Daily Archives: August 15, 2022

(09:20) And then we have a bunch of matter fields, they come in three groups of four. The most familiar ones are an electron field, two quark fields associated to the up and the down quark. The proton contains oh man, I hope we get this right two up and down and the neutron contains two down and an up, I think, Ive got that the right way around.

Strogatz (09:41): You could fool me either way. I can never remember.

Tong (09:43): Yeah, but the listeners are gonna know. And then a neutrino field. So theres this collection of four particles interacting with three forces. And then for a reason that we really do not understand, the universe decided to repeat those matter fields twice over. So there is a second collection of four particles called the muon, the strange the charm and another neutrino. We sort of ran out of good names for neutrinos, so we just call it the muon neutrino. And then you get another collection of four: the tau, the top quark, the bottom quark and, again, a tau neutrino. So nature has this way of repeating itself. And no one really knows why. I think that remains one of the big mysteries. But those collections of 12 particles interacting with three forces comprises the Standard Model.

(09:43) Oh, and I missed one. The one I missed is important. Its the Higgs boson. The Higgs boson sort of ties everything together.

Strogatz (10:37): All right, thats tantalizing. Maybe we should say a little what the Higgs boson does, what role does it play in the Standard Model.

Tong (10:43): It does something rather special. It gives a mass to all the other particles. I would love to have a good analogy to explain how it gives mass. I can give a bad analogy, but it really is a bad analogy. The bad analogy is that this Higgs field is spread throughout all of space, thats a true statement. And the bad analogy is it acts a little like treacle or molasses. The particles sort of have to push their way through this, this Higgs field to make any progress. And that sort of slows them down. They would naturally travel at the speed of light, and they get slowed down by the presence of this Higgs field. And that is responsible for the phenomenon that we call mass.

(11:22) A large part of what I just said is basically a lie. I mean, it sort of suggests that theres some friction force at play. And thats not true. But its one of those things where the equations are actually surprisingly easy. But its rather hard to come up with a compelling analogy that captures those equations.

Strogatz (11:36): Its an amazing statement that you made, that without the Higgs field or some, I guess, some analogous mechanism, everything would be moving at the speed of light. Did I hear you right?

Tong (11:47): Yes, except, as always, these things, its yes, with a caveat. The but is if the Higgs field turned off, the electron would move at the speed of light. So you know, atoms would not be particularly stable. The neutrino, which is almost massless anyway, would travel at the speed of light. But the proton or neutron, it turns out, would have basically the same masses that they have now. You know, the quarks inside them would be massless. But the mass of the quarks inside the proton or neutron, are totally trivial compared to the proton or neutron 0.1%, something like that. So the proton or neutron actually get their mass from a part of quantum field theory that we understand least, but wild fluctuations of quantum fields, is whats going on inside the proton or neutron and giving them their mass. So the elementary particles would become massless quarks, electrons but the stuff were made of neutrons and protons would not. They get their mass from this other mechanism.

Strogatz (12:42): Youre just full of interesting things. Lets see if I can say what Im thinking in response to that. And you can correct me if Ive got it completely wrong. So Ive got these strongly interacting quarks inside, say, a proton. And I keep in my mind guessing theres some E = mc2 connection going on here, that the powerful interactions are associated with some large amount of energy. And thats somehow translating into mass. Is it that, or is that theres virtual particles being created and then disappearing? And all of that is creating energy and therefore mass?

Tong (13:16): Its both of the things you just said. So we tell this lie when were in high school physics is all about telling lies when youre young and realizing that things are a bit more complicated as you grow older. The lie we tell, and I already said it earlier, is that there are three quarks inside each proton and each neutron. And its not true. The correct statement is that there are many hundreds of quarks and antiquarks and gluons inside a proton. And statement that there are really three quarks, the proper way of saying it is that at any given time, there are three more quarks than there are antiquarks. So theres sort of an additional three. But its an extraordinarily complicated object, the proton. It, its nothing nice and clean. It contains these hundreds, possibly even thousands of different particles interacting in some very complicated way. You could think about these quark-antiquark pairs as being, as you say, virtual particles, things that just pop out of the vacuum and pop back in again inside the proton. Or another way of thinking about it is just the fields themselves are excited in some complicated fashion inside the proton or neutron thrashing around and thats whats giving them their mass.

Strogatz (14:20): Earlier, I hinted that this is a very successful theory and mentioned something about 12 decimal places. Can you tell us about that? Because that is one of the great triumphs, I would say not just of quantum field theory, or even physics, but all of science. I mean, humanitys attempt to understand the universe, this is probably the best thing weve ever done. And from a quantitative standpoint, we as a species.

Tong (14:42): I think thats exactly right. Its kind of extraordinary. I should say that theres a few things we can calculate extraordinarily well, when we know what were doing, we can really do something spectacular.

Strogatz (14:42): Its enough to get you sort of in a philosophical mood, this question of the unreasonable effectiveness of mathematics.

Tong (14:52): So, the particular object or the particular quantity, that is the poster boy for quantum field theory, because we can calculate it very well albeit taking many, many decades to do these calculations, theyre not easy. But also importantly, we can measure it experimentally very well. So its a number called g-2 , its not particularly important in the grand scheme of things, but the number is the following. If you take an electron, then it has a spin. The electron spins about some axis not dissimilar to the way the Earth spins about its axis. Its more quantum than that, but its not a bad analogy to have in mind.

(14:59) And if you take the electron, and you put it in a magnetic field, the direction of that spin precesses over time, and this number g-2 just tells you how fast it precesses, the -2 is slightly odd. But you would naively think that this number would be 1. And [Paul] Dirac won the Nobel Prize in part for showing that actually this number is 2 to first approximation. Then [Julian] Schwinger won the Nobel Prize, together with [Richard] Feynman and [Sin-Itiro] Tomonaga, for showing that, you know, its not 2, its 2-point-something-something-something. Then over time, weve made that something-something-something with another nine somethings afterwards. As you said, its something that we now know extremely well theoretically and extremely well experimentally. And its just astonishing to see these numbers, digit after digit, agreeing with each other. Its something rather special.

(15:21) This is one of the things that pushes you in that direction is that its so good. Its so good that this isnt a model for the world, this is somehow much closer to the actual world, this equation.

Strogatz (16:31): So having sung the praises of quantum field theory, and it does deserve to be praised, we should also recognize that its an extremely complicated, and in some ways, problematic theory or set of theories. And so in this part of our discussion, I wonder if you could help us understand what reservation should we have? Or where the frontier is. Like, the theory is said to be incomplete. What is incomplete about it? What are the big remaining mysteries about quantum field theory?

Tong (17:01): You know, it really depends on what you subscribe to. If youre a physicist and you want to compute this number g-2, then theres nothing incomplete about quantum field theory. When the experiment gets better, you know, we calculate or we do better. You can really do as well as you want to. Theres several axes to this. So let me maybe focus on one to begin with.

(17:22) The problem comes when we talk to our pure mathematician friends, because our pure mathematician friends are smart people, and we think that we have this mathematical theory. But they dont understand what were talking about. And its not their fault, its ours. That the mathematics were dealing with is not something thats on a rigorous footing. Its something where were playing sort of fast and loose with various mathematical ideas. And were pretty sure we know what were doing as this agreement with experiments shows. But its certainly not at the level of rigor that, well, certainly mathematicians would be comfortable with. And I think increasingly that we physicists are also growing uncomfortable with.

(17:22) I should say that this isnt a new thing. Its always the case whenever there are new ideas, new mathematical tools, that often the physicists take these ideas and just run with them because they can solve things. And the mathematicians are always they like the word rigor, maybe the word pedantry is better. But now, theyre kind of going slower than us. They dot the is and cross the Ts. And somehow, with quantum field theory, I feel that, you know, its been so long, theres been so little progress that maybe were thinking about it incorrectly. So thats one nervousness is that it cant be made mathematically rigorous. And its not through want of trying.

Strogatz (18:33): Well, lets try to understand the nub of the difficulty. Or maybe there are many of them. But you spoke earlier about Michael Faraday. And at each point in space, we have a vector, a quantity that we could think of as an arrow, its got a direction and a magnitude, or if we prefer, we could think of it as three numbers maybe like an x, y and z component of each vector. But in quantum field theory, the objects defined at each point are, I suppose, more complicated than vectors or numbers.

Tong (18:33): They are. So the mathematical way of saying this is that at every single point, there is an operator some, if you like, infinite dimensional matrix that sits at each point in space, and acts on some Hilbert space, that itself is very complicated and very hard to define. So the mathematics is complicated. And in large part, its because of this issue that the world is a continuum, we think that space and time, space in particular, is continuous. And so you have to define really something at each point. And next to one point, infinitesimally close to that point is another point with another operator. So theres an infinity that appears when you look on smaller and smaller distance scales, not an infinity going outwards, but an infinity going inwards.

(19:44) Which suggests a way to get around it. One way to get around it is just to pretend for these purposes, that space isnt continuous. In fact, it might well be that space isnt continuous. So you could imagine thinking about having a lattice, what mathematicians call a lattice. So rather than have a continuous space, you think about a point, and then some finite distance away from it, another point. And some finite distance away from that, another point. So you discretize space, in other words, and then you think about what we call the degrees of freedom, the stuff that moves as just living on these lattice points rather than living in some continuum. Thats something that mathematicians have a much better handle on.

(19:44) But theres a problem if we try to do that. And I think its one of the deepest problems in theoretical physics, actually. Its that some quantum field theories, we simply cannot discretize in that way. There is a mathematical theorem that forbids you from writing down a discrete version of certain quantum field theories.

Strogatz (20:41): Oh, my eyebrows are raised at that one.

Tong (20:43): The theorem is called the Nielsen-Ninomiya theorem. Among the class of quantum field theories that you cannot discretize is the one that describes our universe, the Standard Model.

Strogatz (20:52): No kidding! Wow.

Tong (20:54): You know, if you take this theorem at face value, its telling us were not living in the Matrix. The way you simulate anything on a computer is by first discretizing it and then simulating. And yet theres a fundamental obstacle seemingly to discretizing the laws of physics as we know it. So we cant simulate the laws of physics, but it means no one else can either. So if you really buy this theorem, then were not living in the Matrix.

Strogatz (21:18): Im really enjoying myself, David. This is so, so interesting. I never had a chance to study quantum field theory. I did get to take quantum mechanics from Jim Peebles at Princeton. And that was wonderful. And I did enjoy that very much, but never continued. So quantum field theory, Im just in the position of many of our listeners here, just looking in agog at all the wonders that youre describing,

Tong (21:41): I can tell you a little more about the exact aspect of the Standard Model that makes it hard or impossible to simulate on a computer. Theres a nice tagline, I can add like a Hollywood tagline. The tagline is, Things can happen in the mirror that cannot happen in our world. In the 1950s, Chien-Shiung Wu discovered what we call parity violation. This is the statement that when you look at something happening in front of you, or you look at its image in a mirror, you can tell the difference, you can tell whether it was happening in real world or happening in the mirror. Its this aspect of the laws of physics, that what happens reflected in a mirror is different from what happens in reality, that turns out to be problematic. Its that aspect thats difficult or impossible to simulate, according to this theory.

Strogatz (22:28): Its hard to see why I mean, because the lattice itself wouldnt have any problem coping with the parity. But anyway, Im sure its a subtle theorem.

Tong (22:36): I can try to tell you a little bit about why every particle in our world electrons, quarks. They split into two different particles. Theyre called left-handed and right-handed. And its basically to do with how their spin is changing as they move. The laws of physics are such that the left-handed particles feel a different force from the right-handed particles. This is what leads to this parity violation.

(22:59) Now, it turns out that its challenging to write down mathematical theories that are consistent and have this property that left-handed particles and right-handed particles, experienced different forces. There are sort of loopholes that you have to jump through. Its called anomalies, or anomaly cancellation in quantum field theory. And these subtleties, these loopholes they come from, at least in certain ways of calculating the fact that space is continuous, you only see these loopholes when spaces, or these requirements when space is continuous. So the lattice knows nothing about this. The lattice knows nothing about these fancy anomalies.

(23:36) But you cant write down an inconsistent theory on the lattice. So somehow, the lattice has to cover its ass, it has to make sure that whatever it gives you is a consistent theory. And the way it does that is just by not allowing theories where left-handed and right-handed particles feel different forces.

Strogatz (23:50): All right, I think I get the flavor of it. Its something like that topology allows for some of the phenomena, these anomalies that are required to see what we see in the case of the weak force, that a discrete space would not permit. That something about the continuum is key.

Tong (24:06): You said it better than me, actually. Its all to do with topology. Thats exactly right. Yeah.

Strogatz (24:11): All right. Good. Thats a very nice segue for us actually, into where I was hoping we could go next, which is to talk about what quantum field theory has done for mathematics, because that is another one of the great success stories. Although, you know, for physicists who care about the universe, thats maybe not a primary concern, but for people in, in mathematics, were very grateful and also mystified at the great contributions that have been made by thinking about purely mathematical objects, as if they were informing them with insights from quantum field theory. Could you just tell us a little about some of that story starting, say, in the 1990s?

Tong (24:48): Yeah, this is really one of the wonderful things that come out of quantum field theory. And theres no small irony here. You know, the irony is that were using these mathematical techniques that mathematicians are extremely suspicious about because they dont think that, that theyre, theyre not rigorous. And yet at the same time, were sort of somehow able to leapfrog mathematicians and almost beat them at their own game in certain circumstances, where we can turn around and hand them results that theyre interested in, in their own area of specialty, and results that in some circumstances have utterly transformed some areas of mathematics.

(25:22) So I can try to give you some sense about how this works. The kind of area of mathematics that this has been most useful in is ideas to do with geometry. Its not the only one. But its, I think its the one that weve made most progress in thinking about as physicists. And of course, geometry has always been close to the heart of physicists. Einsteins theory of general relativity is really telling us that space and time are themselves some geometric object. So that what we do is we take what mathematicians call a manifold, its some geometric space. In your mind, you can think, firstly, of the surface of a soccer ball. And then maybe if the surface of a doughnut, where theres a hole in the middle. And then generalize to the surface of a pretzel, where theres a few holes in the middle. And then the big step is to take all of that and push it to some higher dimensions and think of some higher dimensional object with wrapped around on itself with higher dimensional holes, and, and so on.

(26:13) And so the kinds of questions mathematicians are asking us to classify objects like this, to ask whats special about different objects, what kind of holes they can have, the structures they can have on them, and so forth. And as physicists, we sort of come with some extra intuition.

(26:28) But in addition, we have this secret weapon of quantum field theory. We sort of have two secret weapons. We have quantum field theory; we have a willful disregard for rigor. Those two combine quite, quite nicely. And so we will ask questions like, take one of these spaces, and put a particle on it, and ask how does that particle respond to the space? Now with the particles or quantum particles, something quite interesting happens because it has a wave of probability which spreads over the space. And so because of this quantum nature, it has the option to sort of know about the global nature of the space. It can sort of feel out all of the space at once and figure out where the holes are and where the valleys are and where the peaks are. And so our quantum particles can do things like get stuck in certain holes. And in that way, tell us something about the topology of the spaces.

(27:18) So theres been a number of very major successes of applying quantum field theory to this one of the biggest ones was in the early 1990s, something called mirror symmetry, which revolutionized an area called symplectic geometry. A little later [Nathan] Seiberg and [Edward] Witten solved a particular four-dimensional quantum field theory, and that gave new insights into topology of four-dimensional spaces. Its really been a wonderfully fruitful program, where whats been happening for several decades now is physicists will come up with new ideas from quantum field theory, but utterly unable to prove them typically, because of this lack of rigor. And then mathematicians will come along, but its not just dotting eyes and crossing Ts, they typically take the ideas and they prove them in their own way, and introduce new ideas.

(28:02) And those new ideas are then feeding back into quantum field theory. And so theres been this really wonderful harmonious development between mathematics and physics. As it turns out, that were often asking the same questions, but using very different tools, and by talking to each other have made much more progress than we otherwise would have done.

Strogatz (28:18): I think the intuitive picture that you gave is very helpful that somehow thinking about this concept of a quantum field as something that is delocalized. You know, rather than a particle that we think of as point-like, you have this object that spreads over the whole of space and time, if theres time in the theory, or if were just doing geometry, I guess were just thinking of it as spreading over the whole of the space. These quantum fields are very neatly suited to detecting global features, as you said.

(28:47) And thats not a standard way of thinking in math. Were used to thinking a point and the neighborhood of a point, the infinitesimal neighborhood of a point. Thats our friend. Were like the most myopic creatures as mathematicians, whereas the physicists are so used to thinking of these automatically global sensing objects, these fields that can, as you say, sniff out the contours, the valleys, the peaks, the wholes of surfaces of global objects.

Tong (29:14): Yeah, thats exactly right. And part of the feedback into physics has been very important. So appreciating that topology is really underlying a lot of our ways of thinking in quantum field theory that we should think globally in quantum field theory as well as in, in geometry. And, you know, there are programs, for example, to build quantum computers and one of the most, well, perhaps its one of the more optimistic ways to build quantum computers.

(29:34) But if it could be made to work, one of the most powerful ways of building a quantum computer is to use topological ideas of quantum field theory, where information isnt stored in a local point but its stored globally over a space. The benefit being that if you nudge it somewhere at a point, you dont destroy the information because its not stored at one point. Its stored everywhere at once. So as I said, theres this really this wonderful interplay between mathematics and physics that Its happening as we speak.

Strogatz (30:01): Well, lets shift gears one last time back away from mathematics toward physics again, and maybe even a little bit of cosmology. So with regard to the success story of the physical theory, more of the constellation of theories that we call quantum field theory, weve had these experiments fairly recently at CERN. Is this, thats where the Large Hadron Collider is, is that right?

Tong (30:01): Thats right. Its in Geneva.

Strogatz (30:04): Okay. You mentioned about the discovery of the Higgs long predicted something like 50, 60 years ago, but its my understanding that physicists have been well, whats the right word? Disappointed, chagrined, puzzled. That some of the things that theyd hoped to see in the experiments at the Large Hadron Collider have not materialized. Supersymmetry, say, being one. Tell us a little about that story. Where are we hoping to see more from those experiments? How should we feel about not seeing more?

Tong (30:53): We were hoping to see more. I have no idea how we should feel though, that we havent seen. I could, I can tell you the story.

Tong (31:00): So the LHC was built. And it was built with the expectation that it would discover the Higgs boson, which it did. The Higgs boson was the last part of the Standard Model. And there were reasons to think that once we completed the Standard Model, the Higgs boson would also be the portal that led us to what comes next, the next layer of reality that what comes afterwards. And there are arguments that you can make, that when you discover the Higgs, you should discover sort of around in the same neighborhood, the same energy scale as the Higgs, some other particles that somehow stabilize the Higgs boson. The Higgs boson is special. Its the only particle in the Standard Model that doesnt spin. All other particles, the electron spins, the photon spins, its what we call the polarization. The Higgs boson is the only particle that doesnt spin. In some sense, its the simplest particle in the Standard Model.

(31:00) But there are arguments theoretical arguments that say that a particle that doesnt spin should have a very heavy mass. Very heavy means pushed up to the highest energy scale possible. These arguments are good arguments. We could use quantum field theory in many other situations, in materials described by quantum field theory. Its always true that if a particle doesnt spin, its called a scalar particle. And its got a light mass. Theres a reason why its masses light.

(32:25) And so we expected there to be a reason why the Higgs boson had the mass that it has. And we thought that reason would come with some extra particles that will sort of appear once the Higgs appeared. And maybe it was supersymmetry and maybe it was something called technicolor. And there were many, many theories out there. And we discovered the Higgs and the LHC I think this is important to add has exceeded all expectations when it comes to the operation of the machine and the experiments and the sensitivity of the detectors. And these people are absolute heroes who are doing the experiment.

(32:56) And the answer is theres just nothing else there at the energy scale that were currently exploring. And thats a puzzle. Its a puzzle to me. And its a puzzle to many others. We were clearly wrong; we were clearly wrong about the expectation that we should discover something new. But we dont know why were wrong. You know, we dont know what was wrong with those arguments. They still feel right, they still feel right to me. So theres something that were missing about quantum field theory, which is exciting. And you know, its good to be wrong in this area of science, because its only when youre wrong, you can finally be pushed in the right direction. But its fair to say that were not currently sure why were wrong.

Strogatz (33:32): Thats a good attitude to have, right, that so much progress has been made from these paradoxes, from what feels like disappointments at the time. But to be living through it and to be in a generation I mean, well, I dont want to say you could be washed up by the time this is figured out, but its a scary prospect.

Tong (33:50): Washed up would be fine. But Id like to be alive.

Strogatz (33:56): Yeah, I felt bad even saying that.

Going from the small to the big, why dont we think about some of the cosmological issues. Because some of the other great mysteries, things like dark matter, dark energy, the early universe. So you study as one of your own areas of great interest, the time right after the Big Bang, when we didnt really have particles yet. We just had, what, quantum fields?

Tong (34:22): There was a time after the Big Bang called inflation. So it was a time at which the universe expanded very, very rapidly. And there were quantum fields in the universe when this was happening. And what I think is really one of the most astonishing stories in all of science is that these quantum fields had fluctuations. Theyre always bouncing up and down, just because of quantum jitters, you know. Just as the Heisenberg uncertainty principle says a particle cant, cant be in a specific place because it will have infinite momentum, so you know, its always some uncertainty there. That the same is true for these fields. These quantum fields cant be exactly zero or exactly some value. Theyre always jittering up and down through quantum uncertainty.

(35:02) And what happened in these first few seconds seconds is way too long. First few 10-30 seconds, lets say, of the Big Bang is the universe expanded very rapidly. And these quantum fields sort of got caught in the act, that they were fluctuating, but then the universe dragged them apart to vast scales. And those fluctuations got stuck there. They couldnt fluctuate anymore, basically, because of causality reasons, because now they were spread so far that, you know, one part of the fluctuation didnt know what the other one was doing. So these fluctuations get stretched across the whole universe, way back in the day.

(35:43) And the wonderful story is that we can see them, we can see them now. And weve taken a photograph of them. So the photograph has a terrible name. Its called the cosmic microwave background radiation. You know this photograph, its the blue and red ripples. But its a photograph of the fireball that filled the universe 13.8 billion years ago, and theres ripples in there. And the ripples that we can see were seeded by these quantum fluctuations in the first few fractions of a second after the Big Bang. And we can do the calculation, you can calculate what the quantum fluctuations look like. And you can experimentally measure the fluctuations in the CMB. And they just agree. So its an astonishing story that we can take a photograph of these fluctuations.

(36:30) But theres also a level of disappointment here as well. The fluctuations that we see are fairly vanilla, theyre just those that you would get from free fields. And it would be nice if we could get more information, if we could see the statistical name is that the fluctuations are Gaussian. And it would be nice to see some non-Gaussianity, which will be telling us about the interactions between the fields back in the very, very early universe. And so again, the Planck satellite has, has flown and it has taken a snapshot of the CMB in ever clearer detail, and the non-Gaussianities that are there, if there are any there at all, are just smaller than, than the Planck satellite can detect.

(36:52) So theres hope for the future that theres other CMB experiments, theres also a hope that these non-Gaussianities might show up in the way that galaxies form, the statistical distribution of galaxies through the universe also holds a memory of these fluctuations that much we know is true, but that perhaps we might get more information from there. So it really is incredible that you can trace these fluctuations for 14 billion years, from the very earliest stages to the way the galaxies are distributed in the universe now,

Strogatz (37:36): Well, thats given me a lot of insight that I didnt have before about the imprint of these quantum fluctuations on the cosmic microwave background. Id always wondered. You mentioned that its the free theory, meaning what, tell us whats free means exactly? Theres no nothing right? I mean, its just, its the vacuum itself?

Tong (37:45): Its not just the vacuum, because these fields get excited as the universe expands. But its just a field that isnt interacting with any other fields or even with itself, its just bouncing up and down like a harmonic oscillator, basically. Each point is bouncing up and down like a spring. So its kind of the most boring field that you could imagine.

Strogatz (38:11): And so that means we didnt have to postulate any particular quantum field at the beginning of the universe. Its just, thats what you say, vanilla.

Tong (38:19): Its vanilla. So it would have been nice to get a better handle that these interactions are happening, or these interactions are happening, or the field had this particular property. And that doesnt seem maybe in the future, but at the moment, were not there yet.

Strogatz (38:32): So maybe we should then close with your personal hopes. Is there one, if you had to single out one thing that you would like to see solved personally, in the next few years, or for the future of research in quantum field theory, what would be your favorite? If you could dream.

Tong (38:48): There are so many

Strogatz: You can pick more.

Tong: Theres things on the mathematical side. So I would, I would love to understand, on the mathematical side, more about this Nielsen-Ninomiya theorem, the fact that you cannot discretize certain quantum field theories. And are there loopholes in the theorem? Are there assumptions we can throw out and somehow succeed in doing it?

(39:07) You know, theorems in physics, theyre usually called no-go theorems. You cant do this. But theyre often signposts about where you should look, because a mathematical theorem is, obviously its true, but therefore, it comes with very strict assumptions. And so maybe you can throw out this assumption or that assumption and, and make progress on that. So its on the mathematical side, I would love to see progress on that.

(39:28) On the experimental side, any of the things that weve spoken about some new particle, new hints of what lies beyond. And we are seeing hints fairly regularly. The most recent one is that the mass of the W boson on your side of the Atlantic is different from the mass of the W boson on my side of the Atlantic and that, that seems weird. Hints about dark matter, or dark matter. Whatever it is, is made of quantum fields. Theres no doubt about that.

(39:53) And the dark energy that you alluded to that there are predictions is too strong a word but there are suggestions from quantum field theory. at all those fluctuations of quantum fields should be driving the expansion of the universe. But in a way thats way, way bigger than were actually seeing.

(40:07) So, so the same puzzle thats there with the Higgs. Why is the Higgs so light? Its also there with dark energy. Why is the cosmological acceleration of the universe so small compared to what we, we think it is. So its a slightly odd situation to be in. I mean, we have this theory. Its completely amazing. But its also clear there are things we really dont understand.

Strogatz (40:26): I just want to thank you, David Tong, for this really wide-ranging and fascinating conversation. Thanks a lot for joining me today.

Tong (40:33): My pleasure. Thanks very much.

Announcer (40:39): If you like The Joy of Why, check out the Quanta Magazine Science Podcast, hosted by me, Susan Valot, one of the producers of this show. Also tell your friends about this podcast and give us a like or follow where you listen. It helps people find The Joy of Why podcast.

Steve Strogatz (41:03): The Joy of Why is a podcast from Quanta Magazine, an editorially independent publication supported by the Simons Foundation. Funding decisions by the Simons Foundation have no influence on the selection of topics, guests, or other editorial decisions in this podcast or in Quanta Magazine. The Joy of Why is produced by Susan Valot and Polly Stryker. Our editors are John Rennie and Thomas Lin, with support by Matt Carlstrom, Annie Melchor and Leila Sloman. Our theme music was composed by Richie Johnson. Our logo is by Jackie King, and artwork for the episodes is by Michael Driver and Samuel Velasco. Im your host, Steve Strogatz. If you have any questions or comments for us, please email us at quanta@simonsfoundation.org. Thanks for listening.

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What Is Quantum Field Theory and Why Is It Incomplete? - Quanta Magazine

Many people have had paranormal experiences that they can't explain, while others are quick to dismiss that ghosts exist.

Ghosts are the visual essence of those who have died. You may not think about it, or you may not have ever told anyone because you're afraid of how they will respond.

While many seek professional help after seeing ghosts, most arent that fortunate, often telling their doctors or therapists, who mistake psychic vision for psychosis; the wrongful diagnosis, medication, and hospitalizations do more harm than they realize.

In many cultures all around the world and throughout history, there has been a long-standing belief that a person's spirit can survive after death, transcending beyond the physical world.

Ghosts have been part of religion, folklore, and even the arts. And people who have had near-death experiences have said there is life after death, along with highly sensitive individuals whose empathic abilities allow them to see beyond the physical realm.

Despite there being some instances where alleged apparitions have appeared in film or photographs, the truth is that ghosts may exist, and they may not exist we truly don't know.

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With ghosts such a prevalent part of entertainment (shows like "Ghost Hunters" and movies like "Paranormal Activity"), it's no surprise that 46% of Americans believe in ghosts. But the reason may not have anything to do with the media we consume.

The main reason people believe in ghosts is because of having an experience with the paranormal. Perhaps they are sensitive to otherworldly presences, they grew up in a home that was said to be haunted, or have captured spirits on film.

The good news is if you're one of the people who can see ghosts or sense this type of energy, we're scientifically beginning to understand how seeing a ghost may be possible.

You see, whats happening is a paradigm shift in psychology. The same kind of shift that happened in physics after the discoveries in quantum physics. Its just that its taken psychology over a century to catch up, and really, the shift is only now beginning.

Well, the mainstream field of psychology has been based on the old (19th century and before) materialistic view of the world, that this material plane of reality is the only reality. This is what is referred to as old Newtonian physics.

And this is what most of us learned in school: that there are smaller and smaller physical building blocks out of which we are made. In fact, particle physicists specialize in hunting down and then finding smaller and smaller particles.

On the other hand, the new psychology is based on a more quantum understanding of the world, the view ushered in when quantum physics was born in the early 1920s. This is the science that is starting to help us understand that there is much more to our world that we cant see (estimated between 93-99.9999 percent of reality), than what we can see.

For a clue as to how this is possible, consider that the visible part of the electromagnetic light spectrum is just a tiny sliver of the entire range of frequencies of light.

The visible portion is what we see in a rainbow, the red to violet light. Slower or faster vibration than that, and we cant see it. (It's kind of like how dogs hear sounds we dont hear, or hear sounds that too are out of our range).

What were those discoveries that led to more quantum physics? And how is this related to ghosts?

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RELATED: 6 Signs A Spirit Is Trying To Warn You

Kind of like when we have an adult and a young kid nature inside of us. Sometimes we behave more like the child, and sometimes we behave more like the adult.

It's the same with light. Sometimes it behaves more like we would expect a wave of light to move, but at other times, it looks more as if it were a particle or photon of light.

Apparently, when we decide it moves like a wave, it does. When we decide its a particle, it is. This was called the observer effect, and launched a wave of new science, which began to take into account the role that our human consciousness plays in the creation of a physical reality.

The implications of this are huge, including how important each of us is in creating this world.

Even more mind-blowing is the finding that the observer effect works not only forward, but also backward in time. (And that both time and space are not absolute laws of nature that we once believed.)

This wave aspect is really about moving energy, and the patterns created when energy moves (look to the sky when a storm is forming, especially a tornado or hurricane, to get a deeper hint of this).

As it turns out, these wave patterns serve as a design template for the construction of the particle.

If you want to see a really great example, watch the video of cymatics, the work of Dr. Hans Jenny and his followers, and see how sound waves make patterns in various materials.

Now, realize that you have a wave-particle dual self, and that your wave self, the part of you that evidently exists first, is used as a template to make your body self. Starting to see what ghosts might really be?

Its possible that ghosts are the wave essence of a human being. The body may be gone, but the energy waves live on.

And this wave pattern may be what some of you can see, who have clairvoyant sight. Furthermore, those who experience clairvoyance may simply be more gifted in detecting a broader bandwidth of energy frequencies than the rest of us.

Physicist William A. Tiller might call you higher consciousness because you have a greater channel capacity than most of us kind of like the latest and greatest cable television ever.

So, if you see ghosts, know you're not alone and that there are many more transpersonal psychotherapists out there who believe you. We know you're likely not "crazy," just quantum both in vision and in reality.

RELATED: How Cats Protect You And Your Home From Ghosts And Negative Spirits, Based On Their Fur Color

Valerie Varan, MS, LPC, NCC is a holistic counselor and coach, and the author of 'Living in a Quantum Reality: Using Quantum Physics and Psychology to Embrace Your Higher Consciousness.' Follow her on Facebook or learn more about her holistic psychotherapy practice on her website.

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What Science & Quantum Physics Say About Whether Or Not Ghosts Are Real - YourTango

Were learning theres a lot more to learn about nothing than we thought, said Isabel Garcia Garcia, a particle physicist at the Kavli Institute for Theoretical Physicsin California. How much more are we missing?

So far, such studies have led to a dramatic conclusion: Our universe may sit on a platform of shoddy construction, a metastable vacuum that is doomed in the distant future to transform into another sort of nothing, destroying everything in the process.

Nothing started to seem like something in the 20th century, as physicists came to view reality as a collection of fields: objects that fill space with a value at each point (the electric field, for instance, tells you how much force an electron will feel in different places). In classical physics, a fields value can be zero everywhere so that it has no influence and contains no energy. Classically, the vacuum is boring, said Daniel Harlow, a theoretical physicist at the Massachusetts Institute of Technology. Nothing is happening.

But physicists learned that the universes fields are quantum, not classical, which means they are inherently uncertain. Youll never catch a quantum field with exactly zero energy. Harlow likens a quantum field to an array of pendulums one at each point in space whose angles represent the fields values. Each pendulum hangs nearly straight down but jitters back and forth.

Left alone, a quantum field will stay in its minimum-energy configuration, known as its true vacuum or ground state. (Elementary particles are ripples in these fields.) When we talk about the vacuum of a system, we have in mind in some loose way the preferred state of the system, said Garcia Garcia.

Most of the quantum fields that fill our universe have one, and only one, preferred state, in which theyll remain for eternity. Most, but not all.

In the 1970s, physicists came to appreciate the significance of a different class of quantum fields whose values prefer not to be zero, even on average. Such a scalar field is like a collection of pendulums all hovering at, say, a 10-degree angle. This configuration can be the ground state: The pendulums prefer that angle and are stable.

In 2012, experimentalists at the Large Hadron Collider proved that a scalar field known as the Higgs field permeates the universe. At first, in the hot, early universe, its pendulums pointed down. But as the cosmos cooled, the Higgs field changed state, much as water can freeze into ice, and its pendulums all rose to the same angle. (This nonzero Higgs value is what gives many elementary particles the property known as mass.)

With scalar fields around, the stability of the vacuum is not necessarily absolute. A fields pendulums might have multiple semi-stable angles and a proclivity for switching from one configuration to another. Theorists arent certain whether the Higgs field, for instance, has found its absolute favorite configuration the true vacuum. Some have argued that the fields current state, despite having persisted for 13.8 billion years, is only temporarily stable, or metastable.

If so, the good times wont last forever. In the 1980s, the physicists Sidney Coleman and Frank De Luccia described how a false vacuum of a scalar field could decay. At any moment, if enough pendulums in some location jitter their way into a more favorable angle, theyll drag their neighbors to meet them, and a bubble of true vacuum will fly outward at nearly light speed. It will rewrite physics as it goes, busting up the atoms and molecules in its path. (Dont panic. Even if our vacuum is only metastable, given its staying power so far, it will probably last for billions of years more.)

In the potential mutability of the Higgs field, physicists identified the first of a practically infinite number of ways that nothingness could kill us all.

As physicists have attempted to fit natures confirmed laws into a larger set (filling in giant gaps in our understanding in the process), they have cooked up candidate theories of nature with additional fields and other ingredients.

When fields pile up, they interact, influencing each others pendulums and establishing new mutual configurations in which they like to get stuck. Physicists visualize these vacuums as valleys in a rolling energy landscape. Different pendulum angles correspond to different amounts of energy, or altitudes in the energy landscape, and a field seeks to lower its energy just as a stone seeks to roll downhill. The deepest valley is the ground state, but the stone could come to rest for a time, anyway in a higher valley.

A couple of decades ago, the landscape exploded in scale. The physicists Joseph Polchinski and Raphael Bousso were studying certain aspects of string theory, the leading mathematical framework for describing gravitys quantum side. String theory works only if the universe has some 10 dimensions, with the extra ones curled up into shapes too tiny to detect. Polchinski and Bousso calculated in 2000 that such extra dimensions could fold up in a tremendous number of ways. Each way of folding would form a distinct vacuum with its own physical laws.

The discovery that string theory allows nearly countless vacuums jibed with another discovery from nearly two decades earlier.

Cosmologists in the early 1980s developed a hypothesis known as cosmic inflation that has become the leading theory of the universes birth. The theory holds that the universe began with a quick burst of exponential expansion, which handily explains the universes smoothness and hugeness. But inflations successes come at a price.

The researchers found that once cosmic inflation started, it would continue. Most of the vacuum would violently explode outward forever. Only finite regions of space would stop inflating, becoming bubbles of relative stability separated from each other by inflating space in between. Inflationary cosmologists believe we call one of these bubbles home.

To some, the notion that we live in a multiverse an endless landscape of vacuum bubbles is disturbing. It makes the nature of any one vacuum (such as ours) seem random and unpredictable, curbing our ability to understand our universe. Polchinski, who died in 2018, told the physicist and author Sabine Hossenfelder that discovering string theorys landscape of vacuums initially made him so miserable it led him to seek therapy. If string theory predicts every imaginable variety of nothing, has it predicted anything?

To others, the plethora of vacuums is not a problem; in fact, its a virtue, said Andrei Linde, a prominent cosmologist at Stanford University and one of the developers of cosmic inflation. Thats because the multiverse potentially solves a great mystery: the ultra-low energy of our particular vacuum.

When theorists navely estimate the collective jittering of all the universes quantum fields, the energy is huge enough to rapidly accelerate the expansion of space and, in short order, rip the cosmos apart. But the observed acceleration of space is extremely mild in comparison, suggesting that much of the collective jittering cancels out and our vacuum has an extraordinarily low positive value for its energy.

In a solitary universe, the tiny energy of the one and only vacuum looks like a profound puzzle. But in a multiverse, its just dumb luck. If different bubbles of space have different energies and expand at different rates, galaxies and planets will form only in the most lethargic bubbles. Our calm vacuum, then, is no more mysterious than the Goldilocks orbit of our planet: We find ourselves here because most everywhere else is inhospitable to life.

Love it or hate it, the multiverse hypothesis as currently understood has a problem. Despite string theorys seemingly infinite menu of vacuums, so far no one has found a specific folding of tiny extra dimensions that corresponds to a vacuum like ours, with its barely positive energy. String theory seems to yield negative-energy vacuums much more easily.

Perhaps string theory is untrue, or the flaw could lie with researchers immature understanding of it. Physicists may not have hit on the right way to handle positive vacuum energy within string theory. Thats perfectly possible, said Nathan Seiberg, a physicist at the Institute for Advanced Study in Princeton, New Jersey. This is a hot topic.

Or our vacuum could just be inherently sketchy. The prevailing view is that [positively energized] space is not stable, Seiberg said. It could decay to something else, so that could be one of the reasons why it is so hard to understand the physics of it.

These researchers suspect that our vacuum is not one of realitys preferred states, and that it will someday jitter itself into a deeper, more stable valley. In doing so, our vacuum could lose the field that generates electrons or pick up a new palette of particles. The tightly folded dimensions could come unfurled. Or the vacuum could even give up on existence entirely.

Thats another one of the options, Harlow said. A true nothing.

The physicist Edward Witten first discovered the bubble of nothing in 1982. While studying a vacuum with one extra dimension curled up into a tiny circle at each point, he found that quantum jitters inevitably jiggled the extra dimension, sometimes shrinking the circle to a point. As the dimension vanished into nothingness, Witten found, it took everything else with it. The instability would spawn a rapidly expanding bubble with no interior, its mirrorlike surface marking the end of space-time itself.

This instability of tiny dimensions has long plagued string theory, and various ingredients have been devised to stiffen them. In December, Garcia Garcia, together with Draper and Benjamin Lillard of Illinois, calculated the lifetime of a vacuum with a single extra curled-up dimension. They considered various stabilizing bells and whistles, but they found that most mechanisms failed to stop the bubbles. Their conclusions aligned with Wittens: When the size of the extra dimension fell below a certain threshold, the vacuum collapsed at once. A similar calculation one extended to more sophisticated models could rule out vacuums in string theory with dimensions below that size.

With a large enough hidden dimension, however, the vacuum could survive for many billions of years. This means that theories producing bubbles of nothing could plausibly match our universe. If so, Aristotle may have been more right than he knew. Nature may not be a big fan of the vacuum. In the extremely long run, it may prefer nothing at all.

Correction: August 10, 2022

Otto von Guerickes vacuum-filled copper sphere was the size of a watermelon, rather than the size of a grapefruit as initially stated.

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How the Physics of Nothing Underlies Everything - Quanta Magazine

Car co-invented the approach to using underlying quantum mechanical laws to predict the physical movements of atoms and molecules. Quantum mechanical laws dictate how atoms bind to each other to form molecules, and how molecules join with each other to form everyday objects.

Car and Michele Parrinello, a physicist now at the Istituto Italiano di Tecnologia in Italy, published their approach, known as ab initio (Latin for from the beginning) molecular dynamics, in a groundbreaking paper in 1985.

But quantum mechanical calculations are complex and take tremendous amounts of computing power. In the 1980s, computers could simulate just a hundred atoms over spans of a few trillionths of a second. Subsequent advances in computing and the advent of modern supercomputers boosted the number of atoms and timespan of the simulation, but the result fell far short of the number of atoms needed to observe complex processes such as ice nucleation.

AI provided an attractive potential solution. Researchers train a neural network, named for its similarities to the workings of the human brain, to recognize a comparatively small number of selected quantum calculations. Once trained, the neural network can calculate the forces between atoms that it has never seen before with quantum mechanical accuracy. This machine learning approach is already in use in everyday applications such as voice recognition and self-driving automobiles.

In the case of AI applied to molecular modeling, a major contribution came in 2018 when Princeton graduate student Linfeng Zhang, working with Car and Princeton professor of mathematics Weinan E, found a way to apply deep neural networks to modeling quantum-mechanical interatomic forces. Zhang, who earned his Ph.D. in 2020 and is now a research scientist at the Beijing Institute of Big Data Research, called the approach deep potential molecular dynamics.

In the current paper, Car and postdoctoral researcher Pablo Piaggi along with colleagues applied these techniques to the challenge of simulating ice nucleation. Using deep potential molecular dynamics, they were able to run simulations of up to 300,000 atoms using significantly less computing power, for much longer timespans than were previously possible. They carried out the simulations on Summit, one of the worlds fastest supercomputers, located at Oak Ridge National Laboratory.

This work provides one of the best studies of ice nucleation, said Pablo Debenedetti, Princetons dean for research and the Class of 1950 Professor of Engineering and Applied Science, and a co-author of the new study.

Ice nucleation is one of the major unknown quantities in weather prediction models, Debenedetti said. This is a quite significant step forward because we see very good agreement with experiments. Weve been able to simulate very large systems, which was previously unthinkable for quantum calculations.

Currently, climate models obtain estimates of how fast ice nucleates primarily from observations made in laboratory experiments, but these correlations are descriptive, not predictive, and are valid over a limited range of experimental conditions. In contrast, molecular simulations of the type done in this study can produce simulations that are predictive of future situations, and can estimate ice formation under extreme conditions of temperature and pressure, such as on other planets.

The deep potential methodology used in our study will help realize the promise of ab initio molecular dynamics to produce valuable predictions of complex phenomena, such as chemical reactions and the design of new materials, said Athanassios Panagiotopoulos, the Susan Dod Brown Professor of Chemical and Biological Engineering and a co-author of the study.

The fact that we are studying very complex phenomena from the fundamental laws of nature, to me that is very exciting, said Piaggi, the studys first author and a postdoctoral research associate in chemistry at Princeton. Piaggi earned his Ph.D. working with Parrinello on the development of new techniques to study rare events, such as nucleation, using computer simulation. Rare events take place over timescales that are longer than the simulation times that can be afforded, even with the help of AI, and specialized techniques are needed to accelerate them.

Jack Weis, a graduate student in chemical and biological engineering, helped increase the likelihood of observing nucleation by seeding tiny ice crystals into the simulation. The goal of seeding is to increase the likelihood that water will form ice crystals during the simulation, allowing us to measure the nucleation rate, said Weis, who is advised by Debenedetti and Panagiotopoulos.

Water molecules consist of two hydrogen atoms and an oxygen atom. The electrons around each atom determine how atoms can bond with each other to form molecules.

We start with the equation that describes how electrons behave, Piaggi said. Electrons determine how atoms interact, how they form chemical bonds, and virtually the whole of chemistry.

The atoms can exist in literally millions of different arrangements, said Car, who is director of the Chemistry in Solution and at Interfaces center, funded by the U.S. Department of Energy Office of Science and including regional universities.

The magic is that because of some physical principles, the machine is able to extrapolate what happens in a relatively small number of configurations of a small collection of atoms to the countless arrangements of a much bigger system, Car said.

Although AI approaches have been available for some years, researchers have been cautious about applying them to calculations of physical systems, Piaggi said. When machine learning algorithms started to become popular, a big part of the scientific community was skeptical, because these algorithms are a black box. Machine learning algorithms dont know anything about the physics, so why would we use them?

In the last couple of years, however, there has been a significant change in this attitude, Piaggi said, not only because the algorithms work but also because researchers are using their knowledge of physics to inform the machine learning models.

For Car, it is satisfying to see the work started three decades ago come to fruition. The development came via something that was developed in a different field, that of data science and applied mathematics, Car said. Having this kind of cross interaction between different fields is very important.

This work was supported by the U.S. Department of Energy (grant DE-731 SC0019394) and used resources of the Oak Ridge Leadership Computing Facility (grant DE-AC05-00OR22725) at the Oak Ridge National Laboratory. Simulations were substantially performed using the Princeton Research Computing resources at Princeton University. Pablo Piaggi was supported by an Early Postdoc.Mobility fellowship from the Swiss National Science Foundation.

The study, Homogeneous ice nucleation in an ab initio machine learning model of water, by Pablo M. Piaggi, Jack Weis, Athanassios Z. Panagiotopoulos, Pablo G. Debenedetti, and Roberto Car, was published in the journal Proceedings of the National Academy of Sciences the week of August 8, 2022. DOI: /10.1073/pnas.2207294119.

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Researchers Simulate Ice Formation by Combining AI and Quantum Mechanics - HPCwire

D-Wave completed a planned merger on Monday with DPCM Capital (the latter of which was already listed on the New York Stock Exchange), making the Canada-basedfirm the third quantum player to go public via a SPACthat is, a special purpose acquisition companywithin the last year. (The other companies? Rigetti and IonQ.)

Its an interesting trend, but perhaps not a surprising one: According to D-Wave CEO Alan Baratz, the until-recently-obscure financial quirk offers his companyone thats in a still-budding sectorfaster access to capital.

In some sense SPACs are ideal for a company that has huge potential but is going to take some time to mature,he tells Fast Company. With a SPAC, youre able to tap into the funding sources in the public markets to accelerate your growth and do it based on the future potential.

A traditional IPO, on the other hand, is all about today, he adds.

SPACs can also save companies money (though this point is subject to some debate). I dont think all SPACs should be discounted, says Patrick Moorhead of Moor Insights & Strategy, a consulting firm. Its a much less expensive way to go public and takes less time and effort.

So far, D-Waves post-SPAC stock is holding its own. It opened at $9.98 Monday and closed at $11.86 on Thursday. But Rigetti and IonQ havent fared as well. Rigetti has seen its shares drop in value by roughly half since its listing on the NASDAQ in March. IonQs shares have lost about 40% of their value since its listing in October 2021.

In the young field of quantum computing, D-Wave has emerged as a major character. Back in 2011, the company became the first to actually sell a quantum computer; it now counts NASA, Google, and Lockheed Martin as customers.

Building and operating a quantum computer is an extraordinary feat of science and engineering. Instead of the bits used in traditional computers (which can be set to zero or one), quantum computers use subatomic particles called qubits, which can represent many values between zero and one, as well as zero and one at the same time (a superposition). Qubits can also entangle to represent values in extremely complex problems. In order to take advantage of these properties, the computer has to control the state of the qubits, whose erratic behavior is governed by quantum physics, not regular physics. This is very hard, and usually involves supercooling the qubits to slow their constant spin, then using lasers or electricity to control their state.

D-Wave was able to get to market with a quantum computer because it adopted a unique approach to working with the qubitsone that asks far less of them. What its looking for is the minimum energy level within a qubit, and by finding the minimum energy level, then theyre able to find the most optimized solution to a problem, says Heather West, research manager at research firm IDC. And thats why D-Wave is able to say they have 5,000 to 7,000 qubits in their system versus an IBM, which is still down around 127.

Even though that approach, called quantum annealing, doesnt try to exert a lot of control over the states of the qubits, its still very useful for solving optimization problemsthat is, problems where the goal is to find the best solution among a huge number of possibles. An optimization problem might be finding the optimal routes and cargos for a large fleet of delivery trucks, or finding the optimal number of employees to schedule on a given day. Its a common type of business puzzle, and annealers are especially good at solving them.

Some of these industries really gravitated toward D-Wave because of those optimization problems, and being able to pull in all sorts of data to find these optimized solutions and solving problems faster was really appealing, West says.

That application is a good example of the way companies are using quantum services like D-Wave today. Theyre looking for problem types where classical computers struggle and quantum computers excel.

They [D-Wave] are really more of an accelerator, says Ashish Nadkarni, group VP and general manager at IDC. We are not at the point where you can completely run all kinds of jobs on a quantum computer.

But D-Waves annealer may eventually be seen as a forerunner to a more robust kind of quantum computing, called gate model, in which the quantum computer takes full advantage of the quantum properties of the qubitstheir many possible states, their capacity for superposition, and the compute power enabled by multiple qubits entangling with each other.

Controlling and leveraging these properties opens the possibility of solving problems that are far beyond the reach of classical supercomputers (and annealers). These are large probabilistic problems where the qubits are asked to model huge and complex data sets. It could be modeling all the receptors in the brain to explore how theyll react to a drug, or a huge array of stock market conditions to predict their effect on the price of a certain commodity.

Realizing that much of the upside and excitement around quantum computing is coming from the possibility to solve such problems, D-Wave announced last year that it had begun building gate-model quantum computers more like the ones built by Google, IBM, and IonQ. D-Wave will need years to develop its gate-model quantum, but Baratz believes offering both annealers and gate-model quantum computing will eventually put his company at an advantage.

By doing both and being the only company thats doing both, were the only company in the world that will be able to address the full market for quantum, and the full set of use cases, he says. D-Waves customers typically tap into these computing services via a dedicated cloud service.

Because quantum is considered a nascent technology, many potential customers (such as companies in the financial services and pharmaceutical industries) are experimenting with running certain types of algorithms on quantum systems to look for some advantage over classical computing. But theyre not necessarily paying customers.

Baratz says that its the gate-model quantum services that are nascent technology, not D-Waves annealers, which he says are ready to deliver real value today. He believes the gate-model quantum computers are still as many as seven years away from being able to run general business applications in a way that beats classical computers.

Baratz believes that D-Wave is now challenged to make sure customers differentiate between gate-model computingwhich he says could be as many as seven years away from running real business applicationsand D-Waves quantum annealing service, which is mature and ready to deliver value today. While his gate-model competitors are out telling customers its okay to dip their toes into the water and experiment, D-Wave must counter that narrative in the marketplace with the message that customers can be doing real optimization work using quantum annealing now.

We truly are commercial, so when our competitors talk about revenue, they talk about government research grants as revenue, and they talk about national labs and academic institutions as customers, Baratz says. When we talk about our customers, we talk about our recently announced deal with MasterCard, or Deloitte or Johnson & Johnson or Volkswagen.

Baratz says over 65% of D-Waves quantum cloud revenue last year came from more than 50 commercial customers, which include over two dozen members of the Forbes Global 2000.

Baratz says D-Wave is now entering a phase in which it can leverage its annealers to start customer relationships.

We do have a significant head start, but we think now is the time to really make the investment to grow that loyal customer base and get the market share, Baratz says.And then, as we bring new generations of annealing to market, its just an upsell to more complex applications as we bring gate [model] to market.

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D-Wave is the third quantum startup to SPAC in less than a year - Fast Company

Worried about your aging brain? One solution might be on a shelf in the refrigerator aisle of your grocery store, according to new research conducted by scientists at the University of Kansas Medical Center.

The KU Medical Center research team found that older adults who drink three cups of dairy milk a day can increase their brains level of glutathione (GSH), a powerful antioxidant that helps protect the brain from some of the damage that accompanies aging and aging-related diseases. (The typical American adult over age 60 drinks less than two cups of milk per day, according to data from the Centers for Disease Control and Prevention.)

Just like an old car that rusts, the human brain becomes corroded over time by free radicals and other oxidants that are released as the brain converts nutrients into energy. This oxidative stress, as its called, is believed to be a major mechanism of brain aging as well as many neurodegenerative diseases including Alzheimers and Parkinsons. GSH helps stave off oxidative stress and the damage it causes. But as people age, brain levels of GSH tend to fall.

It's exciting that something as simple as drinking milk can increase GSH because its not a drug, its just a simple food, said Debra Sullivan, Ph.D., RD, professor and chair of the Department of Dietetics and Nutrition in the School of Health Professions at KU Medical Center and an author on the study, which was published August 15 in Frontiers in Nutrition. And the three cups a day is actually what is recommended by the U.S. Dietary Guidelines.

The study builds on work that Sullivan began over a decade ago with In-Young Choi, Ph.D., lead author on the study and director of the Metabolic Imaging Unit and the Magnetic Resonance Science Program at the Hoglund Biomedical Imaging Center at KU Medical Center. Choi, who focuses on brain aging and neurodegeneration, had collaborated with Phil Lee, Ph.D., a professor of the Department of Radiology, to develop a novel magnetic resonance imaging technique that can measure the level of antioxidants in the brain. These unique scans use special imaging techniques based on a multiple quantum physics concept and can selectively detect GSH in different parts of the brain simultaneously, Choi said.

Sullivan approached Choi about collaborating and using her brain antioxidant scanning technique to measure how what people eat affects their brain. When they completed their first exploratory study, they were surprised by the results.

I was thinking fruits and vegetables would be highly correlated with antioxidants in the brain, remembered Choi. But instead it was dairy, and among the dairy foods, it was milk. That was really surprising.

The researchers then applied for and were awarded a grant from the National Dairy Council, which along with a National Institutes of Health (NIH) grant that funds the Hoglund Biomedical Imaging Center, supports their work. These funders have no input on the study design, data, the interpretation of the data or the writing the manuscript, Sullivan said.

In 2015, Choi and Sullivan and their team published an observational study in the American Journal of Clinical Nutrition that again found that milk was highly correlated with concentrations of GSH in the brain of older adults. The next step, the current study, was designed to see what would happen to someones brain if that person increased their milk consumption.

In this study, 73 adults aged between the ages of 60 and 89 who typically consumed less than 1.5 servings of dairy per day were randomly assigned into a control group, which did not alter its usual milk intake, and into an intervention group, which increased their milk intake to three cups per day for three months. The study provided the participants in the intervention group with low-fat 1% milk from regional Kansas City area grocery stores weekly. For both groups, brain antioxidant imaging scans were conducted at baseline and after three months.

While there was no change in the levels of GSH in the brains of the participants in the control group, the group that drank three cups of dairy milk a day saw their brain GSH levels increase by an average of nearly 5% overall and by more than 7% in the parietal region of the brain.

Choi noted that earlier findings have shown that GSH levels are lower in older adults about 10%. So, by drinking milk, it looks like you can catch up some, she said.

What remains to be discovered is the specific mechanisms by which milk increases levels of GSH in the brain. The researchers know this much: The GSH molecule is made of three amino acidsglycine, glutamate, and cysteineand milk is a source of all three. Compared with other foods, the whey protein in milk has particularly high levels of cysteine, which is especially important for the body to make more GSH. Milk is also rich in riboflavin and calcium, which are required for GSH maintenance.

More research is needed to determine which of these factors are behind the increase in brain GSH levels. The researchers also plan to conduct a larger study as well as studies including cognitive tests to measure if milk is leading to measurable changes in brain function. They also want to determine if there is an optimal dose of milk and if the amount of milk fat matters.

In the meantime, Sullivan sees no reason to wait to make sure youre getting your three cups of milk each day. Its important for your brain health, your bone health, your muscle health, all of those things, she said. Thats the takeaway.

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Drinking more dairy milk may improve brain health in older adults, KU Medical Center researchers find - University of Kansas Medical Center

About Centre for Quantum Technologies (CQT)

The Centre for Quantum Technologies (CQT) is a research centre of excellence in Singapore. It brings together physicists, computer scientists and engineers to do basic research on quantum physics and to build devices based on quantum phenomena. Experts in this new discipline of quantum technologies are applying their discoveries in computing, communications, and sensing. CQT is hosted by the National University of Singapore and also has staff at Nanyang Technological University. With some 180 researchers and students, it offers a friendly and international work environment. Learn more about CQT at http://www.quantumlah.org

Job Description

The key job purpose is to extend our previous studies of artificial gauge field in SU(2) to SU(3) symmetry. We are using an ultracold gas of Strontium atoms and simple generalization to our tripod system. SU(3) symmetry appears in the Yang-Mills theory for high energy physics and more recently in specific problems in condensed-matter physics where three-fold band structure are engineered (Weyl semimetal, spintronics). One important aspect of SU(3) with respect to SU(2) is its higher dimensionality which allow for richer topological properties. For example, SU(3) transformations naturally break the time invariance symmetry leading to singularities of the Berry curvature and related magnetic monopoles.

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Location: [[NTU]]Organization: [[NUS]]Department: [[David Wilkowski's group]]Job requisition ID: [[16651]]

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Research Fellow (David Wilkowski 's Group), Centre for Quantum Technologies job with NATIONAL UNIVERSITY OF SINGAPORE | 304528 - Times Higher...