Three physicists working independently, from France, the U.S., and Austria, have nabbed this year’s Nobel Prize in Physics for work on quantum entanglement. (Note the international character of the awardees.) All three share equally in the prize, a total of ten million Swedish kroner (about $1.3 million US. It’s not a munificent amount, but the value to one’s career an esteem in inestimable. The winners will henceforth always be designated as “Nobel Laureate [name here].”
What did they win for? Well, you can read about it at either the Nobel press-release site (below) or the NYT article below that; click on either to read. Trigger warning: quantum physics! The award has to do with quantum entanglement, a phenomenon that I can barely understand but that Einstein dismissed as “spooky action at a distance.” Beyond that, even the physicists who wrote me about this don’t fully understand the accomplishment that was honored, for which entanglement is just the starting point.
From the NYT:
A summary from the NYT with a good explanation of entanglement (I’ve put it in bold below):
The Nobel Prize in Physics was awarded to Alain Aspect, John F. Clauser and Anton Zeilinger on Tuesday for work that has “laid the foundation for a new era of quantum technology,” the Nobel Committee for Physics said.
The scientists have each conducted “groundbreaking experiments using entangled quantum states, where two particles behave like a single unit even when they are separated,” the committee said in a briefing. Their results, it said, cleared the way for “new technology based upon quantum information.”
The laureates’ research builds on the work of John Stewart Bell, a physicist who strove in the 1960s to understand whether particles, having flown too far apart for there to be normal communication between them, can still function in concert, also known as quantum entanglement.
According to quantum mechanics, particles can exist simultaneously in two or more places. They do not take on formal properties until they are measured or observed in some way. By taking measurements of one particle, like its position or “spin,” a change is observed in its partner, no matter how far away it has traveled from its pair.
Working independently, the three laureates did experiments that helped clarify a fundamental claim about quantum entanglement, which concerns the behavior of tiny particles, like electrons, that interacted in the past and then moved apart.
And the accomplishments of the three, also from the NYT:
Dr. Clauser, an American, was the first in 1972. Using duct tape and spare parts at Lawrence Berkeley National Laboratory in Berkeley, Calif., he endeavored to measure quantum entanglement by firing thousands of photons in opposite directions to investigate a property known as polarization. When he measured the polarizations of photon pairs, they showed a correlation, proving that a principle called Bell’s inequality had been violated and that the photon pairs were entangled, or acting in concert.
Clauser looks as if he won it for demonstrating the phenomenon of entanglement fifty years ago, but, according to Wikipedia, entanglement of photons was experimentally demonstrated in the year I was born.
The first experiment that verified Einstein’s spooky action at a distance or entanglement was successfully corroborated in a lab by Chien-Shiung Wu and a colleague named I. Shaknov in 1949, and was published on new year’s day in 1950. The result specifically proved the quantum correlations of a pair of photons.
Wu won the Nobel Prize for that, but what was entangled was “parity,” not “polarization” (several aspect of photons’ properties are entangled). But Wu and her colleague’s experiments seem to have demonstrated the violation of Bell’s inequality in 1949.
More from the NYT:
The research was taken up 10 years later by Dr. Aspect, a French scientist, and his team at the University of Paris. And in 1998, Dr. Zeilinger, an Austrian physicist, led another experiment that considered entanglement among three or more particles.
Eva Olsson, a member of the Nobel Committee for Physics, noted that quantum information science had broad implications in areas like secure information transfer and quantum computing.
Quantum information science is a “vibrant and rapidly developing field,” she said. “Its predictions have opened doors to another world, and it has also shaken the very foundation of how we interpret measurements.
The Nobel committee said the three scientists were being honored for their experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science.
“Being able to manipulate and manage quantum states and all their layers of properties gives us access to tools with unexpected potential,” the committee said in a statement on Twitter.
Two physics mavens who wrote me about this admitted they didn’t fully grasp what the Laureates had shown.
One said this:
Hell. I don’t even understand the title of the physics area of this year’s award. My days are over!
And the other said this:
Whoooosh … right over my head ! I have absolutely no idea what they are talking about!
Readers are welcome to clarify. But it’s quantum mechanics, Jake, and if you think you understand its physical interpretation, as Feynman said, you don’t. That’s what’s so fascinating about the area. The math seems to absolutely predict what you see, but to translate the mathematical results into language that corresponds to our everyday experience is nearly impossible.
Here’s the one-hour live announcement:
And our contest, based on the failure of readers to guess who would win all the Prizes in a given year. I’m thus restricting the contest to one prize only. To wit:
The Nobel Prize in Literature will be awarded early Thursday morning (US time). Who will win it?
The first person who guesses the correct answer and puts it below in a post gets an autographed copy of either WEIT or Faith versus Fact, personalized to their liking and with a cat or other animal of their choosing drawn in it by me, PCC(E).
Put your choices below. The contest closes at 8 pm Eastern US time on Wednesday (tomorrow).
Salman Rushdie is very deserving.
The Nobel Prize in Literature will be awarded to:
Herschel Walker, running for senator from Georgia.
He’s nothing if not a fabulist.
Perfect description 🙂
I love the commentary!
So far a delightfully surprising Nobel Prize season!
… is it really for “technology”, NYT? It is surely – yes, surely – for _discovery_ … if only someone can … UNENTANGLE the riddle….
Also looks like Clauser was -_not_ in academia at the time of award. Not sure if it’s s company he was in.
Do DeLillo
As one of the mavens mentioned above, I do recommend Hans von Baeyer’s 2016 book, “QBism – the future of quantum physics” (Harvard) in which he discusses a Bayesian probability application to quantum mechanics. The author describes himself as a “quantum mechanic in retirement”. I knew him as an one of the best explainers of physics on the physics faculty at the College of William an Mary. I read primarily about this application of Rev Bayes’ theory, which I found extremely helpful in a world in which high school probability continues to be taught in a (and our cultural assumptions continue to be in a ) “frequentist” framework. I intend to re-read the book now for the physics along with the mathematics.
Cormac McCarthy
A few years ago I read How the hippies saved physics which is a very good account of the strange environment that promoted research on this esoteric field in the early days. I don’t remember many details but Clauser is one of the central figures in the story. The book is very entertaining and discusses QM and entanglement in some detail (without math). Worth reading for those interested in both the science and the cultural sides.
Apparently I screwed up the format with the book link. Sorry.
Sarcasm on:
Oh, I see the three laureates are all white males. If they turn up to be cis too, then they should cancel the awards altogether. Not enough diversity 😉
Sarcasm pile on: well, check out the portraits on the wall in the room where this morning’s announcement was made at the Academy. I just cannot be rational about wokeness.
A correction: Chien-Shiung Wu never won a Nobel Prize. This is widely seen as a disgraceful oversight by the Nobel committee, since two theorists did win for the non-conservation of parity that Wu demonstrated experimentally. This was a spectacular experiment, requiring then state-of-the-art technique in both the measure of electron spin and in the use of very low temperatures.
My hope (and guess): Salman Rushdie
Edna O’Brien
John Banville
Since Don DeLillo and Cormac McCarthy are already taken, I’ma go with Thomas Pynchon.
Though that’s probably just my Yank chauvinism showing through.
Margaret Atwood
Seconded.
Although, since Dylan won it a few years ago, I feel justified in nominating Joni Mitchell as an alternate.
As the prizes in literature tend to be slightly politically motivated, I agree that Rushdie is a good bet. But to avoid boredom, I suggest the laureate will be a Ukrainian author this year, and I put my bet on Serhii Zhadan. Although he, like all the post-Soviet “national” Ukrainian authors that I have heard of, is a bit too young.
I first read about the Aspect experiment in the early 80’s in Science et Vie – I didn’t understand anything then.
All the QM textbooks of the last 25 years have dedicated chapters on the Stein-Gerlach experiment and entanglement and I have often wondered why experiments about entanglement are not eligible for a Nobel.
I recommend Michael Raymer – Quantum Physics: What Everyone Needs to Know, and Jim Baggott – Quantum Reality: The Quest for the Real Meaning of Quantum Mechanics – A Game of Theories. I didn’t like, being too storylike, Anton Zeilinger’s book – Dance of the Photons: From Einstein to Quantum Teleportation.
STERN-Gerlach, not Stein 🙂
Entanglement research is an excellent subject for some Nobel prizes.
Murakami
Excellent choice! I always forget about him for some reason. The story of how he became a novelist is about as banal as that of PCC(E)’s becoming an atheist. He was at a baseball game, someone (an American in the Japanese majors, I think) hit a fly ball, and at that moment the thought popped into his head: hey, I think I could write a novel. He went home and started that very night.
The first author that came to mind was Salman Rushdie, and I wasn’t surprised to see a few others list him already. Also, I don’t know if his recent assault will throw some empathy his way, but I thought it might.
DeLillo and McCarthy are always on my list of hopefuls, and they’ve been mentioned as well.
I think Ken’s Pynchon guess is a good one.
As usual, it will probably be someone I don’t know and have never read; and please don’t pick a musician. I love Dylan, but I still consider his nomination a bad joke.
Rushdie deserves it as much as anyone, but I wonder if fear of reprisals from Islamic fundamentalists will eliminate him from the running. I’m going with Banville, but only because McCarthy was taken.
The Nobel lit prize is much misunderstood; it’s not necessarily awarded to the “best” writers so much as those of wide societal or sociological impact. Just take a look at the list of winners, comprised largely of forgotten mediocrities and notable for the absence of Tolstoy, Ibsen, Joyce, Nabokov, Auden, Borges, Greene, etc. In my opinion it’s nearly as unfunny a joke as the Peace Prize (Kissinger? Mother Teresa? Arafat? Obama? Gimme a break!)
I was much amused at Dylan’s win, as I make a short list of predictions every year (which is never, ever right) and it never crossed my mind to include him. When l heard he had won I dismissed it as a joke at first, and I LOVE Bob.
You make good points.
How can it not be Margaret Atwood? (Yes, I know, she’s taken)
It would seem that too big a deal has been made out of quantum entanglement. According to Sabine Hossenfelder in her latest book, “Existential physics”, Einstein used the phrase “spooky action at a distance” to refer to the collapse of the wave function, not to entanglement. I highly recommend the first 3/4 of her book. The rest takes on subjects which are too unlikely in my opinion: Does the universe think; are humans predictable?
I would love to see Pynchon awarded the prize, altho there is a good chance he would either refuse it or send someone else to do so.
Yes, I just finished her book. Actually, I didn’t like most of it that much, as she doesn’t explain things as well as she thinks she does (viz. the “principle of least action”). But some bits are great, and of course I agree with her take on determinism and free will. I agree about the lack of interest in questions like “does the Universe think?”, but her discussion of free will was pretty good from a physics standpoint. (In my view, Sam Harris did a better job, though.) Much as I like Hossenfelder’s videos, I wouldn’t recommend her book.
Michel Houellebecq
Replace Michel Houellebecq with Rebecca Goldstein as my Nobel guess.
It would be cool for Goldstein and Pinker to receive the prize jointly (do the rules allow for that?). I have not read her by the way, just her hubby.
The rules do allow it, though it’s rare in literature. It would be cool. Try Goldstein’s 36 Arguments for the Existence of God, A Work of Fiction or Betraying Spinoza, The Renegade Jew Who Gave Us Modernity.
roger wilco ~ Spinoza rocks!
I just noticed that Sixty Symbols has a new video of related content called “Spooky Action at a Distance (Bell’s Inequality) featuring Prof. Mike Merrifield. I haven’t watched it yet but Brady Haran and co. rarely fail to deliver the goods. I’d link to it here if I wasn’t such a halfwit, technologically speaking.
The last five have been Japanese/English (Kashiguro); Polish (Tokarkzuk); Austrian (Handke); American (Glück); and Zanzibarian/English (Gurnah). Rushdie deserves it, and ought to get it; but the jury might decide that another continent deserves a turn. Any fans of current South American literature out there?
Cuban poet – Reina María Rodríguez
All you need to know about quantum entanglement by Dr Tenpenny.
https://imgur.com/gallery/i4xw1Bl
From the NYT:
“having flown too far apart for there to be normal communication between them”
I wonder what they could possibly mean by the “normal communication” between them? Unless it is photons going back and forth, there is no known means of “normal” communication between such particles. The distance between them is irrelevant, which is kind of the point.
That’s what it means. The particles are space-like separated, that is so far apart that a signal travelling at any speed up to the speed of light cannot can pass between them during the time of the experiment. Thus ruling out any form of Relativity complaint communication.
The only alternatives left to explain entanglement are either to violate Relativity (very unlikely given current empirical evidence) or to drop Realism, namely that physical quantities have well-defined values outside of observations. Quantum Mechanics takes the latter approach.
Only if you use extraneous and quantum mechanical “interpretations”, of which there are several. Another option is to drop non-locality and it seems to me that is what quantum physics do when you add relativity and (arguably) get rid of classical pre-relativity interpretations. See my own answer to Steve Gerrard.
That’s exactly what I’m saying. Violating Relativity/Nonlocality is very unlikely considering current empirical evidence and so the usual view is that realism, i.e. measurement independent properties, is falsified.
It is really not that mysterious, especially if you consider that quantum field theory is relativistic and have universal fields in contrast with the usual classical quantum mechanical language description. So you know that signaling obey the universal speed limit (speed of light in vacuum), and that is what the formulation wants to point out.
Already correlation tells you instantly the state of another subsystem, the oddity is that you can dynamically change a subsystem state under the experiment. It adds to other relativistic unfamiliarity like time dilation, length contraction, space expansion and (arguably) wave function collapse. But no physics is broken, and communication – which is based in signaling in the “light cone” of relativistic causality – will not be faster than the universal speed limit.
Note that it is nothing in the experiment that constrains it to locality though. The fields which produces particle are universal and the Feynman path integral for particle paths is volume filling. “In calculating the probability amplitude for a single particle to go from one space-time coordinate to another, it is correct to include paths in which the particle describes elaborate curlicues, curves in which the particle shoots off into outer space and flies back again, and so forth. … Paths which self-intersect or go backwards in time are not allowed.” Nature has found a niche for oddity which was unfilled under the constraints of relativity.
I have a basic question about this – so I blurt out an inaccurate question :
Einstein chose a convention – Einstein synchronization – where the measured two-way speed of light from point A to point B and back to point A is _assumed_ equal to what would be measured if the speed of light could be measured from point A to point B.
Does the Nobel prize discovery tell us anything deeper about Einstein synchronization, or does it even matter?
https://en.m.wikipedia.org/wiki/One-way_speed_of_light
No, it’s not relevant for this discovery
I loved the trigger warning! Made me laugh.
I’m just getting to the end of Sean Carroll’s Something Deeply Hidden and am largely none the wiser regards the quantum world (although recommend the book, very well written). I also listen to his podcast and have read many books on quantum and my thoughts on it remain just as entangled as they ever were.
Fascinating topic though which is why I keep going back.
Apologies if mentioned before, but if I were to recommend one author on the subject it’d be Carlo Rovelli. Beautiful, beautiful books. The prose is exquisite and his explanations some of the best I’ve read. Not that I understand it much better after reading him mind.
Essentially each of the three physicists tested progressively stronger examples of the conflict between Quantum Mechanics and Realism. Realism being a physics shorthand for the assumption that physical variables have values outside of observation.
Aspect did the earliest tests, Clauser did stronger test with less loopholes. Zeilinger did the strongest test where Realism predicts something is impossible and Quantum theory predicts it always occurs.
So these tests can be seen to show that physical variables are only randomly assigned values upon observation. Very extreme examples include the number of particles in one’s body not being well-defined when not measured.
Non-local realism, yes. But who said the system is non-local?
I’m not sure what you mean. I’m talking about the standard view of these results in the context of quantum theory where the quantities are local, but not considered to obey Realism in the formal physics sense. So Local Non-Realism in fact.
I think the wikipedia article garbles it a bit; the Wu experiment mentioned doesn’t really provide the kind of definitive demonstration of “spooky action at a distance” required, although it was (I think) a necessary technical step.
The question addressed by the bell inequality is whether it is possible that all the results previously explained by quantum mechanics could instead “actually” by accounted for by a “local hidden variable” theory—one where all the mysterious randomness of quantum mechanics is actually predetermined, just by information that we have not yet devised any way to measure. “Local” being an essential word—if actions can happen at a distance, faster than the speed of light, then all bets are off.
The Wu experiment shows a correlation between two particles emitted from a common source. This doesn’t really demonstrate anything funny, because the particles were, after all, produced by a common source. There is nothing mysterious about them being correlated, and although it is in fact a prediction of quantum mecahnics, you can imagine a theory with no randomness reproducing it.
To actually violate the bell inequality—which says that certain experimental results, predicted by quantum mecanicscs, would not be compatible with *any* local deterministic theory—you need to do something which seemingly produces action at a distance. And this effectively relies on having two quantities A and B which are coupled together, so that when you choose to measure property A for particle 1 and property B for particle 2, the results are correlated. At the end of the math it all shakes out that the correlation is so big that if you wanted to believe in a deterministic theory, you would have to believe that when you chose to measure property A for particle 1, it instantaneously changed the behaviour of B for particle 2. At the time of Wu’s experiment they didn’t know exactly what to measure because Bell hadn’t worked out the theory yet, although I think (not an experimentalist) that they presumably could have done it.
To give an analogy: you can go find many pairs of twins where one lives in Australia and one in the US, and if you ask them separately what their favourite food is, many of them will give the same answer. But you don’t think this means that when you asked the first twin, it instantaneously changed the second twins answer! This is like the Wu experiment (I think, I only read the paper quickly.)—although the Wu experiment does give the amazing result that the specific *value* of how often they agree is predicted by quantum mechanics.
Similarly if you took each pair of twins and asked them their favourite colour, they would again often agree. Nothing mysterious.
But the violation of classical expectations, which is verified by the prize-winning experiments, is roughly that *which question* you choose to ask the twin in Australia is correlated with *which answer* you get for the favourite colour in the US—it’s not possible to explain the results of the experiments if you belive they have both worked out their answers in advance.
Note though that it’s not just local determinism that is incompatible with Bell’s inequality or later ones like CHSH and GHZ, but even local stochastic theories. So a theory cannot escape the experiments just with randomness.
It has to either give up Realism or Locality. QM gives up the former. So it’s not just that variables take on values randomly, but that they only do so upon observation/measurement.
Yes, that’s right, my explanation was a bit sloppy.
Hey Sean, no worries your explanation was fine and the correct meaning was implied by your final line “worked out their answers in advance”, with “answers” being the right wording as in “response to the query we have posed”. I just wanted to be explicit about it.
The observer dependence of quantum theory is its most confusing feature.
You have two choices: give up the dated non-relativistic quantum mechanics or the newer and more useful quantum field physics. If you give up the former, which is the natural choice, you can then consider which fits the observed physics best. As far as I know quantum fields are by their very nature non-local, and particles are (resonant) excitations of the field and not isolated entities. Meanwhile, confusing classical wavefunction collapse with action involved in descriptions of reality (realism) is fraught with problems since there isn’t any action taking place in observation – the classical wavefunction is a statistical description. Saying “the number of particles in one’s body not being well-defined when not measured” makes no sense since it would break energy conservation of mass and metabolism – the body has a well defined energy and number of molecules.
Meanwhile, and interestingly, the wavefunction seems to be a physical component of field descriptions. In any case, the relativistic description of wavefunction collapse has been shown to be equivalent to be a random outcome of reference frames under entanglement in order to keep the Planck constant universal. That’s why I mention elsewhere that it arguably may be a relativistic oddity, but here I add that it doesn’t involve particles and their property parameters that not “have values outside of observation”. They just do unfamiliar things when observed, akin to length contraction, in order to preserve physical laws.
There’s a few errors here.
Firstly quantum fields are strictly local. They are essentially defined as local operators and many of their properties follow from their locality. A good book on the subject is Streater and Wightman’s “PCT, Spin and Statistics and all that”.
The number of particles in one’s body not being defined is a straight forward result of quantum field theory where most states are not eigenstates of the particle number operator and so do not have well-defined particle content. Our bodies being in a thermal state are certainly not in an eigenstate of the number operator. I’d recommend Jochen Rau’s book of Thermodyanmics for a nice discussion of this.
Your second paragraph I cannot make sense off. I’m not saying this to be rude, but terminology is being used in a very non-standard way and as a physicist I can’t get a proper meaning out of it. Can you point to a paper discussing what you mean?