations of the nature of reality. Their new paper is more of a what-if, an initial look at how to make some of those quantum mechanical interpretations work. Some people I asked thought the work was important, some thought it didnt matter. Others felt their own interpretation of quantum mechanics avoids the problems posed by the new paper. But no matter what, quantum mechanics will force us to make some uncomfortable conclusions about the world.

The foundations of quantum theory are very controversial. We all agree how to use the theory but theres no consensus about the reality it gives us, study author Matthew Leifer from Chapman University told Gizmodo. This is an unusual situation for a theory in physics, since other theories are mostly based on intuitive things we can see and test. Quantum mechanics math, and its predictions, describe the world perfectly, but its sort of impossible to fully grasp whats actually happening beyond the equations.

Quantum mechanics starts with the observation that at the smallest scale, stuff, whether it be light or a piece of an atom, can act simultaneously like a wave and a particle. That means that scientists deal with some level of probability when it comes to tiny things. Send one electron through a pair of parallel slits in a barrier, and youll see it hit the wall behind the barrier like a dot. But if you send many electrons, youll see a striped pattern as if they traveled like a light wave. You cant predict exactly where one electron will hit, but you can create a list of the most likely spots.

Trouble is, describing particles with probabilities leads to some messy stuff. If you have two particles interacting and ones innate physical properties relies on the others, then their associated probabilities, and therefore their identities, are intertwined. As an example, lets say there are two bags, and each has one of two balls, red or green. You give a bag to your friend. Quantum mechanics only gives the probabilities that your bag contains either ball color, and thats all you know before making the observation. At human scales, each bag already contains a red or green ball. But on the particle scale, quantum mechanics says both balls are red and green at the same timeuntil you look.

Thats weird on its own, but it gets worse. If you look at your ball, the other ball automatically takes on the other color. How does the other ball know that you looked? Maybe there is hidden physics, or faster-than-light travel that allows the information to be communicated. One popular interpretation is that we live in a multiverse. In that case, the probabilities dont say anything about the ball, but about which universe we live in. Seeing a certain ball color just means that youre in the universe where your bag had the green ball. In the other universe, you saw a red ball.

Quantum mechanics is weird as hell, where the rules of the world you experience dont apply. Even

So, researchers want to know which of these interpretations is correct. In their new paper, they specifically tackled cases where observing the first ball directly influences the ball in the other bag, through some form of communication. At first glance, this requires information to travel faster than the speed of light. And that sucks, because theres already a theory that says nothing can travel faster than light. But thats okay, say the researchers, if things can influence other things back in time. Forwards in time, Id look at my red ball, then your bag would mysteriously contain a green ball. The retrocausality case says that backwards in time, we already know both ball colors, and my ball must be red because you already knew your ball was green. Then, the balls go hidden into the bag where they become red and green simultaneously. Basically, in this case, you cant run an experiment where you can control for the effects the future has on the past.

This idea of events in the present influencing things in the past is a mathematical consequence of a pair of the authors assumptions. The first assumption is that quantum mechanics should satisfy their definition of time-symmetry, like lots of other physics theories. That means that particles should behave the same way both forward and played in reversea billiard ball hitting a stationary ball looks the same no matter how you play the tape. The theory should also be real, as Leifer says. This means that the particles are more than a list of numbers, but are instead actual things that behave the same yesterday as they will tomorrow, and have properties that are innate, whether or not the experimenter is able to observe them.

Add the math, and according to the new paper published in Proceedings of the Royal Society A this past week, boom. If you want your theory to be time symmetric, and work the same every day, retrocausality is required.

Most would say this is horrible, of course. If things can influence other things in the past, then who cares about all of science? Why test something at all if the result could be causing the cause? Leifer does offer a solutiona sort of block universe, where events in space and time dont cause one another, but instead fit together like a jigsaw puzzle. But this idea hasnt been developed into a mathematical theory, yet.

Basically, if retrocausality is true, then cause-and-effect is an illusion due to the fact that humans only see things in one direction. The paper is only dealing in what-ifs here, and doesnt get into the specifics of how this effect would manifest, aside from in experiments. But the effect would be built into the very fabric of the universe.

Some physicists didnt find this idea compelling. Christopher Fuchs from the University of Massachusetts, Boston told me that these so-called block universes are neither living nor forced nor momentous for me. He takes these terms from the philosopher William James, and means that the hypothesis doesnt sound like a genuine possibility. It doesnt force him to make a decision one way or the other, and essentially, it isnt groundbreaking. In my mind a far more viable path has already been blazed through very different considerations, treating the observer of the universe as the most important agent, and sort of avoiding the impossible-to-observe.

Physicist Sean Carroll from CalTech thought the new paper was interesting, but he happens to like the already-strange many worlds theory, that says different results manifest in different universes described under the same probabilistic description. Thats the one where, in the red/green ball case, there are actually two universes, one where I saw the red ball and one where I saw the green ball. It is perfectly time-symmetric and reversible under the conventional definitions, he said. And it certainly doesnt require retrocausality. So as usual, if you are willing to take seriously the many worlds inside the wave function... much less weirdness is implied by quantum mechanics in other ways. Essentially, hes willing to trade the weirdness of retrocausality for the weirdness of many worlds.

But another expert I spoke with was far more forgiving, and instead thought of this work as an important go/no-go idea for this line of thinking. This paper makes a mathematical statement around retrocausality, said Renato Renner from ETH Zurich in Switzerland. It says maybe we need it if we want time symmetry, a theory that still works if you play the physics in reverse.He thought this paper was one of the first pieces of research make such a well-defined statement about that concept.

So now, researchers have sat and wracked their brains about a solution to a problem that only arises if they assume certain things about the worldin other words, its a new idea, its only a requirement of the universe if you assume certain other things, and its kind of fringe. But as of now, no matter how you want to understand the fabric of the universe, youre going to need to accept something that feels ridiculous, be it a multiverse, faster-than-light communication, or maybe even a world where the future influences the past.

Theres a substantial group of people trying to understand the question of whats really going on, and can we construct a theory based on stuff that really exists out there, said Leifer. The more different approaches we can think of and try out the better.

[Proceedings of the Royal Society A]

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Basic Assumptions of Physics Might Require the Future to Influence ... - Gizmodo

Scientists have successfully teleported something into space for the first time ever.

The experiment saw Chinese scientists send a photon up away from Earth, further than ever before.

Teleportation of this kind uses the bizarre effects of quantum entanglement, rather than physically hurlingthe object itself over distances. Instead it transfers the information about a photon to another point in space creating a faithful replication of the object.

It marks the first ever time that effect has been tested over long distances. The success could bring with it a whole range of uses including a quantum internet that connects different parts of the world atseemingly impossible speed.

Until now, experiments had been restricted to short distances because of problems with the wires or signals that would carry the information.

But the new test saw scientists teleport up to a satellite. That is likely to be the way that such teleportation will work in practice sending objects up to space and then back down again to wherever they are needed, since it means there arerelatively clear paths between all of the different points.

Teleportation has become fairly common on the Earth, where scientists can instantly shoot information about photonsover small distances. But the new study moves towards making that effect more practically useful.

"This work establishes the first ground-to-satellite up-link for faithful and ultra-long-distance quantum teleportation, an essential step toward global-scale quantum internet," the scientists write in their paper, which has been published online.

The satellite itself named Micius after an ancient Chinese philosopher was sent up from the Gobidesert last year, by the team in charge of the project. It dropped off the rocket that carried it to space and it has been in orbit above the Earth ever since.

Micius itself canreceive photons and is sensitive enough to catch and spot them;the team on the ground had kit that could send those photons up into space. Together, that kit could allow the scientists to test how the team on Earth were able to interact with photons floating way above our planet.

It works by harnessing the strange effects of quantum entanglement, which Einstein described as "spooky action at a distance". The effect describes the behaviour where particles seem to act on each other instantly and in bizarre ways.

That entanglement is notconstrained by distances, meaning that two particles can interact despite being a very long way apart. Scientists hope to be able to use that effect for their own ends,includingsending messages that are received far more quickly than using traditional means, for example.

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Scientists teleport particle into space in major breakthrough for quantum physics - The Independent

Quantum physics has spawned its share of strange ideas and hard-to-grasp concepts - from Einsteins spooky action at a distance to the adventures of Shroedingers cat. Now a new study lends support to another mind-bender - the idea of retrocausality, which basically proposes that the future can influence the past and the effect, in essence, happens before the cause.

At this point, retrocausality does not mean that you get to send signals from the future to the past - rather that an experimenters measurement of a particle can influence the properties of that particle in the past, even before making their choice.

The new paper argues that retrocausality could be a part of quantum theory. The scientists expound on the more traditionally accepted concept of time symmetry and show that if that is true, then so should be retrocausality. Time symmetry says that physical processes can run forward and backwards in time while being subject to the same physical laws.

The scientists describe an experiment where time symmetry would require processes to have the same probabilities, whether they go backwards or forward in time. But that would cause a contradiction if there was no retrocausality, as it requires these processes to have different probabilities. What the paper shows is that you cant have both concepts be true at the same time.

Eliminating time symmetry would also get rid of some other sticky problems of quantum physics, like Einsteins discomfort with entanglement which he described as spooky action at a distance. He saw challenges to quantum theory in the idea that entangled or connected particles could instantly affect each other even at large distances. In fact, accepting retrocausality could allow for a reinterpretation of Bell tests that were used to show evidence of spooky action. Instead, the tests could be supporting retrocausailty.

The paper, published in the Proceedings of the Royal Society A, was authored by Matthew S. Leifer at Chapman University in California and Matthew F. Pusey at the Perimeter Institute for Theoretical Physics in Ontario. The scientists hope their work can lead towards a fuller understanding of quantum theory.

"The reason I think that retrocausality is worth investigating is that we now have a slew of no-go results about realist interpretations of quantum theory, including Bell's theorem, Kochen-Specker, and recent proofs of the reality of the quantum state," said Leifer to Phys.org. "These say that any interpretation that fits into the standard framework for realist interpretations must have features that I would regard as undesirable. Therefore, the only options seem to be to abandon realism or to break out of the standard realist framework.

george-musser-explains-spooky-action

Are we going to have time travel as a result of this? In one idea proposed by Richard Feynman,existence of retrocausality could mean that positrons,antimatter counterparts of electrons, would move backwards in time so that they could have a positive charge. If this was proven to be true, time travel could involve simply changing the direction of moving particles in the single dimension of time.

Leifer doesnt go as far as time travel in his explanation, but speculates that if retrocausality does exist in the universe, then there could be evidence of it in the cosmological data, saying that there are certain eras, perhaps near the big bang, in which there is not a definite arrow of causality.

Is this idea ready for the big time? It is supported by Huw Price, a philosophy professor at the University of Cambridge who focuses on the physics of time and is a leading advocate of retrocausality. Leifer and Pusey are taking things in stride, however, realizing that much more work needs to be done.

"There is not, to my knowledge, a generally agreed upon interpretation of quantum theory that recovers the whole theory and exploits this idea. It is more of an idea for an interpretation at the moment, so I think that other physicists are rightly skeptical, and the onus is on us to flesh out the idea, said Leifer.

There are no experiments underway by the physicists to test their theory, but they hope this work will question the assumptions of quantum mechanics and lead to new discoveries down the line.

You can read the study here.

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A New Quantum Theory Predicts That the Future Could Be Influencing the Past - Big Think

Milo Faust, 1, looks at a book from the Baby University series. Courtesy of Amber Faust hide caption

Milo Faust, 1, looks at a book from the Baby University series.

When Kelly Barrales-Saylor was a new mom, she got a lot of children's books as gifts. Most were simple books about shapes, colors and letters. There were none about science or math.

"My editorial brain lit up and said there must be a need for this," says Barrales-Saylor, who works as an editor for a publishing company outside Chicago.

Halfway across the world, Chris Ferrie was similarly unsatisfied.

When reading to his kids, Ferrie noticed that most books used animals to introduce new words. In today's world, that just didn't make sense to him.

"We're not surrounded by animals anymore," says Ferrie, a physicist and mathematician at a university in Sydney, Australia. "We're surrounded by technology." So he created some math and science books for his own children and self-published them online.

That's where Barrales-Saylor found them. And together, they designed a series of books aimed at toddlers and babies.

The books introduce subjects like rocket science, quantum physics and general relativity with bright colors, simple shapes and thick board pages perfect for teething toddlers. The books make up the Baby University series and each one begins with the same sentence and picture This is a ball and then expands on the titular concept.

In the case of general relativity: This ball has mass.

But some of the topics Ferrie covers are tough for even grown-ups to comprehend. (I mean, quantum physics? Come on.)

A firm grasp of rocket science isn't really the point, Barrales-Saylor says.

"We know toddlers aren't going to pick up the exact high-level concepts we're explaining," she says. "We're trying to introduce the small seeds of information meant for them to remember years later."

Some parents hope a happy primer to a complex subject will yield results later on. Take Amber Faust, 33, who lives in South Carolina.

Physics never came easily to her she got a "C" in her college class but that hasn't stopped her from introducing the science to her kids.

She reads Ferrie's Baby University series with sons Oliver, 2, and Milo, 1. Then, they "act it out."

"We make funny noises and run through the house," Faust says. "The 2-year-old is a crazy active baby, so anything we read we have to act out."

Connecting the books to the real world is the best thing parents can do, says Jeff Winokur, an early education and elementary science instructor at Wheelock College in Boston.

"It's important to give kids physical experiences and a chance to talk about them," says Winokur, who remembers learning to dislike science by reading about it.

According to Winokur, what kids and parents need is to accompany their reading with an experiment. It could be as simple as asking the question: "What happens when I roll this ball down a hill?" he says.

Children would do better to engage with physical objects rather than static pictures on a page that way, they bring the subjects to life.

And the idea that physics is incomprehensible to small children? Let's just say, the babies may know more than we think.

"Infants come into the world equipped with expectations that accord very closely to what we consider Newtonian physics," says Kristy vanMarle, who has been researching children's "intuitive physics" at the University of Missouri.

Children as young as 2 months comprehend that objects unsupported will fall and objects hidden will not cease to be, according to vanMarle's study.

"Of course, they can't talk about it, or explain it, but the knowledge in the form of expectations seems to be in place," vanMarle says.

As the children grow, so does their understanding. They learn the language to describe the phenomena they have experienced all their life

In Washington, D.C., Rosie Nathanson is trying to make Ferrie's physics books work for her two younger children.

At her home on Capitol Hill, Nathanson sits on the couch with Henry, 6, and Sylvie, 2 1/2, and reads Rocket Science for Babies:

"This is a ball. This ball is moving."

Henry has been learning about this concept flight in school.

Nathanson continues: "Air can't go through it."

" 'Cause it's aerodynamic," Henry responds. He's excited to hear words he understands.

But while Henry plunges through the books, his little sister grows restless. "I need water," says Sylvie, who's having a hard time grasping this intro to rocket science.

Her mom thinks she might be more interested in the books a year from now. Henry, meanwhile, gives the books a qualified endorsement.

"I like it half and I didn't like it half," says Henry. The half he didn't like? It's "for babies."

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Something New For Baby To Chew On: Rocket Science And ... - NPR - NPR

One of the weirder aspects of quantum mechanics could be explained by an equally weird idea that causation can run backwards in time as well as forwards.

What Einstein called "spooky" action at a distance could theoretically be evidence of retrocausality, which is the particle equivalent of you getting a stomach ache today thanks to tomorrow's bad lunch.

A pair of physicists from the US and Canada took a closer look at some basic assumptions in quantum theory and decided unless we discovered time necessarily ran one way, measurements made to a particle could echo back in time as well as forward.

We all know quantum mechanics is weird. And part of that weirdness comes down to the fact that at a fundamental level, particles don't act like solid billiard balls rolling down a table, but rather like a blurry cloud of possibilities shifting around the room.

This blurry cloud comes into sharp focus when we try to measure particles, meaning we can only ever see a white ball hitting a black one into the corner pocket, and never countless white balls hitting black balls into every pocket.

There is an argument among physicists over whether that cloud of maybes represents something real, or if it's just a convenient representation.

A physicist by the name of Huw Price claimed back in 2012 that if the strange probabilities behind quantum states reflect something real, and if nothing restricts time to one direction, the black ball in that cloud of maybes could theoretically roll out of the pocket and knock the white ball.

"Critics object that there is complete time-symmetry in classical physics, and yet no apparent retrocausality. Why should the quantum world be any different?" Price wrote, paraphrasing the thoughts of most physicists.

Matthew S. Leifer from Chapman University in California and Matthew F. Pusey from the Perimeter Institute for Theoretical Physics in Ontario also wondered if the quantum world might be different when it comes to time.

The pair exchanged some of Price's assumptions and applied their new model to something called Bell's theorem, which is a big deal in this whole spooky action at a distance business.

John Stewart Bell said that the weird things that happen in quantum mechanics can't ever be explained by actions taking place nearby. It's as if nothing is causing the multitude of billiard balls to take such varied paths. At a fundamental level, the Universe is random.

But what about actions taking place somewhere else... or somewhen else? Can something far away influence that cloud without touching it, in a way that Einstein called "spooky"?

If two particles are connected in space at some point, measuring a property of one of them instantly sets the value for the other, no matter where in the Universe it has moved to.

This 'entanglement' has been tested over and over again in light of Bell's theorem, plugging loopholes that might show they are really interacting on a local level in some way, in spite of what seems to be a distance.

As you might guess, the Universe still seems pretty spooky.

But if causality ran backwards, it would mean a particle could carry the action of its measurement back in time to when it was entangled, affecting its partner. No faster-than-light messages needed.

That's the hypothesis Leifer and Pusey were going by.

"There is a small group of physicists and philosophers that think this idea is worth pursuing," Leifer toldLisa Zyga atPhys.org.

By reformulating a few basic assumptions, the researchers developed a model based on Bell's theorem where space was swapped for time. By their reckoning, unless we can show why time must always tick forward, we run into some contradictions.

Needless to say, the idea of retrocausality is a fringe idea.

"There is not, to my knowledge, a generally agreed upon interpretation of quantum theory that recovers the whole theory and exploits this idea. It is more of an idea for an interpretation at the moment, so I think that other physicists are rightly sceptical, and the onus is on us to flesh out the idea."

Now keep in mind, this kind of backwards time travel isn't the sort that would allow you to go back in time and consciously change the present, sorry to say. Future scientists also won't be able to encode lottery numbers into entangled electrons and mail them back to their younger selves.

In any case, the idea of anything trickling backwards in time might not be an appealing one, but let's face it, when it comes to phenomena like entanglement, nearly any explanation is going to sound downright insane.

This research was published in Proceedings of The Royal Society A.

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This quantum theory predicts that the future might be influencing the ... - ScienceAlert

An Alternative to Quantum Entanglement

The quantum world is full of phenomena scientists are still largely grappling with on a theoretical level. One such quantum theory is quantum entanglement. Although there are a number of tests that demonstrate what Einstein called spooky action at a distance, many merelyassume that it happens, without being able to explain how. At least not yet. But two physicists have proposed an alternative that might just be able to explain this quantum effect.

Essentially, quantum entanglement assumes that measurements of quantum properties within thestate of one entangled particle occurs simultaneously withits entangled pair, regardless of how far apart they are. There isnt any known mechanism that would explain that kind of influence, though, which is why physicists Matthew S. Leifer at Chapman University and Matthew F. Pusey at the Perimeter Institute for Theoretical Physics have offered an alternative: the team has asserted theidea of retrocausality as a possible explanation for this spooky action. Theirfindings werepublished in the journal Proceedings of The Royal Society Ain June.

There is a small group of physicists and philosophers that think this idea is worth pursuing, including Huw Price and Ken Wharton [a physics professor at San Jos State University], Leifer told Phys.org. There is not, to my knowledge, a generally agreed upon interpretation of quantum theory that recovers the whole theory and exploits this idea. It is more of an idea for an interpretation at the moment, so I think that other physicists are rightly skeptical, and the onus is on us to flesh out the idea.

Simply stated, retrocausality assumes that influences can travel backwards in time. When an experimenter decides how to measure a particle, that choice can influence the properties of that particle or,an entangled particle in the past. This, therefore, makes the action at a distance part of Einsteins definition unnecessary. Instead, the entanglement effect becomes retrocausal influence. That being said, its not the same thing as sending signals back in time.

Retrocausal theory, then, could offer a better quantum theory. The only options seem to be to abandon realism or to break out of the standard realist framework, Leifer explained. Abandoning realism is quite popular, but I think that this robs science of much of its explanatory power and so it is better to find realist accounts where possible. Retrocausality entails a number of assumptions, though:including one that reformulates the idea of time symmetry.

At any rate, Leifer and Pusey think that retrocausality can offer a generalized standard quantum theory. This might be needed to construct the correct theory of quantum gravity, or even to resolve some issues in high-energy physics given that the unification of the other three forces is still up in the air in the light of LHC results, Leifer added. Perhaps it could even help improve quantum computing technology.

Needless to say, as is the case with most everything in the world of quantum physics, the work is largely theoretical. As far as direct experimental tests of retrocausality go, the status is not much different from other things in the foundations of quantum mechanics, Leifer said. We never test one assumption in isolation, but always in conjunction with many others, and then we have to decide which one to reject on other grounds.

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Physicists May Have Discovered One of the Missing Pieces of Quantum Theory - Futurism

New theoretical evidence may show an influence on time, proving that the field of quantum physics can be an incredibly tricky place.

Quantum physics can be confusing to the point of a headache.

To be fair, there are a lot of unknowns when it comes to quantum physics. Weve been studying it since the days of Einstein, and by all accounts, we have barely scratched the surface.

One debate in the field is centered around an idea called retrocausality, something many physicists remain skeptical of. You cant blame them, Einstein himself described the property as spooky. If we learned anything from Scooby Doo, its that spooky things can be a lot of trouble.

Recently, the journal Proceedings of The Royal Society published a paper by physicists Matthew S. Leifer and Matthew F. Pusey regarding retrocausality. The paper gives some theoretical support for retrocausal elements of quantum theory, something which might pique the interest of physicists everywhere.

So, lets clear up the concept of retrocausality because it can get pretty confusing.

An influence cant go back in time due to thermodynamic reasons, but that doesnt mean that the past cant be influenced. With retrocausality, a measurement made in the present can influence the properties of a particle in the past.

Previously, retrocausality didnt have a lot of theoretical support. For most, the famous Bell tests didnt deal in retrocausal influences. For Leifer and Pusey, however, the Bell tests can be interpreted as evidence for retrocausality.

The Bell tests were meant to show the existence of entanglement. It showed that there were unknown properties that allowed for action-at-a-distance. With Leifer and Puseys research, there is a new theory thrown into the hat.

Just allow for the possibility that the measurement of one particle can retrocausally influence another, and you dont need action-at-a-distance. You just need retrocausality.

Mind you, were talking about a field where much is still unknown, so Leifer and Pusey are only convinced that these are potential interpretations rather than facts. That being said, if this research helps us fill in some of the unknowns behind quantum physics, then it is a step in the right direction.

If retrocausality is an element of quantum physics, it will ripple through the entire foundation of quantum theory.

But that might be a good thing because we dont completely understand quantum theory. Retrocausality wont show us the entire picture, but it is one more puzzle piece that we didnt have before.

The research seems to imply that different interpretations of quantum physics are in order. According to Leifer, This might be needed to construct the correct theory of quantum gravity, or even to resolve some issues in high-energy physics given that the unification of the other three forces is still up in the air in the light of LHC results.

So far, there is no word on any actual experimentation to test retrocausality. Instead, it might be more valuable to apply it existing models within quantum physics. That way we can see if it helps to explain those models in theory.

And there is plenty of data for that task. With the amount of information we are getting from the large hadron collider over at CERN, researchers may have all the data they need.

So, it isnt quite the flux capacitor we were all hoping for, but the edge of quantum physics is still showing us some mind-bending stuff. If you want more details, click here.

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Quantum Physics Provide Evidence that the Future Influences the Past - Edgy Labs (blog)

Posted July 06, 2017 17:20:11

At what age should your kids start learning about science?

For Dr Chris Ferrie, a senior lecturer in quantum physics at the University of Technology, Sydney, no child is too young.

Dr Ferrie bills himself as a scientist by day and father by night, who occasionally moonlights as a children's book author.

He has written multiple children's books on subjects ranging from relativity to rocket science after noticing there were not many science books for kids in bookstores.

In 2015, Dr Ferrie reached internet fame when Facebook founder Mark Zuckerberg was pictured reading one of his books, Quantum Physics for Babies, to his young daughter.

With his new book, Goodnight Lab a playful rewriting of children's classic Goodnight Moon he hopes to spark an early interest in science and technology.

"The point of books is to make sure that that variety is out there so that every possible topic that someone might be interested in is represented," Dr Ferrie said.

The father of four does not accept that big words like voltmeter and liquid nitrogen should be banished from books for children.

"I doubt any of them are ever going to see an elephant and that has many syllables, yet they all seem to know what an elephant is and what it sounds like and what it does.

"They'll certainly see scientific instruments. Many of them will miniaturised and inside of a phone, but they're there."

Despite all the attention, Dr Ferrie cannot see himself giving away his career as a researcher any time soon.

"I enjoy my research, it's my real passion. If I was employed as a book author, I think I would stop writing books," he said.

"I do it because it's sort of a hobby and if it became my livelihood, then it wouldn't be as exciting as it is now."

Sunita Oberholzer and her three young boys are fans of Dr Ferrie's work.

"The youngest really loves maths and they love science," Ms Oberholzer said.

"We went to Questacon in Canberra, which they didn't want to leave they could have spent the whole day there.

"They definitely enjoy it even if they don't know it's science that they're looking at."

Ms Oberholzer said she cannot see any reason why children should not be exposed to scientific concepts from a young age.

"I mean, you talk about whether things are heavy or light, or things floating in the bath," she said.

"Uou can do that when they're babies really."

Even if children do not quite understand the science, many like 10-year-old Finn Warner simply enjoy engaging in it.

"Goodnight liquid nitrogen, goodnight compressed air, goodnight scientists everywhere," he said, reading from the book.

"I don't know all of [the words], I don't know what spectrometer means. It's quite funny."

Topics: science, children, science-and-technology, human-interest, sydney-2000, australia

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How young is too young to talk to kids about science? Never, says one quantum physicist - ABC Local

July 4, 2017 by Lea Kivivali Credit: Swinburne University of Technology

By gently prodding a swirling cloud of supercooled lithium atoms with a pair of lasers, and observing the atoms' response, researchers at Swinburne have developed a new way to probe the properties of quantum materials.

Quantum materialsa family that includes superfluids, superconductors, exotic magnets, ultracold atoms and recently-discovered 'topological insulators'display on a large scale some of the remarkable quantum effects usually associated with microscopic and subatomic particles.

But, while quantum mechanics explains the behaviour of microscopic particles, applying quantum theory to larger systems is far more challenging.

"While the potential of quantum materials, such as superconductors, is undeniable, we need to fully grasp the underlying quantum physics at play in these systems to establish their true capabilities," says Chris Vale, an Associate Professor at the Centre for Quantum and Optical Science, who led the research. "That's a big part of the motivation for what we do."

Associate Professor Vale and his colleagues, including Sascha Hoinka and Paul Dyke, also at Swinburne, developed a new way to explore the behaviour of this family of materials. They detected when a 'Fermi gas' of lithium atoms, a simple quantum material, entered a quantum 'superfluid' state.

New system checks theories against experiment

Their system allows theories of superconductivity and related quantum effects to be precisely checked against experiment, to see whether the theories are accurate and how they could be refined.

The researchers' advance was based on the fact that quantum materials' special properties emerge when their constituent particles enter a synchronised state. The zero-resistance flow of electrons through superconductors, for example, emerges when electrons can team up to form 'Cooper pairs'.

The team's sophisticated experimental set-up allowed this co-ordinated quantum behaviour to be detected. By fine-tuning the interaction of their lasers with the Fermi gas, Associate Professor Vale and his colleagues were for the first time able to detect the elusive, low energy Goldstone mode, an excitation that only appears in systems that have entered a synchronised quantum state.

"Because our experiment provides a well-controlled environment and the appearance of the Goldstone mode is very clear, our measurements provide a benchmark that quantum theories can be tested against before they're applied to more complex systems like superconductors," Associate Professor Vale says.

"By developing methods to understand large systems that behave quantum mechanically, we're building the knowledge base that will underpin future quantum-enabled technologies."

The team's research has been published in the online journal Nature Physics.

Explore further: Frequency modulation accelerates the research of quantum technologies

More information: Sascha Hoinka et al. Goldstone mode and pair-breaking excitations in atomic Fermi superfluids, Nature Physics (2017). DOI: 10.1038/nphys4187

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Supercool breakthrough brings new quantum benchmark - Phys.org - Phys.Org