Thursday, December 8, 2022

Holographic Wormhole on a Microchip

From Nature, the leading European science journal:
A holographic wormhole in a quantum computer

Physicists have used a quantum computer to generate an entity known as an emergent wormhole. Quantum systems can be linked by entanglement even when separated by extremely long distances. The authors generated a highly entangled quantum state between the two halves of a quantum computer, creating an alternative description, known as a holographic dual, in the form of an emergent wormhole stretched between two exterior regions. They then simulated a message traversing this wormhole. Such exotic physics is part of efforts to reconcile quantum mechanics with the general theory of relativity.

Dr. Quantum Supremacy responds:
Tonight, David Nirenberg, Director of the IAS and a medieval historian, gave an after-dinner speech to our workshop, centered around how auspicious it was that the workshop was being held a mere week after the momentous announcement of a holographic wormhole on a microchip (!!) — a feat that experts were calling the first-ever laboratory investigation of quantum gravity, and a new frontier for experimental physics itself. Nirenberg asked whether, a century from now, people might look back on the wormhole achievement as today we look back on Eddington’s 1919 eclipse observations providing the evidence for general relativity.

I confess: this was the first time I felt visceral anger, rather than mere bemusement, over this wormhole affair. Before, I had implicitly assumed: no one was actually hoodwinked by this. No one really, literally believed that this little 9-qubit simulation opened up a wormhole, or helped prove the holographic nature of the real universe, or anything like that. I was wrong.

That 1919 eclipse was hyped with a NY Times headline: “Men of Science More or Less Agog Over Results of Eclipse Observations”.

Update: Here is the Quanta video.

Almost a century ago, Albert Einstein realized that the equations of general relativity could produce wormholes. But it would take a number of theoretical leaps and a “crazy” team of experimentalists to build one on Google's quantum computer. Read the full article at Quanta Magazine:
Quanta used to be a respectable magazine. As was Nature, which is now filled with woke nonsense.

Monday, December 5, 2022

What is Entanglement?

Entanglement is supposed tobe the essence of quantum mechanics, but I wonder about it. Wikipedia defines:
Quantum entanglement is the physical phenomenon that occurs when a group of particles are generated, interact, or share spatial proximity in a way such that the quantum state of each particle of the group cannot be described independently of the state of the others, including when the particles are separated by a large distance. The topic of quantum entanglement is at the heart of the disparity between classical and quantum physics: entanglement is a primary feature of quantum mechanics not present in classical mechanics.[1]

Measurements of physical properties such as position, momentum, spin, and polarization performed on entangled particles can, in some cases, be found to be perfectly correlated. For example, if a pair of entangled particles is generated such that their total spin is known to be zero, and one particle is found to have clockwise spin on a first axis, then the spin of the other particle, measured on the same axis, is found to be anticlockwise.

It confusingly says it is a "physical phenomenon", and then says it is a property of how quantum states are described. So it is not a physical property. I removed the word "physical".

My bigger issue is "quantum entanglement is at the heart of the disparity between classical and quantum physics". This is conventional wisdom, so it is reasonable for Wikipedia to say this, but it is true?

Classical systems obey entanglement, exactly as it is described here. Suppose you have a system of two balls, and you know their total momentum. Assume that momentum is conserved. Then the balls get separated, and you measure the momentum of one of them. You then know the momentum of the other ball, as it is perfectly correlated and opposite. The momenta must sum to the original total.

You can do the same with angular momentum.

So how is this any different from the quantum entanglement? I do not see any difference.

Anticipating your objections, you might tell me that the quantum momentum and spin are not known until measured, or that Bell's theorem puts limits on certain correlations. Okay, I accept all that, but what does it have to do with the definition of entanglement? Nothing.

Or you might say that entanglement is a nonlocal interaction. Spooky action and all that. But that is a big hoax. Quantum mechanics is a local theory.

A more sophisticated objection says that entanglement is a precious resource that can be used for cryptography, teleportation, and parallel computation. Quantum entangled particles have the necessary magic, and classically entangled ones do not.

This objection is harder to answer, as currently billions of dollars are being spent to try to determine whether any such magic exists. Most say yes, but they have yet to demonstrate anything useful from that magic.

Even if such magic exists, there ought to be a way to define entanglement that makes it clearly a quantum phenomenon, and not a classical one.

Quantum systems are different from classical systems. Bell proved that. The uncertainty principle is different, and so are certain correlations. But I don't see how entanglement is any different.

Lenny Susskind and others have been saying that wormholes and entanglement are the same thing.

YouTube:

Almost a century ago, Albert Einstein realized that the equations of general relativity could produce wormholes. But it would take a number of theoretical leaps and a “crazy” team of experimentalists to build one on Google's quantum computer. Read the full article at Quanta Magazine:
The idea seems to be that if entanglement and wormholes are the same thing, and quantum computers use entanglement to do super-Turing computations, then there should be some wormholes hiding inside a quantum computer. Seems like a joke to me, but I did not read the details.

Update: Peter Woit writes:

The best way to understand the “physicists create wormholes in the lab” nonsense of the past few days is as a publicity stunt ...

I’m hoping that journalists and scientists will learn something from this fiasco and not get taken in again anytime soon. It would be very helpful if both Nature and Quanta did an internal investigation of how this happened and reported the results to the public. Who were the organizers of the stunt and how did they pull it off? ...

his claims in the Quanta video that the result of the Google quantum computer calculation was on a par with the Higgs discovery. Does he really believe this (he’s completely delusional) or not (he’s intentionally dishonest)? ...

Peter Shor says: It seems to me that the string theorists and “it from qubit” community seem to have this unwritten rule that they don’t criticize other members of this community in public.

I used to think that Physics had higher standards than other sciences for truth and professionalism. Apparently not.

Another comment:

I thought you’d be interested to know that the “wormhole created in a quantum computer” story is now being covered in some far-right-wing media. I won’t name them here (they’re very far-right sites, not sure if you’d allow a link here), but they’re essentially saying “isn’t this manifestly stupid? See? Why should we believe scientists when they publish bullshit like this?” and essentially use the story to argue that scientists and science journalists are all a bunch of idiots, hence why should we trust them on vaccines/climate change etc.

This is another consequence of bad publicity stunts like this: it erodes trust in scientists.

Here is one such site. It is so disreputable that Google confiscated its domain name. Possibly the most censored site in the world. It just quotes a NY Times tweet, a Google tweet, a Reuters story, and a couple of more tweets, and adds:
This is very obviously fake and it’s goofy that people think it’s real.
I agree with that. It is goofy that people think that this research is real.

Thursday, December 1, 2022

Entanglement Discovered in a Quantum Computer

Lenny Susskind and others have been saying that wormholes and entanglement are the same thing.

YouTube:

Almost a century ago, Albert Einstein realized that the equations of general relativity could produce wormholes. But it would take a number of theoretical leaps and a “crazy” team of experimentalists to build one on Google's quantum computer. Read the full article at Quanta Magazine:
The idea seems to be that if entanglement and wormholes are the same thing, and quantum computers use entanglement to do super-Turing computations, then there should be some wormholes hiding inside a quantum computer. Seems like a joke to me, but I did not read the details.

See Peter Woit for details. At least one physicist calls it a publicity stunt. The quantum computer researchers have burned a lot of money, and need something to show for it.

Update: A comment:

Even if the headline isn’t strictly accurate (a topic for another time, although I think you’re splitting hairs here), what’s the harm? It’s a cool-sounding result which gets people interested in theoretical physics, science more generally. As long as science journalists are driving interest and engagement, I think they’re doing a good job. If you want to discuss bad science journalism, surely a better use of your time would be all the anti-science fake news coming from the populist right in the U.S.
I suspect that this view is common. Over-hyped phony stories generate interest and funding. If you want to be a good Leftist, you should not call out Leftist lies. Instead you should devote that energy to attacking right-wingers!

Update: Scott Aaronson admits that the wormhole story is a big hoax, promoted by physicists who should know better. He also discusses a new paper saying that quantum supremacy is impossible. He says it is no surprise to experts in the field who have known since 2016 that scaling up quantum computers will not work. He is still a believer:

So, though it’s been under sustained attack from multiple directions these past few years, I’d say that the flag of quantum supremacy yet waves. The Extended Church-Turing Thesis is still on thin ice.
That is, he says that he has not been proved wrong yet. Okay, but he hasn't been proved right either.

Monday, November 28, 2022

Aharonov–Bohm effect does not Prove Nonlocality

I heard the suggestion that the Aharonov–Bohm effect proves a form of quantum nonlocality.
The Aharonov–Bohm effect, sometimes called the Ehrenberg–Siday–Aharonov–Bohm effect, is a quantum mechanical phenomenon in which an electrically charged particle is affected by an electromagnetic potential (φ, A), despite being confined to a region in which both the magnetic field B and electric field E are zero.[1] The underlying mechanism is the coupling of the electromagnetic potential with the complex phase of a charged particle's wave function, and the Aharonov–Bohm effect is accordingly illustrated by interference experiments.

The most commonly described case, sometimes called the Aharonov–Bohm solenoid effect, takes place when the wave function of a charged particle passing around a long solenoid experiences a phase shift as a result of the enclosed magnetic field, despite the magnetic field being negligible in the region through which the particle passes and the particle's wavefunction being negligible inside the solenoid. This phase shift has been observed experimentally.[2]

So the effect depends on the potential, and not just the fields.

The potential and fields are all locally defined, so what is the problem?

The problem is that only the fields are directly observable, and there is considerable discretion in defining the potential. Sometimes the potential is defined to satisfy a distant condition. This is allowed, because gauge symmetry means it has the same physical effect.

From the viewpoint of differential geometry, the potential is a connection on a complex line bundle, and is a purely local object. It is more fundamental than the fields.

The paradox is that an electron can interfere with itself after going around a non-null-homotopic loop with a flat complex line bundle. Arguably there is something nonlocal about that. I don't think so. It is not like action-at-a-distance at all.

Friday, November 25, 2022

Electrons Are Spinning

Scientific American reports:
Quantum Particles Aren’t Spinning. So Where Does Their Spin Come From?

A new proposal seeks to solve the paradox of quantum spin ...

But despite appearances, electrons don’t spin. They can’t spin; proving that it’s impossible for electrons to be spinning is a standard homework problem in any introductory quantum physics course. If electrons actually spun fast enough to account for all of the spinlike behavior they display, their surfaces would be moving much faster than the speed of light (if they even have surfaces at all). Even more surprising is that for nearly a century, this seeming contradiction has just been written off by most physicists as yet another strange feature of the quantum world, nothing to lose sleep over.

No, this is wrong. Electrons do spin. You only get that paradox if you assume that electrons are very tiny spheres or point particles, but quantum mechanics teaches that electron are non-classical entities with wave-like properties.

The article goes on to give the history of quantum spin, and how crucial it is for understanding chemistry and many other things.

But all of these fabulous discoveries, applications, and explanations still leave Goudsmit and Uhlenbeck’s question on the table: what is spin? If electrons must have spin, but can’t be spinning, then where does that angular momentum come from? The standard answer is that this momentum is simply inherent to subatomic particles, and doesn’t correspond to any macroscopic notion of spinning.

Yet this answer is not satisfying to everyone. “I never loved the account of spin that you got in a quantum mechanics class,” says Charles Sebens, a philosopher of physics at the California Institute of Technology.

No, this is silly. The QM textbooks teach that position, momentum, energy, angular momentum, and spin are observables that correspond to the classical variables, but cannot be taken literally about electrons as point particles, as the uncertainty principle prevents such a literal treatment. There is not really any difference between spin and the other variables in this respect.

I previously posted Electrons do spin.

Peter Woit explains:

Despite what Sebens and Carroll claim, it has nothing to do with quantum field theory. The spin phenomenon is already there in the single particle theory, with the free QFT just providing a consistent multi-particle theory. In addition, while relativity and four-dimensional space-time geometry introduce new aspects to the spin phenomenon, it’s already there in the non-relativistic theory with its three-dimensional spatial geometry.
Asking whether electrons really spin is a like asking whether they orbit the nucleus of an atom. A century ago, physicists tried to model an atom as classical electron orbits, and figured out that it doesn't work. You need a quantum model. But it is still correct to say that the electrons orbit the nucleus.

Wednesday, November 23, 2022

TV Show on Zero and Infinity

I just watched the latest PBS TV Nova on Zero to Infinity:
Discover how the concepts of zero and infinity revolutionized mathematics.
It was stupid and boring.

A Black woman professor narrated. They always seems to find Blacks and women for these shows. Not sure why. Does PBS have a lot of Black viewers? Is it trying to get more?

I doubt it. My guess is that the typical WHite liberal PBS viewer gets a good feeling of social justice when a Black woman is lecturing.

Much of the show was about the invention of the Zero. It attributed it to India, and said that Persians and other middle easterners brought it to Europe.

But what was the invention? The use of 0 as a placeholder, or as a counting number, or as a number on the same footing as other numbers?

I looked for some statement from India or Persia saying something like: The counting numbers are { 0, 1, 2, ... }, and for any such numbers, A + B = B + A.

That would show that the author considered 0 to be a number just like 1 and 2.

But on the contrary, the show itself did not even do that. The moderator kept referring to the counting numbers as 1, 2, 3, ..., and not including 0.

Any who says that has still not grasped the invention of 0. 0 is a counting number. If I ask you how many apples you have, and you have none, then you answer 0. Maybe you answer -2, if you owe 2 apples. If you say there is no answer, then you have not accepted the 0.

Even the business pages of a typical newspaper rarely treat zero as a number. It will often avoid it with various euphemisms.

The show eventually moved on to infinity, but that was not any better. It gave a faulty version of Cantor's diagonal proof of the uncountability of the reals.

Suppose you list .4, .49999..., .009, .0009, ... . It said to add 1, mod 10, to each diagonal digit. That gives .50000. That is the same real number as the 2nd item on the list, with a different decimal representation.

A good proof must somehow take into account that real numbers can have two decimal representations.

Cantor's orginal proof did not use diagonalization.

The show went on to Zeno's paradoxes and Hilbert's hotel. It was all fairly trivial.

Since it tried to trace the origin of the zero, I thought that it might tell us who invented infinity?

It did talk about approximating π as a limit of an infinite sequence. I guess that idea goes back to the ancient Greeks. The invention of infinitesmal calculus required limits. Those ideas were made rigorous centuries later. Cantor introduced the concept of different infinite cardinals. I am not sure who really first had the modern concept.

These PBS shows appears to be expensively produced, but you can find lots of free YouTube videos that explain the math much better, and are more entertaining.

Monday, November 21, 2022

Making Finitary Deductions About Infinities

That is my 5-word definition of Mathematics. It is what distinguishes Math from every other field.

Some say that Math is the study of numbers, or the use of symbolic notation. But Music uses symbolic notation, and numbers are used by all the hard and soft sciences.

None of the empirical sciences ever encounter infinities. Cosmologists may talk about the universe having infinite extent, but there is no reason to believe that, and we cannot observe that. We only observe finite quantities.

And the sciences never make a finitary deduction either. An experiment might convince us of some fact, but it is really just evidence that makes an outcome 99% likely, or something like that. The experiment has to be refined and redone to become more and more sure of it.

Math has infinities all over the place. This is obviously true about work on limits, but it is also true about elementary statements like the Pythagorean Theorem. There are infinitely many possible right triangles, and the theorem gives a formula about all of them.

Even with all the infinities, the proofs always use a finite set of steps from a finite number of axioms. The proofs about the infinities are always strictly finitary.

Here is the Wikipedia definition of Mathematics:

Mathematics (from Ancient Greek μάθημα; máthēma: 'knowledge, study, learning') is an area of knowledge that includes such topics as numbers (arithmetic and number theory),[2] formulas and related structures (algebra),[3] shapes and the spaces in which they are contained (geometry),[2] and quantities and their changes (calculus and analysis).[4][5][6] Most mathematical activity involves the use of pure reason to discover or prove the properties of abstract objects, which consist of either abstractions from nature or — in modern mathematics — entities that are stipulated with certain properties, called axioms. A mathematical proof consists of a succession of applications of some deductive rules to already known results, including previously proved theorems, axioms and (in case of abstraction from nature) some basic properties that are considered as true starting points of the theory under consideration.

Mathematics is used in science for modeling phenomena, which then allows predictions to be made from experimental laws. The independence of mathematical truth from any experimentation implies that the accuracy of such predictions depends only on the adequacy of the model. Inaccurate predictions, rather than being caused by incorrect mathematics, imply the need to change the mathematical model used.

Here is Britannica:
mathematics, the science of structure, order, and relation that has evolved from elemental practices of counting, measuring, and describing the shapes of objects. It deals with logical reasoning and quantitative calculation, and its development has involved an increasing degree of idealization and abstraction of its subject matter. Since the 17th century, mathematics has been an indispensable adjunct to the physical sciences and technology, and in more recent times it has assumed a similar role in the quantitative aspects of the life sciences.
Here are some dictionaries:
The abstract science of number, quantity, and space. -- Oxford

An abstract representational system studying numbers, shapes, structures, quantitative change and relationships between them. -- Wiktionary

The science of numbers and their operations, interrelations, combinations, generalizations, and abstractions and of space configurations and their structure, measurement, transformations, and generalizations. -- Merriam-Webster

The study of the measurement, relationships, and properties of quantities and sets, using numbers and symbols. -- dictonary.com

The science that deals with the logic of shape, quantity and arrangement. -- Live science

The study of numbers, shapes, and space using reason and usually a special system of symbols and rules for organizing them. -- Cambridge

These are pretty good, but do not distinguish Math from science well. Yes, Math is an area of knowledge that includes numbers, but the mathematicians do proofs, with infinite numbers and finite arguments.

Thursday, November 17, 2022

Sean M. Carroll Goes Woke on Sex

Sean M. Carroll has become one of the leading expositors of advanced Physics, but he has a lot of strange views that will make you skeptical of whatever he tells you.

The biggest is that he believes in the many-worlds alternative to quantum mechanics. This is a belief that anything is possible, and that nothing is more likely than anything. It is a complete rejection of all modern science.

He has his own rationalization that is mostly circular reasoning.

In his latest Ask Me Anything podcast, he says that he does not see a moral justification for parents spending money on their children's education. He says all children should get the same education.

He is married with no kids.

He is welcome to his opinions, but he does not describe the American situation accurately. In California, his home state until recently, the schools get about 50% of the state budget, and the poor districts get at least as much as the rich districts. The rich are not getting any better educational opportunities.

Some rich parents do send their kids to expensive schools, but the educational opportunities are not much different from public schools.

He has also joined the sex-deniers who say that biological sex is not binary. Biology professor Jerry Coyne is a big fan of Carroll, because of what he says in favor of determinism and against libertarian free will, but schools him on biological sex.

In reality, what they are trying to do is the reverse: adjust scientific reality so that it aligns with social justice. That is, if sex is a spectrum and not binary, then people of different genders can somehow feel that they are in harmony with biological reality. But that’s an example of the “appeal to nature.” The rights of people of different genders, including transsexual people, do not depend on the developmental biology of sex, or of any observations in nature about sex dichotomies.

I’m not going to discuss my claim that sex is binary; I’ve talked about it at length, as did Luana Maroja in her piece at Substack. I’ll just put it out there that the going biological definition of sex is that there are two sexes in vertebrates: males (who produce small mobile gametes) and females (who produce large, immobile gametes). There is no group that produces intermediate types of gametes that can unite with other gametes, so there is nothing beyond these two sexes.

Carroll is not a biologist. He is not to be confused with the somewhat more accomplished scientist, Sean B. Carroll, who really is an expert biologist.

I assume that Sean M. Carroll is smart enough to know the difference between male and female. But it appears that he is willing to recite nonsense in order to please his Leftist Woke fans.

I suggest keeping this in mind when listening to him. He sometimes gives pretty good explanations of textbook physics, but his opinions on big picture physics are dubious, and his moral and politcal opinions are garbage.

Monday, November 14, 2022

Einstein and the Equivalence Principle

New paper:
Einstein's Happiest Moment: The Equivalence Principle
Paul Worden, James Overduin

Einstein's happiest thought was his leap from the observation that a falling person feels no gravity to the realization that gravity might be equivalent to acceleration. It affects all bodies in the same way because it is a property of spacetime -- its curvature -- not a force propagating through spacetime (like electromagnetic or nuclear forces). When expressed in a way that is manifestly independent of the choice of coordinates, this idea became General Relativity. But the ground for what is now known as the "equivalence principle" was laid long before Einstein, affording a fascinating example of the growth of a scientific idea through the continuous interplay between theory and experiment.

As this article and Eikipedia explain, the equivalence principle goes back centuries. Einstein was very happy about using it in a 1907 paper, but it was not because gravity was a realization of curvature, as he did not even know what curvature was at the time.

It is my understanding that what Einstein was actually happy about was that he figured out a way to use the principle to use special realtivity to show gravitational time dilation.

Special relativity is often described as a theory about constant velocity, but back during the early days, say 1995-2010, it was widely understood to cover accelerating particles also. Poincare proposed a couple of relativistic gravity theories, but the geometry was not understood.

Einstgein figured out how to sidestep having a gravity theory, by saying that gravity was like non-gravitational acceleration. That was enough to figure out clocks in a gravitational field.

People often say that general relativity is needed for GPS navigation, but I don't think that is true. It only needs special relativity, and this trick of Einstein.

As far as I know, this idea of Einstein was his own, and not plagiarized from anyone else. Maybe that is why he was so happy about it.

Thursday, November 10, 2022

Probability is Subjective

Ulrich J. Mohrhoff writes:
With Mermin, I also hold this truth to be self-evident (though it took me some time to get there), that probabilities are intrinsically subjective. ...

Mermin invokes the celebrated probabilist Bruno de Finetti, who wrote: “The abandonment of superstitious beliefs about the existence of Phlogiston, the cosmic ether, absolute space and time. . . , or Fairies and Witches, was an essential step along the road to scientific thinking. Probability too, if regarded as something endowed with some kind of objective existence, is no less a misleading misconception, an illusory attempt to exteriorize or materialize our actual probabilistic beliefs.”

Taking the mind-independent existence of the external world for granted, de Finetti holds that there is no place for probability in such a world, any- more than there is for Phlogiston and the rest.

I agree with this, but do not deny the importance of probability.

All scientific theories are inherently probabilistic. Even classical celestial mechanics, the textbook example of the clockwork deterministic universe, was always probabilistic in practice. Observations in the sky always had errors, and predictions had uncertainty. Linear regression was invented to make probabilistic predictions about celestial orbits.

Monday, November 7, 2022

Quantum Computing Skeptic gives Lecture

Gil Kalai gave a lecture on the impossibility of quantum computers, summarized here:
My argument for the impossibility of quantum computers lies within the scope of quantum mechanics and does not deviate from its principles. In essence, the argument is based on computational complexity and its interpretation, and it is discussed in-depth in my papers which also include a discussion of general conclusions that derive from my argument and relate to quantum physics, alongside suggestions of general laws of nature that express the impossibility of quantum computation.

My argument mostly deals with understanding quantum computers on the intermediate scale (known as NISQ computers, an abbreviation of Noisy Intermediate Scale Quantum), that is, quantum computers of up to at most several hundreds of qubits. It is expected that on this scale we will be able to construct quantum codes of a quality sufficient for the construction of bigger quantum computers. It is further expected that on this scale the quantum computer will achieve computations far beyond the ability of powerful classical computers, that is, will achieve quantum computational supremacy. The Google’s Sycamore computer is an example of a noisy intermediate-scale quantum computer.

As specified later, it is my argument that NISQ computers cannot be controlled. Hence:

  1. Such systems cannot demonstrate significant quantum computational advantage.
  2. Such systems cannot be used for the creation of quantum error-correcting codes.
  3. Such systems lead to non-stationary and even chaotic distributions.

Note that he does not say that quantum mechanics is wrong. He denies that quantum computing is a necessary consequence.

A lot of smart people and a lot of research funding say that he is wrong.

Maybe I am just a contrarian, but it seems to me that they should have been able to prove him wrong by now. They have not.

Thursday, November 3, 2022

Dr. Bee Make Bad Argument for Superdeterminism

Jonte R. Hance and Sabine Hossenfelder posted another short argument for superdeterminism, without admitting that superdeterminism is their real goal.

It starts out complaining that a Physics Nature article about Bell Tests was not completely precise. The Bell Tests prove that quantum mechanics experiments are inconsistent with local hidden variable theories.

As Bell and others have pointed out, there are some subtle assumptions: that the experimenter can make free choices (no superdeterminism), that future does not cause the past (no retrocausality), and that experiments have single outcomes (no many-worlds). All of these possibilities are crazy, and no serious person would believe in them. So these are reasonable assumptions.

If their only point was that a precise statement would mention these possibilities, that would be fine. But they go further.

They say that some people believe that they have the free will to do the measurements they choose, and then "It is, in hindsight, difficult to understand how this as- sociation came about." That is, they do not understand how people could think that they have the free will choose equipment settings.

Understanding the implications is even more important now that the experimentally observed violations of Bell’s inequality have been awarded the 2022 Nobel Prize in Physics. Contrary to what is of- ten stated, these observations do not demonstrate that “spooky action at a distance” is real and nature therefore non-local.
The Nobel citation did not say that spooky action is real, or that there is anything wrong with quantum mechanics.
Rather, the observations show that if nature is local, then statistical independence must be violated. We should therefore look for independent experimental evidence that can distinguish the two different options: non-locality and statistical independence, or locality and violations of statistical independence.
No, they are wrong here. The Bell observations show that if nature is local, then the theory must be a non-classical theory like quantum mechanics, or else we have one of the crazy loopholes like superdeterminism, retrocausality, or many-worlds. Saying non-classical is essentially the same as saying no local hidden variables.

Their deceptive title is "Bell's theorem allows local theories of quantum mechanics". That is completely correct statement, as local quantum mechanics is what all the textbooks teach. But what the body of the paper says is that Bell's theorem allows local superdeterminism, and that is the opposite of quantum mechanics. There is no superdeterministic theory of quantum mechanics.

Believing is superdeterminism is essentially a rejection of all science in the last millennium. So is retrocausality and many-worlds. You can believe in it if you want, but it is quite wrong to say that it is required by locality.

Dr. Bee has started expanding her podcasts to covering science news. She does a competent job, and she is very knowledgeable about Physics. But how can you trust anyone who believes that no one has any free will to do experiments, and that every randomized trial is fake?

Tuesday, November 1, 2022

String Theory may Explain Consciousness

New paper:
Recent proposals in quantum gravity have suggested that unknown systems can mediate entanglement between two known quantum systems, if the mediator itself is non-classical. This approach may be applicable to the brain, where speculations about quantum operations in consciousness and cognition have a long history. ...

Our findings suggest that we may have witnessed entanglement mediated by consciousness-related brain functions. Those brain functions must then operate non-classically, which would mean that consciousness is non-classical.

Roger Penrose was widely mocked for advocating ideas like this. No one has made much progress on the problem of consciousness, and I am skeptical about this, and the next story.

Separately, I heard a rumor that a string theory prediction about holography has been confirmed in a quark-gluon plasma:

a big (not so well-kept) secret I heard the other day. Story goes that some accelerator lab (Fermi?) has been busy smashing heavy ion beams (Au nuclei?) together, creating a quark-gluon plasma. and measuring some QCD observable (say "A") of the chaos that ensues. According to a "holographic principle" (an AdS/CFT-type correspondence), A is equivalently described as some GR (or QG?) observable ("B") on the system comprised of a black hole that arises in the 5D spacetime forming the bulk (interior) of the shell on which the q-g plasma lives as a solution to the QCD equations. The Einstein equations for the evolution of the hole are solvable and B can be calculated. The lab has apparently successfully verified that the "predictions" given by the calculations of B agree with measurements of A. (Secret was leaked by Susskind in a recent talk which can be found on YouTube... my version includes a little reading between the lines and may not be completely accurate.... so I'll speculate further and guess that A is something like rate of change of temperature and B is something like rate of change in entropy, i.e., area of the event horizon. The plasma cools and the hole shrinks due to Hawking radiation?)

This is mind-blowing and, I think, of importance equal to, if not surpassing, that of the confirmation of GR by deflection of starlight during the 1919 eclipse... or of the finding of the Higgs.
I will be watching for more on this. Lenny Susskind gave some related lectures here and here.

Peter Woit has a new post trashing some related claims to testing string theory.

Scott Aaronson is claiming some new results about the complexity of the AdS/CFT correspondence. You have to skip over his previous blog post, where he describes the progressive thesis that he is aligned with:

just like at least a solid minority of Germans turned out to be totally fine with Nazism, however much they might’ve denied it beforehand, so too at least a solid minority of Americans would be fine with — if not ecstatic about — The Handmaid’s Tale made real. Indeed, they’d add, it’s only vociferous progressive activism that stands between us and that dystopia.

And if anyone were tempted to doubt this, progressives might point to the election of Donald Trump, the failed insurrection to maintain his power, and the repeal of Roe as proof enough to last for a quadrillion years.

I have never even heard of any Trump supporters who want anything like The Handmaid's Tale. Only liberals watch the show and read the bood, as far as I know. Also there was no insurrection, and no repeal. Abortion law was merely returned to the democratic process. Aaronson sounds like a parody of a left-wing lunatic. I sometimes wonder if he is serious.

Monday, October 31, 2022

What was that Bell Nobel Prize For?

The Bell fans lobbied for a Nobel Prize for 30 years, and they finally got it, so are they happy?

No. See this video, Tim Maudlin Corrects the 2022 Nobel Physics Committee About Bell's Inequality. He says the Nobel citation missed the point.

I don't want to pick a fight with Maudlin, as he is a very smart guy who explains this stuff very well. He has sharp disagreements with others about Bell's theorem, and I describe them here.

Another recent Maudlin video says:

[47:00] The theorem of Bell [and confirming experiments] is the most astonishing thing in the history of Physics.
Among other things, he gives a very good explanation of what is wrong with superdeterminism, as a Bell loophole. Here is a shorter interview.

Here is my view. When quantum mechanics (QM) was discovered in 1926, a lot of smart people wondered whether was a new type of theory, or if the uncertainties were just disguising an underlying classical theory. John von Neumann was the world's smartest man, and he convinced himself in 1932 that QM was different from any classical theory. Einstein co-wrote a 1935 paper speculating that QM might be completed by adding elements of physical reality. Bell showed in 1964 that the difference between QM and a classical theory could be quantified, and that was later confirmed experimentally by Clauser and the other Noble prize winners.

So the Bell work is no big deal, as it only confirmed what everyone thought.

Maudlin and the other Bell fans have another view. To be fair to Maudlin, I suggest his paper, What Bell Did, and his exchange with Werner, here and here.

He correctly says that Bell assumed locality, hidden variables, and statistical independence. Statistic independence is assumed by all of science, and is reasonable. Hidden variables are just the Einstein elements of physical reality, and he and Bell argue that any reasonable theory would have them. That leaves locality. The experiments showed that the Bell inequalities are violated, so that means that nature must be nonlocal.

He is right that if you accept hidden variable theory then you have to accept nonlocality. I just do not accept hidden variables.

He is also right that the Nobel citation failed to endorse the nonlocality conclusion.

There are also the superdeterminism and many-worlds loopholes, but Maudlin and the Nobel committee are right to ignore these. That leaves you with a choice -- you can have locality or hidden variables, but you cannot have both.

Maudlin would say that I and the Nobel committee suffer from a misconception that has gone on for decades.

It would take some very compelling evidence to convince me of nonlocality. As Maudlin says, if you snap your fingers, do you believe that what happens in your hand can depend on what happens in a distant galaxy? I say of course not, but Maudlin accepts that.

Wouldn't we see some examples of action-at-a-distance?

He gives an example pointing to nonlocality in the Aharonov–Bohm effect. I do not agree, but it requires technical explanation, and maybe I will post separately on it.

Maudlin says:

The reality of nonlocality has been settled. [3rd video, 18:45]
So what is nonlocal? There is no way to change one particle, and have that affect an observable of a distant particle. So the only things that are nonlocal are the mythical hidden variables.

Wikipedia describes Bell's theorem:

Bell's theorem is a term encompassing a number of closely related results in physics, all of which determine that quantum mechanics is incompatible with local hidden-variable theories given some basic assumptions about the nature of measurement.
Maudlin wants to remove the term "hidden-variable" from the picture, and deny that Bell made such an assumption. You can read Bell's 1964 original paper, and see for yourself that he assumes hidden variables. In later papers he called them "beables" and tried to argue that they could be assumed from first principles. But they have to be assumed somehow.

Discussions of Bell's Theorem sometimes get sidetracked by issues of probability and determinism. Some say Bell proved the world is indeterministic. Some say Einstein EPR objected to indeterminism. This is a red herring. There is some truth to it, but it has to be stated carefully, or it is misleading. Maybe I will make another post on this issue. I would say that Bell proved the impossibility of local hidden variable theories, whether they are deterministic or stochastic. Ultimately all theories are stochastic anyway, as all measurements and predictions have errors.

Friday, October 28, 2022

Why Many-Worlds cannot have Probabilities

More and more physicists say that the Many Worlds Interpretation (MWI) is their favorite interpretation of quantum mechanics (QM). They usually argue that it is simpler, more scientific, more philosophically sensible, and obviously preferable to the nonsensical and inconsistent Coperhagen Interpretation (CI). They stress that it is an interpretation, making all the same predictions as QM/CI. All of this is false. MWI does not any predictions that are verifiable by experiment. It says all outcomes are possible. To get a measurable prediction, you have to somehow say that some outcomes are more probable than others. The MWI theory fails to say any worlds are more probable than others. So to get probabilities, you need the Born Rule.

Some have argued that there is a way to get the Born Rule in MWI, but the mainstream opinion is that those arguments are circular. For example, see this recent paper:

How Do the Probabilities Arise in Quantum Measurement? Mani L. Bhaumik ...

So far, only some ad hoc propositions such as Born’s rule [5] have allowed the physicists to predict experimen- tal results with uncanny accuracy of better than a part in trillion [6]. But the basic cause of this essential rule has remained shrouded in a veil of mystery. One of the prominent investigators in this field, Wojciech Zurek has attempted to provide a derivation of the Born rule per- haps to make his program comprehensive [7]. But it has faced a stiff resistance from some foremost investigators including one of the giants of physics of our time, Nobel laureate Steven Weinberg.

In his classic textbook, Lectures on Quantum Mechan- ics, Weinberg states [8, p. 92], “There seems to be a wide spread impression that decoherence solves all obstacles to the class of interpretations of quantum mechanics, which take seriously the dynamical assumptions of quantum mechanics as applied to everything, including measure- ment.” Weinberg goes on to characterize his objection by asserting that the problem with derivation of the Born’s rule by Zurek “is clearly circular, because it relies on the formula for expectation values as matrix elements of operators, which is itself derived from the Born rule.” In [8, p. 26] he questions, “If physical states, including observers and their instruments, evolve deterministically, where do the probabilities come from?" Again in his recent book [9, p. 131], Weinberg questions, “So if we regard the whole process of measurement as being governed by the equations of quantum mechanics, and these equations are perfectly deterministic, how do probabilities get into quantum mechanics?

Maximilian Schlosshauer and Arthur Fine remark [10], “Certainly Zurek’s approach improves our understanding of the probabilistic character of quantum theory over that sort of proposal by at least one quantum leap.” However, they also criticize Zurek’s derivation of the Born’s rule of circularity, stating: “We cannot derive probabilities from a theory that does not already contain some probabilistic concept; at some stage, we need to “put probabilities in to get probabilities out.”

The author goes on to argue that he has solved these problems, and found a solution that has eluded physicists since 1926.

Maybe so, but I doubt it. The paper looks as if it reviews some standard QM theory, and shows that questions naturally have probabilities. Yes, sure QM has probabilities. It is when you make the leap to deterministic unitary theory and MWI that the probabilities disappear.

Weinberg is dead, so we cannot ask him if this paper solves the problem. I doubt that others are persuaded, but we shall see.

In the mean time, I cite this as proof that MWI currently has no way of saying that any outcome is more probable than any other. In other worlds, completely usuless as a scientific theory. Anyone who subscribes to it is a crackpot.

Unless this paper solves all the MWI problems. If the MWI advocates endorse this paper as a solution to their problems, then I will take another look at it. But that will not happen. They will just go on ignoring the fact that MWI cannot make any testable prediction.

Here is a podcast interview of Hugh Everett's biographer. He is described as having a hard life, and his MWI theory, which he preferred to call the "relative state", was not well appreciated in his lifetime. The interviewer, Steve Hsu is a believer.

They acknowledge that some journals refuse to publish anything in favor of MWI, and maybe half of physicists regard it as outlandish and ridiculous. But they also argue that it is essentially the same as decoherence theory, and that is very well accepted.

It is not the same. Decoherence is an attempt to understand how the wave function collapses, in the absence of an observer. Copenhagen followers regard it as a straightforward extension of known QM. MWI posits that decoherence is accompanied by a split in the universes, making many more.

Hsu says that the whole universe does not necessarily split; just the observer splits. Okay, but he really wants MWI for cosmology problems where there is no observer. The splits must be huge.