Brian Cox Explains Quantum Physics

New video: Physicist Brian Cox explains quantum physics in 22 minutes:

"Quantum mechanics and quantum entanglement are becoming very real. We're beginning to be able to access this tremendously complicated configuration space to do useful things."

In just 22 minutes, physicist and professor Brian Cox unpacks the subatomic world, beginning with the theories as we understand them today.

I do not think these explanations are helpful. He says the theory was not practical until recently, when quantum computers started being built.

15:13 Now you go back a few decades 15:16 then I think you could say that the interpretations 15:21 of quantum mechanics 15:23 are very interesting and very important, 15:28 because we're talking about the nature of reality. 15:30 But you might say, well, it doesn't really matter 15:33 so much practically, right? 15:35 If that now, I have a lot of colleagues in physics 15:38 who would, I think rightly hate that description 15:41 because what we're trying to do 15:42 is understand reality, what physics is. 15:45 But now particularly, I think, with the possibility 15:50 of building quantum computers, 15:52 this attempt to understand how large systems 15:55 of quantum mechanical objects behave 15:57 is becoming extremely important, 15:59 because a quantum computer 16:02 is a device which is built out of qubits.

No, the annual world economy has about a trillion dollars based on quantum mechanics. The theory is essential for transistors, silicon chips, lasers, led lights, solar panels, cameras, digital displays, and many other technologies. So the theory has been very practical for 70 years. On the other hand, no one has demonstrated any utility for quantum computers.

He spends time explaining that quantum physics involves probabilities, wave effects, and predictions from conservation laws. But none of these are unique to quantum mechanics. I do not think he explained the subject at all.

The most important new ideas in quantum mechanics are that (1) observables are non-commuting operators; and (2) electrons, and everything else, have wave properties but are observed as eigenvalues. Those are the quantum mysteries.

All the other stuff, the probabilities, the Schroedinger cats, the supposed nonlocality, the entanglement, the superpositions, etc., just are not that mysterious. Cox is a leading Physics expositor, and he can do better.

Physicist G. tHooft got a Breakthrough Prize and he was interviewed about his strange quantum ideas.

Quantum mechanics is the possibility that you can consider superpositions of states. That’s really all there is to it. And I’d argue that superpositions of states are not real. If you look very carefully, things never superimpose. [Erwin] Schrödinger asked the right questions here: You know, take my cat, it can be dead; it can be alive. Can it be in a superposition? That’s nonsense!

And he was quite right. People shouldn’t continue to insist that a dead cat and a live cat superimpose. That’s complete nonsense ...

What I’m saying is: we must unwind quantum mechanics, so to speak, as to see what happens underneath. And until the quantum technologists start doing that, I believe they won’t make really big progress.

He believes in superdeterminism as a way to save locality. He complains that no one takes him seriously.

His ideas are too silly to take seriously. He says QM is just being able to consider more than possibility. What is quantum about that? Classical mechanics allows considering multiple possibilities. And superdeterminism is really kooky.

Physicist Ethan Siegel is usually pretty good, but he rambles about the multiverse in his latest video.

At 1:18:50, he says particle spin has just a discrete degree of freedom, because it is just up or down, in each of the three dimensions. But decay into fixed-energy photon has a continuous degree of freedom, because photons can go in any direction. I did not follow that. Spin can also be in any direction. Spin is different from momentum in that different directions do not commute, and spin magnitude can only have discrete values. But in his example, both the momentum and spin have a known magnitude. So I think he is making a mistake here, but I could be wrong.

My real objection is to all the multiverse junk.

54-year-old Paper wins Breakthrough Prize

A $3 million prize was just announced:

Special Breakthrough Prize in Fundamental Physics

Gerard 't Hooft, winner of the Special Breakthrough Prize in Fundamental Physics, is one of the world’s most pre-eminent theoretical physicists. In the early 1970s he made crucial contributions to the foundations of what would later become known as the Standard Model of the subatomic particles. He proved that Yang-Mills theories (the mathematical framework underlying theories of both the weak and strong nuclear forces) make sense when treated quantum mechanically – that they can give finite, calculable results rather than meaningless infinities – thus validating theories which became central to the Standard Model. He made several crucial contributions to understanding the theory of the strong force, including resolving a major problem involving the masses of particles through special field configurations called instantons; he developed new mathematical tools for studying strongly interacting quarks; and he introduced the fruitful approach of studying the strong force by imagining it is mediated by many more varieties of quarks and gluons than it actually is. These and other contributions helped establish the Standard Model as a workable theory and provided powerful tools for calculating its predictions. 't Hooft has studied the quantum effects that can explain how information is processed in black holes, which led to the development of the holographic principle in cosmology, and possibly to new alternative ways to interpret quantum mechanics.

His 1971 paper on how to renormalized gauge fields was indeed a breakthrough, and probably did more to create the Standard Model than anything else. But it is now 54 years later.

I do not think that very many people realize what a failure theoretical physics has been for the last 50 years. It is hard to find anthing that can be called a breakthrough. The Golden Age of Physics is long gone.

Consciousness and Physics

Sam Harris has a big following, mainly promoting Atheism, Eastern religious meditation, Trump-hating politics, and lack of free will. It turns out that his wife is more preoccupied with consciousness than he is, and announced an audio documentary on it. You can hear free interviews on it here and here.

Her main point is that if consciousness is fundamental, then that would be a paradigm shift.

She expects physicists to be experts on what is fundamental, so she interviews a bunch of them for the documentary, including Brian Greene and Sean M. Carroll.

These guys are odd choices, because they do not believe in free will, and one cannot have very much consciousness without free will. To me, the ability to make decisions is at the core of my consciousness.

Here is Greene's view:

Brian Greene, a prominent theoretical physicist known for his work on string theory, does not believe in free will in the traditional sense. He argues that the universe operates under deterministic physical laws, leaving no room for human agency to override them. In his book Until the End of Time (2020), Greene asserts that everything—thoughts, actions, choices—is the result of particles and fields obeying quantum-mechanical and classical rules. During a 2020 Harvard Science Center lecture, he said, “We are made of these exquisitely ordered, wonderfully choreographed particles of nature governed fully by the physical laws, no free will whatsoever.” He sees free will as an illusion, a sensation we experience, but not a reality grounded in physics. In a 2014 blog post (Atheism and the City), he’s quoted saying, “The sensation [of free will] is real, but the choice seems illusory. Laws of physics determine the future.” For Greene, our decisions are just outcomes of particle interactions, not independent acts of will.

Carroll is even more extreme in that he fully accepts many-worlds theory, so no decisions are made. Just world-splittings.

Sam Harris is more extreme than that. While Greene and Carroll accept an illusion of free will, Sam Harris denies that, and claims that he has no feeling of free will.

Do not take the Harris's too seriously. While they claim to rely on Physics, nothing they say depends on any physics. Instead it is largely based on their experiences taking psychodelic drugs.

A new paper carefully explains the error in thinking that modern science requires denying free will:

Reframing the Free Will Debate: The Universe is Not Deterministic
Henry D. Potter, George F.R. Ellis, Kevin J. Mitchell

Free will discourse is primarily centred around the thesis of determinism. Much of the literature takes determinism as its starting premise, assuming it true for the sake of discussion, and then proceeds to present arguments for why, if determinism is true, free will would be either possible or impossible. This is reflected in the theoretical terrain of the debate, with the primary distinction currently being between compatibilists and incompatibilists and not, as one might expect, between free will realists and skeptics. The aim of this paper is twofold. First, we argue that there is no reason to accept such a framing. We show that, on the basis of modern physics, there is no good evidence that physical determinism of any variety provides an accurate description of our universe and lots of evidence against such a view.

They are correct. If you think modern science requires determinism, then you are a couple of centuries out of date.

Of course the determinists, from Einstein to Greene, know all about quantum mechanics and its indeterminacy. But they act as if QM is just classical mechanics with some randomness added in, and say that no one could have agency over randomness, by definition. This misunderstands QM. The above paper addresses this argument, although they refer to forthcoming papers for details. It also address arguments from unitarity, time-reversal, block universe, and causal determinism.

Colleges have Big Jewish Fights

Columbia Mathematical physicist Peter Woit is ranting about campus politics:

I can’t stop myself from thinking about what happened in 1933 in Germany. If you don’t know this history, you really should read about it. The analogies with what’s going on now are remarkable.

He is not referring to the Columbia radicals who want to kill Jews, but the Trump administrations efforts to stop anti-semitism.

Scott Aaronson says:

Peter, your university’s antisemitism task force — formed with no Trump involvement — produced a harrowing report last year filled with specific incidents that added up to a pretty compelling case for Jewish and Israeli students (unless anti-Zionist) to want to steer clear of Columbia. If your position requires condemning all of your colleagues on that task force as liars, fanatics, and snitches, then that seems to me like an excellent way to lose this battle and alienate most of those who would otherwise be your allies. ...

If I’m unhinged and in need of psychiatric help, then so is the entire membership of Columbia’s antisemitism task force, as I’ve done nothing more extreme than try to balance my fear of Trump with my fear of what the task force concluded in its 120-page report.

Woit replies

The university has to somehow manage this, it’s a difficult problem. It’s being made a hundred times more difficult by people like Scott Aaronson who have no idea what’s going on here, but are so intent on joining the fight to destroy the other side that they will enthusiastically collaborate with the Fascists we’re trying to resist.

So Woit and Aaronson question the sanity of each other. Aaronson is a Jew married to an Israeli, and Woit is a gentile from Eastern Europe.

The core of the problem is that Columbia and Harvard have become havens for left-wing crazies:

Last year, Harvard earned the worst score ever recorded in FIRE’s College Free Speech Rankings: Zero. This year, the elite Ivy makes a repeat poor performance — and finds fresh company at the bottom, with NYU and Columbia joining the unenviable list of “abysmal” schools for free speech.

With scores ranging from zero to 100, NYU plummeted nearly 30 points this year, and Columbia fared even worse, becoming the second school after Harvard to ever receive a zero. And Columbia, like Harvard, actually received a negative score that we rounded up to zero. The only reason Columbia was spared from receiving the title of this year’s Worst College for Free Speech is that Harvard’s actual score was even worse, a full 21 points lower.

So Columbia and Harvard do not allow free speech for right-wingers, but they do allow faculty and students to side with the Oct. 7 Gaza/Hamas attack on Israel and with generally attacking Jews.

Another part of the problem is that federal spending is out of control, and Trump administration efforts to hold grant recipients accountable has brought howls of protest from universities.

Update: Dr. Bee comments on Woit, Aaronson, and others. She notes that many support what Trump is doing.

Facing Reality is an Ugly Scar

To see how foolish the many-worlds theory (MWI) is, just read what the advocates say.

Lev Vaidman just posted The many-worlds view of quantum mechanics:

My explanation has two very different parts.

i) The ontology, stuff that exists, including laws constraining possible states of stuff and dynamical laws of time evolution of stuff.

ii) The prescription of correspondence of the state of stuff with our experiences which we inquire through our sensory organs, sometimes equipped with instruments like telescopes, microscopes, sonars, etc.

The ontology is all the parallel universes. But relating the theory to our experiences in part (ii) is impossible without probability, and that is rejected, so he settles for a theory that does not relate to our experiences.

In conclusion, physics explains all phenomena we observe on Earth extremely well. Collapse of a quantum state at measurement is an ugly scar on a beautiful quantum mechanics. The only role of the collapse is to avoid parallel worlds which anyway are not supposed to be seen according to the theory. Without collapse we have to accept MWI. Apart from the disappointment in understanding that I am not a unique Lev Vaidman, and that there are multiple copies of me in other worlds, MWI allows me to believe that by and large I understand how the universe works. For me, parallel worlds are not a too high price to pay for understanding Nature.

So he says the collapse is just a way of avoiding the parallel worlds that we never see anyway. I call that facing reality, but he says it is an ugly scar.

He acts as if the collapse is peculiar to quantum mechanics, but it is not. All scientific theories do something similar when a prediction is compared to a measurement. The Bayesians call it adjusting their priors.

So what does he get from having of other worlds that cannot be seen? It allows him to believe that he understands Nature!

The many-worlders complain bitterly about the collapse being part of quantum theory, but it is very much part of many-worlds theory also. Instead of calling it collapse, they call it world-splitting. Instead of collapsing the wavefunction so that it better describes our universe, they say that the wavefunction decomposes into pieces where one piece describes our universe, and other pieces describe unobservable parallel universes.

The MWI does not solve the measurement problem, or explain the collapse/splitting, or do anything useful.

This is not Physics, and not science. It is too stupid for a rebuttal. There is not any substance to the theory. I would not even bother commenting on this nonsense, except that a great many of our leading physicists and physics expositors buy into it.

Broadly speaking, science consists of making observations, formulating theories, making prediction probabilities, and then making measurements to reconcile theory with experiment.

Many-worlds theory says to skip the last two steps. It denies that prediction probabilities make any sense, and it says that reconciling with experiment is an ugly scar that just rules out invisible parallel worlds. It is impossible to believe in many-worlds and have a scientific world view. For this reason, I doubt anything from Sean M. Carroll, Max Tegmark, and Leonard Susskind, even though they are all brilliant and explain some things very well.

Update: According to Tegmark, the term "ugly scar" is from Gottfried in 1989.

Using a Quantum Computer for Random Numbers

Prof. Scott Aaronson brags:

today JP Morgan Chase announced that, together with Quantinuum and DoE labs, they’ve experimentally demonstrated the protocol I proposed in 2018, and further developed in a STOC’2023 paper with Shih-Han Hung, for using current quantum supremacy experiments to generate certifiable random bits for use in cryptographic applications. See here for our paper in Nature—the JPMC team was gracious enough to include me and Shih-Han as coauthors.

Bloomberg reports:

JPMorgan Chase & Co. has generated and certified so-called truly random numbers using a quantum computer, in a world-first that the bank hopes will have applications for security and trading.

Researchers created the sequence using a quantum computer built by Honeywell’s Quantinuum, according to a paper published in the scientific journal Nature on Wednesday. JPMorgan researchers, alongside Argonne and Oak Ridge national laboratories and the University of Texas at Austin, then became the first to prove mathematically that they had produced “genuine randomness.”

Most so-called random number generators, which are important for encrypting sensitive data, aren’t actually random. They’re pre-determined sequences. Computers run on a set of programmed mathematical operations that will always return the same answer, raising the risk that hackers with access to increasingly sophisticated computing power could crack encryption codes.

Computers are not really deterministic. They have a CPU with a built-in hardware random number generator. Those numbers are as genuinely random as anything else. The advantage of Aaronson's method is that the numbers are certifiably random.

Aaronson admits that the method is not really practical, and it is hard to imagine a use for it. If you want to generate a private cryptographic key, there are much easier ways. Eg, you could record a video of yourself and hash it. You could use the CPU generator. You could use the generator that comes with password and bitcoin apps.

There are also public random number generators, such as here and here. It is a little tricky for multiple parties to agree on a fair lottery, but there are many ways that are a whole lot easier than using a quantum computer.

One way is to agree on a lottery for a particular day is to agree to has (with sha256, say) of the NY Times front page that day, or the stock market trades, or the baseball scores. A drawback is that if a lot of money were at stake, maybe someone would bribe a NY Times editor to drop a story or a baseball player to throw a game in order to influence the hash. Such attacks would be extremely improbable.

The Rise of Stochasticity in Physics

New paper:

The rise of stochasticity in physics
Hans A. Weidenmüller

In the last 175 years, the physical understanding of nature has seen a revolutionary change. Until about 1850, Newton's theory and the mechanical world view derived from it provided the dominant view of the physical world, later supplemented by Maxwell's theory of the electromagnetic field. That approach was entirely deterministic and free of probabilistic concepts. In contrast to that conceptual edifice, today many fields of physics are governed by probabilistic concepts. ...

The success of the theory led physicists to adopt what became known as the mechanical world view. According to that view, all physical processes can be understood on the basis of Newton’s equations. The theory is completely deterministic. There is no room whatsoever for probabilistic concepts which play a role only in the analysis of statistical and systematic errors. Such errors were considered epistemic and, therefore, did not challenge the validity of the mechanical world view. (A notable exception is the discovery of the dwarf planet Ceres in 1801. After its discovery, the planet was lost and could be retraced only with the help of Gauss’ statistical least-squares method).

That is a pretty big exception. The Newtonian mechanics seems deterministic, but in practice it is not. Like Gauss, you have to make imperfect observations, do some statistical estimations, and make a probabilistic prediction.

The whole field of AI used to be mostly deterministic, but now they follow the same stochastic pattern. They run on deterministic computers, and use lots of deterministic formulas, but the big AI models make very heave use of statistical estimates and probabilistic predictions.

I no longer agree with saying that classical mechanics is deterministic. All of science is inherently stochastic.

Historically, probability was developed after calculus. I thought that calculus would have been the conceptually more difficult subject.

Advocates of many-worlds theory reject probability. The theory does not make some worlds more likely than others, as some assume. I think that the followers must have some fundamental misunderstanding of what probability in math and science is all about.

Today, use of probability and statistics is pervasive in all of science. Every prediction is made with some probability, and every test is analyzed with statistics. So I do not think that there is any such thing as deterministic science. Classical physics is not, and neither is biology, chemistry, medicine, or anything else.

In summary, in the last 175 years physicists have been led or been forced to ascribe an ever increasing role to probability in the description of nature. I have listed four causes for that development: Loschmidt’s number supporting Maxwell’s theory, irreversibility leading to Boltzmann’s approach, Bequerel’s discovery, spectral lines and black-body radiation leading to quantum theory, and Poincare’s discovery of classical chaos. Random-matrix theory is different. It was not imposed on physicists by an experimental or theoretical discovery but was introduced to compensate for the incomplete knowledge of the Hamiltonian.

He is right about those trends, but probability would have become essential in all of science even without those four trends.

Investing in 150 Proof-of-concept Projects

More quantum computer hype in the business news:

A Practical Quantum Computer Is Coming! But When?

CNBC 3.85M subscribers

Google, IBM, Amazon, Microsoft and Intel are all working on quantum technology, as are numerous startups. At its annual GTC developer conference this week Nvidia CEO, Jensen Huang, announced the company was opening a quantum research lab in Boston. Governments around the world have also pledged over $50 billion to develop the technology. Quantum computers hold huge potential, with experts saying that they could transform entire sectors including material science, pharmaceutical research and financial services. But despite massive advancements in the field in recent years, right now, these quantum computers aren’t able to solve big real-world problems. CNBC's Kate Rooney visits California-based startup, PsiQuantum and spoke to experts about the major challenges this tech still faces as engineers work to transition quantum computers from lab experimentation to commercial viability.

As the video explains, many billions are being invested, in a huge fear of getting left behind. Much of it is going into "proof of concept" projects.

15:54 Public interest in quantum technology is growing. 15:57 The number of quantum computing proof of concept 16:00 enterprise projects surged by 50% between 2022 and 16:04 2024, to over 150 active projects. 16:08 Consulting firm Booz Allen, Airbus Ventures and Bosch 16:12 Ventures have all invested in quantum computers. 16:14 Meanwhile, Shadbolt says Illinois is investing $500 16:17 million to construct a quantum computing campus in 16:21 Chicago, of which Psi quantum will be the anchor 16:24 tenant. Psi quantum has also received $620 million from 16:29 the Australian and Queensland governments to 16:31 build a utility -scale quantum computer in 16:34 Brisbane, which the company says will be operational by 16:37 the end of 2027. 16:39 Experts say, investing now is a smart move. 16:43 When quantum computers reach quantum advantage, 16:46 which is effectively the period in which quantum 16:48 computers outperform classical computers at 16:52 important real world problems, 16:54 it will be much, much harder to get your 16:56 hands on a quantum computer unless you're developing 16:59 partnerships with the major providers right now.

Some people are going to see this, and think that quantum computing must really be a hot technology, to have so much investment, and even a panic to invest more.

I think the opposite. With generous funding to a lot of super-smart physicists of 150 proof-of-concept projects, and none proving that the concept is viable, I think that it is probably impossible.

The Nvidia CEO got some heat for saying quantum computing is many years away:

He also expressed surprise that his comments were able to move markets, and joked he didn’t know that certain quantum computing companies were publicly traded.

“How could a quantum computer company be public?” Huang said.

Forty years ago, a company had to be profitable to go public. Later, companies could go public with a large market share and user base, and no profits. Now a company can go public with no product, no customers, and not even a proof of concept.

Meanwhile, the England crypto spooks have published a roadmap for protecting communications from quantum computers:

In our 2023 white paper, the NCSC outlined the need to prepare for migration to post-quantum cryptography (PQC) due to the threat to cryptography posed by future developments in quantum computing.

The guidance defines three phases for migration.

The first of those involves carrying out a full discovery exercise to understand your estate, and identify services that are dependent on cryptography that will need to be upgraded to PQC. This then enables you to build an initial migration plan, identifying priority services for migration. 2028 is the target date for completing all of this.

The second phase is carrying out the highest priority migration activities that you have identified, and refining your plan as the PQC ecosystem develops so that you have a thorough roadmap for completing migration. You should aim to complete this phase in 2031.

The third phase is to complete migration to PQC of all your systems, services and products, with 2035 as your target.

That does not mean that they think SSL/TLS encryption will be broken in 2035. They like to preserve secrets for 50 years, so maybe they are worried about attacks in 2085.

Quanta magazine reports that quantum algorithms have been disappointing:

This contest almost always ends as a virtual tie: When researchers think they’ve devised a quantum algorithm that works faster or better than anything else, classical researchers usually come up with one that equals it. Just last week, a purported quantum speedup, published in the journal Science (opens a new tab), was met with immediate skepticism from two separate groups who showed how to perform similar calculations on classical machines.

Military intelligence will switch to PQC, but I would not be surprised if the private sector never switches.

D-Wave Claims Quantum Supremacy

Quantum computing stock market values are up again, as D-Wave got a paper published in AAAS Science, the top American science journal, claiming quantum supremacy. But SciAm reports:

Loud declarations of various types of quantum advantage aren’t new: Google notably made the first such claim in 2019, and IBM made another in 2023, for example. But these announcements and others were ultimately refuted by outside researchers who used clever classical computing techniques to achieve similar performance. In D-Wave’s case, some of the refutations came even before the Science paper’s publication, as other teams responded to a preliminary report of the work that appeared on the preprint server arXiv.org in March 2024. One preprint study, submitted to arXiv.org on March 7, demonstrated similar calculations using just two hours of processing time on an ordinary laptop. A second preprint study from a different team, submitted on March 11, showed how a calculation that D-Wave’s paper purported would require centuries of supercomputing time could be accomplished in just a few days with far less computational resources.

There is also a lot of skepticism about Microsoft's claim of a topological qubit.

Gil Kalai has not conceded, and has doubled down with his Quantum Computing Skepticism.

Let's review the arguments in favor of quantum supremacy. The most common one is that qubits can be 0 and 1 at the same time, just as Schrodinger's Cat can be alive and dead simultaneously. Operations on qubit are thus able to examine an exponential number of possibilities at the same time, leading to an exponential speedup in computation.

Scott Aaronson says that this is wrong, because it misleadingly predicts an exponential speedup where none is possible. Instead he says the speedup comes from negative probabilities.

The QM probabilities are never negative. That is just his way of making destructive wave interference sound mysterious. When you say a computational speedup comes from wave interference, it is harder to understand.

Aaronson falls back on the argument that it is up to the skeptic to prove that quantum computers are impossible, and that would be very interesting, but no one has done that.

The many-worlds folks say that the speedup comes from computation being done in parallel universes. Most people say that there is no way to observe those parallel universes, but we are supposed to believe that they speed up computations somehow.

Feynman's original argumen was that simulating QM can be exponentially slow, so it can be faster by running a quantum experiment. You can do a chemical reaction faster than you can simulate it from first QM principles. Okay, that is true, but it is a big leap to using QM to factor large integers.

Finally, there is the argument that quantum researchers have made so much progress already. Yes, but maybe it is like slimbing trees to make progress towards going to the Moon. There is progress, but the goals seem as far away as ever. Nobody has a convincing experiment showing that quantum computing is possible.

The Aether is not a Rest Frame

Physicist Sean M. Carroll says, in his latest AMA that quantum field theory has no aether because the whole point of the aether is to have a rest frame for measuring motion:

Marson chady or chatty says 50:03 when I was in high school we were told that the 19th century scientists were looking for a medium which they called 50:08 ether in which light waves would propagate eventually the theory of electromagnetism established that there 50:14 was no such medium yet I can't help but think that the original view was Vindicated by Quantum field Theory isn't 50:20 the electron field of quantum field Theory the equivalent of ether uh no it 50:25 is not the equivalent of E I have answered this question or talked about it in various times but it's been a while so let's address it again um the 50:34 fields of quantum field Theory are just the quantum versions of the fields of classical field Theory so if you think 50:41 that classical electromagnetism which is a classical field Theory uh doesn't need 50:47 ether then you don't you think that Quantum Fields don't need ether either the point is that ether was supposed to 50:53 be like you say A medium in which waves propag at whereas in contrast field 50:59 Theory uh classical or Quantum takes the fields as the fundamental independent 51:05 entities uh the waving electron field or the waving electromagnetic field or the 51:10 waving higs field or whatever none of these are waves in something other than themselves okay so that's the 51:17 ontological difference and there's also a practical difference the whole point of The Ether in 19th century physics was 51:24 to allow for there to be a rest frame with respect to which you can measure your motion uh as opposed to the naive 51:31 reading of Maxwell's equations which say there is no uh Universal rest frame so 19th century physicists went to Great 51:37 Lengths to sort of bend over backwards and figure out how you could reconcile the existence of a rest frame determined 51:44 by The Ether with the fact that you couldn't observe it in any way in Maxwell's equations and that's how they 51:49 invented things like Lorent Transformations even before relativity came on the scene but in Quantum field 51:55 Theory there's no rest frame there's no rest frame everything is perfectly relativistically invariant so the whole 52:01 point of the ether is completely missing in Quantum field Theory so I don't think that's an especially useful way of 52:07 thinking about things

No, I don't think that anyone thought that was the point of aether. For my sources, see the essays on aether in the Encyclopedia Britannica by Maxwell (9th ed, 1878) and Larmor (11th ed, 1911). See also Einstein's views on the aether. None of these say that the aether gives a rest frame.

Maxwell wrote:

The hypothesis of an aether has been maintained by different speculators for very different reasons. To those who maintained the existence of a plenum as a philosophical principle, nature's abhorrence of a vacuum was a sufficient reason for imagining an all-surrounding aether, even though every other argument should be against it. ...

But besides these high metaphysical necessities for a medium, there were more mundane uses to be fulfilled by aethers. Aethers were invented for the planets to swim in, ...

The only aether which has survived is that which was invented by Huygens to explain the propagation of light. The evidence for the existence of the luminiferous aether has accumulated as additional phenomena of light and other radiations have been discovered; ...

Whatever difficulties we may have in forming a consistent idea of the constitution of the aether, there can be no doubt that the interplanetary and interstellar spaces are not empty, but are occupied by a material substance or body, which is certainly the largest, and probably the most uniform body of which we have any knowledge.

In quantum field theory, the vacuum is not empty, and could be regarded as a medium for the propagation of light, and for electrons and everything else.

The story is often told that Einstein invented relativity in order to disprove the aether, show that there can be no rest frame. This story is false, as Einstein did not invent relativity, and what he said about the aether was essentially the same as what Lorentz wrote ten years earlier. The theory of relativity does not say whether there can be a rest frame.

I wonder why people keep telling this silly story. My guess is that people like to believe that the aether was some sort of superstitious belief of lesser men, and that rejecting it was a great intellectual accomplishment, along with rejecting God, the monarchy, and geocentrism.

Carroll is also asked to speculate about the development of general relativity:

nichel Kramer says if Einstein had 2:00:51 not veloped general relativity when he did how soon would it have been developed well we don't know um I don't 2:00:57 think it would have taken that long like it wouldn't have taken 50 or 100 years we already had all the tools right we 2:01:03 had riemanian geometry we had special relativity it's possible for example 2:01:08 that minkowski or minkovsky to be a little bit more correct would have developed it Herman minkovski of course 2:01:14 um was the first to promote the idea of thinking about relativity in terms of SpaceTime and he was a mathematician he 2:01:21 had actually taught Einstein uh so it was 1907 2 years after Einstein's special relativity papers that minkovsky 2:01:27 first said we should think about it in terms of SpaceTime um Einstein eventually settled on general relativity 2:01:33 in 1915 but minkovski passed away in 1909 so he didn't really get a chance to 2:01:39 follow up on his Insight that we should think about things in terms of SpaceTime maybe he would have come up with it but 2:01:45 you know it's an interesting fact about the progress of physics that the progress of physics on theoretical 2:01:51 physics is usually led by physicists not by mathematicians with overwhelming um 2:01:57 probability not that it's impossible to imagine mathematicians doing it but when we think back to how general relativity 2:02:04 came about and there were you know real mathematical issues there and a lot of important steps were taken by 2:02:11 mathematicians benovsky is one David Hilbert of course is another but still it was a physicist it was Albert 2:02:16 Einstein who actually put it together because that physics insight about 2:02:22 the principle of equivalence and how gravity works and things like that that's the bread and butter of physicists not mathematicians the 2:02:29 question is was there any other physicist who would have thought the same way as Einstein there were certainly physicists who had the same 2:02:36 mathematical chops that Einstein did but the physical Insight that he had was unmatched since Galileo basically uh and 2:02:43 has still been unmatched since so it might have taken a while but the tools were there so I don't think it would have taken too 2:02:49 long

I agree that physicists are better at physical insight than mathematicians, but his examples are distorted.

Poincare, Minkowski, Grossmann, and Hilbert were all primarily mathematicians, and they were the chief originators of relativity theory, after Lorentz. Poincare published the first relativistic theory of gravity. Poincare and Minkowski both died before general relativity. Einstein's first general relativity version was a joint work with Grossmann, and his second was a joint work with Hilbert. Einstein also worked with mathematicians Levi-Civita and Ricci.

Carroll says that Minkowski's 1907 spacetime was two years after Einstein, but it is doubtful that Einstein's work was any influence at all. Minkowski's spacetime was based on Poincare's spacetime.

String Theory and the Black Hole War

Leonard Susskind gives a two-hour interview.

He is a smart and distinguished physicist, but he has some silly views. He brags about winning the Black Hole War, but he did not. In a recent survey, only 27% agreed with him that information falling into a black hole is preserved in Hawking radiation. Only 11% agreed with many-worlds theory, which he has favored in the past. Not sure if he still does.

The survey had some other curious opinions, such as whether matter falling into a black hole gets crushed into a singularity (29% say yes) and whether the big bang started time with a singularity (only 11% say yes). While you might have heard that the Copenhagen Interpretation is dead, only a minority subscribed to some non-Copenhagen interpretation of quantum mechanics. The survey was given in Copenhagen, so maybe the home team had an advantage.

Information has no physical definition, and has no good reason to be conserved. Susskind would only say that it is conserved because quantum field theory is unitary. That is the same reason he gives for many-worlds. So wouldn't that mean that information could leak into parallel universes, not to be seen again?

He pushes a lot of other wacky ideas, such as anti-desitter space, black hole event horizon firewalls, string theory landscape, entangled wormholes, etc. It is all nonsense. All of it is theoretically dubious, and impossible to observe. Viewers must get a kooky view of Physics when the leading popularizers say such bizarre and unscientific things.

Boycott Math to Save Greenland

American professors have been whining about possible Trump administration budget cuts, as if this is the end of scientific research. Now Peter Woit wants to boycott the scheduled 2026 Philadelphia meeting of the International Congress of Mathematicians!

The 2022 meeting in St. Petersburg Russia was canceled, because of pro-Ukraine political activists. This was unfortunate. It only punished Russian mathematicians and conference organizers who had nothing to do with Ukraine politics. Russia was not using these conferences for political gain. Only the supposedly free westerners were.

American and European scientific organizations are sometimes more politicized than Russian ones under Stalin.

Woit is from Latvia, so maybe he hates Russia. But does he also hate Philadelphia? He laments that it may be hard to find a host country that meets his ideological purity test, as he says the world is going fascist.

John Baez chimes in that he moved to Scotland to escape Trump!

Here is the only sensible comment:

Alessandro+Strumia says:
February 26, 2025 at 2:08 am

I could attend the ICBS conference in China because it says «This conference is a purely academic event. It does not promote any political opinion». I cannot attend conferences at Perimeter, not even on zoom, because it forces to accept a Code of Conduct that contains political elements including DEI (“inclusivity, equity, diversity”) and I am not Marxist. Removing all these woke Codes of Conduct that did not exist a decade ago seems to me a better contribution to freedom than avoiding conferences in the US.

Yes, it is embarrassing that Russia and China can keep politics out of scientific conferences, but the USA and Europe cannot.

Scott Aaronson also has Trump derangement:

Trump and Vance’s total capitulation to Vladimir Putin, their berating of Zelensky in the Oval Office for having the temerity to want the free world to guarantee Ukraine’s security, as the entire world watched the sad spectacle. ...

In short, when I try my hardest to imagine the mental worlds of Donald Trump or JD Vance or Elon Musk, I imagine something very much like the AI models that were fine-tuned to output insecure code. ... It’s as though, by pushing extremely hard on a single issue (birtherism? gender transition for minors?), someone inadvertently flipped the signs of these men’s good vs. evil vectors.

He makes an analogy to AI LLM models that turn evil.

He is a smart man, but it is hard to believe that he really does not understand the USA's reluctance to guarantee Ukraine's security.

Russia and Ukraine are minor corrupt countries on the other side of the world with an ugly border dispute. It probably would have been resolved peacefully, except that the USA and Zelensky keep threatening to put NATO weapons on Russia's border. Russia says that it is defending itself from NATO expansion. Maybe Putin is lying, but USA involvement is making things worse, and it is time to pull out.

Maybe you disagree, and that's fine, but how it is that Aaronson cannot even see the logic behind Trump's position?

Professor Dave Blasts Dr. Bee Again

Professor Dave has a popular Youtube channel, with twice the subscribers of Dr. Bee. He posts a lot of good videos explaining textbook material, and sometimes debunks charlatans and quacks. I mentioned his attacks before.

Now he says she is a grifter for cash in a 1.5 hour rant:

Sabine Hossenfelder Can’t Stop Acting Like a Complete Fraud

Professor Dave Explains
3.64M subscribers

I've already made two videos about Sabine Hossenfelder's gradual decline into deception and charlatanry, but her behavior has gotten so bad lately that it's time to make another one. This time, after examining her latest pathetic stunt, it's time to bring in some physicists to comment on the ridiculous things she's been spewing. Those would be Eluned Smith, Aram Harrow, and Tracy Slatyer, all professors of physics at MIT. Most of you were already on board, but if you Sabine fanboys wouldn't listen to me before, maybe you'll listen to them.

He says a lot of her videos are okay, but she has drifted down the right-wing rabbit hole. He ends up calling her a nazi.

He interviews physics professors to explain that Physics really has been making big progress, and that he public taxpayers have benefited so greatly that they should happily fund further research.

Listen for yourself, and tell me whether you are convinced. One said that supersymmetry might have explained a few things, but those explanations have been ruled out by the LHC collider. That was progress. I agree that was progress, but I did not see any benefit to the taxpayers.

I think she is correct that most of the funded research is of no tangible value. The video guests do not directly rebut her, but instead ramble about how research often has value.

Strangely, they never address superdeterminism. Of all her videos, that is the subject where she has the greatest expertise, and it is also the one with her kookiest views. Superdeterminism is so kooky that it is reasonable to reject everything she has to say, if she believes in it. But that is not what he does.

It is true that high-energy theoretical physics has stagnated for about 50 years. We have had 50 years of 1000s of papers on new theories and models, and they have nearly all failed. The last big advance was the standard model. String theory, supersymmetry, grand unified theories, and many others have gone nowhere. Everyone thought that the LHC would discover new physics, but it did not.

He gives the argument that the electron was discovered as pure scientific research, and it had big commercial payoffs decades later. So maybe the Higgs boson will similarly have commercial payoffs someday. That is just silly. The Higgs is not going to have any commerical utility. It cost $10 billion jus to make one at the LHC accelerator.

Update: Dr. Quantum Supremacy piles on

Sabine #17: I very often agree with your acerbic takes, or at least enjoy them. Not always. To me, superdeterminism is a candidate for the most insane idea in the history of physics — certainly 1000x more insane than anything the string theorists have ever come up with. But even your superdeterminism advocacy wouldn’t merit a comparison to RFK Jr.

No, what merits the comparison to RFK Jr. is this recent video of yours. There, with comically unconvincing caveats (“I’m not necessarily saying this should happen, just that it will“), you speak approvingly about the imminent destruction of publicly-funded academic science, in favor of just letting Musk, Bezos, et al. fund whatever they feel like.

Yes, superdeterminism is insane, but so is many-worlds, and Aaronson endorsed it in 2021. So they are all promoting fringe and insane versions of quantion mechanics.

Aaronson is mainly upset that Hossenfelder predicts an end to taxpayer funding of whatever academics want to study, especially fringe ideas with no real world relevance. She compares academic research to Communism, where central government committees decide what to fund, and make political decisions with little public accoutability.

He praises this comment:

For instance, there’s a whole genre of articles claiming that some experiment has shown that quantum processes can rewrite the past, foresee the future, or take a negative amount of time. The AMO physicists hopefully all know the real story is “our experiment checked that textbook QM works exactly as expected, but if QM _wasn’t_ true you’d need some crazy retrocausality to get the same results”, but they choose not to communicate that subtlety. It seems to be a game they play to get into top journals. But then the public just gets more confused, and convinced that physicists don’t know what’s going on.

Yes, you could say the same about arguments for superdeterminism, many-worlds, or Bohmian mechanics. Those arguments all depend on QM not being true, but that subtlety get omitted. Most quantum weirdness arguments work that way. For example, Bell proved that if QM were false, and were a some sort of classical theory instead, then it would have nonlocal properties.

Update: He goes on to explain:

The basic problem here is that Bell’s Theorem is a theorem. And it shows that you can’t have a secretly classical theory that

(1) reproduces the prediction of QM for two entangled particles and

(2) is free of “fine-tuning” — i.e., a conspiracy of initial conditions sufficient to force random number generators to produce particular outputs, human brains to make particular choices, etc., in order to cause the entangled particles to be measured in certain bases and not others.

Furthermore, over the decades, the “Bell deniers” (superdeterminists and others) have shown that they’re willing to generate an unlimited amount of verbiage, and even “math,” in an attempt to evade these simple points—thereby wasting unlimited amounts of everyone else’s time, in a sort of intellectual denial-of-service attack.

A response says: "I’ll let you determine the best use of your own time". Ha, ha.

Aaronson is correct, but seems to miss the point. Hossenfelder is not a Bell denier, but arguing for option (2). That is, reality is a secretly classical theory with a fine-tuned conspiracy to fool us into all our experiments being wrong.

Philosopher Promotes Determinism

I mentioned Dr. Bee promoting superdeteriminism, and philospher Stephen Maitzen also promotes determinism.

Here is his core argument:

You decided to read this post. Suppose your decision wasn’t necessitated by the prior conditions: you might have decided not to read this post despite everything being exactly as it was. If we delve into the question “Why did you decide to read this post rather than not ‒ what made the difference?”, at some stage in our ever-deeper inquiry the answer is nothing. That seems to me a perfect example of magic: there was a difference (you decided one way rather than another), but literally nothing made the difference.

If you reject magical thinking, then you ought to accept determinism.

In other words, he just declares non-determinism to be magic.

Einstein believed in determinism, but most physicists do not. Certainly nothing in textbook physics requires determinism, and many believe it is incompatible with quantum mechanics. But Maitzen argues:

Contrary to what you may have heard, determinism does not conflict with current physics. ...

One such deterministic theory is Bohmian mechanics, named for the physicist David Bohm. ...

Misinformed people say that the experimental violations of Bell’s Theorem rule out deterministic physics. Bell himself knew better: what they rule out is physics that’s both deterministic and local. Bohmian mechanics survives because it’s nonlocal, but (as Bell showed) so is quantum mechanics itself.

No, this is misinformed. Nearly all physicists reject Bohmian mechanics because it is nonlocal, and I would call it magic.

Quantum mechanics is local as far as we know. Quantum field theory is local.

Some people interpret Bell's inequality as saying quantum mechanics must be indeterministic. That appears to be the case, but there is always the possibility of some underlying deterministic theory.

Any indeterministic theory could have an underlying deterministic theory.

There is no hope of science proving determinism, so why would anyone believe in it? If you accept determinism, then you are just a cog in a machine, with no free will or any purpose to life. People make choices all the time, and it is almost impossible to live life as if all those choices are determined. I doubt that anyone can do it, except maybe for babies, comatose patients, and schizophrenics.

Dr. Bee Pushes Superdeterminism Again

I have defended Dr. Bee, as she often gives nice summaries of science outside her expertise. But not when she gets Physics in her own expertise wrong. She explains:

7:20 And then let me finally say some words about how superdeterminism 7:24 explains the quantum mechanical result. Superdeterminism is an unfortunate 7:29 term that John Bell used to describe what he thought was an implausible explanation. What 7:36 it really means is just that the probability of a measurement outcome depends on what you 7:41 measure. In the GHZ table this means that for example the result for the side of the second 7:48 coin in the third measurement can differ from the one in the first measurement, 7:53 because the measurements on the other coins are different. The result depends on the context. 7:59 The benefit of superdeterminism, and the reason why I am convinced it’s the correct explanation, 8:06 is that it is local and therefore compatible with Einstein’s theory. Superdeterminism has 8:13 no “spooky action at a distance.” Indeed, we know from Bell’s theorem that it’s 8:18 the *only way to make the results of quantum mechanics compatible with Einstein’s locality. 8:25 People don’t like this explanation because they think it’s constraining 8:29 their free will or something. But the way that I think about it is just that it’s 8:35 a consistency requirement. And yes I am working on a few more papers about this,

She is writing wrong papers. In quantum mechanics, the measurement outcome depends on what you measure. That has been accepted wisdom for a century. It is not superdeterminism, which nearly everyone rejects as not only implausible, but crazy.

Bell's theorem says that superdeterminism is the only way to make a local hidden variable theory compatible with known Physics. But again, mainstream physicists and textbooks have rejected hidden variable theories for a century.

Textbook quantum field theory is local, and compatible with relativity.

People do not like superdeterminism not just because it eliminates free will, but that it any possibility of doing a scientific experiment. It is part of The Existential Crisis Iceberg. If you accept it, there is no returning to rational thought.

Microsoft Claims a Topological Qubit

Microsoft brags in a new video:

Hear from the Microsoft team behind the recent breakthrough in physics and quantum computing demonstrated by the new Majorana 1 chip, engineered from an entirely new material that has the potential to scale to millions of qubits on a single chip.

Bloomberg piles on:

So it's an accelerator and it's very 13:52 complementary that some investors would say that this 13:55 artificial intelligence hype cycle has produced more hype than actual reality, 14:01 at least at the stage that we are Now. Is quantum computing going to be 14:04 different or follow a similar pattern?

Quantum computing is 1000x more over-hyped than AI. AI has already produced beyond what the hype was promising. Quantum computing has not delivered anything of use.

Dr. Quantum Computing notes:

Commenters point out to me that buried in Nature‘s review materials is the following striking passage: “The editorial team wishes to point out that the results in this manuscript do not represent evidence for the presence of Majorana zero modes in the reported devices. The work is published for introducing a device architecture that might enable fusion experiments using future Majorana zero modes.” So, the situation is that Microsoft is unambiguously claiming to have created a topological qubit, and they just published a relevant paper in Nature, but their claim to have created a topological qubit has not yet been accepted by Nature‘s peer review. ...

Q5. Didn’t Microsoft claim the experimental creation of Majorana zero modes — a building block of topological qubits—back in 2018, and didn’t they then need to retract their claim?

A. Yep. Certainly that history is making some experts cautious about the new claim. When I asked Chetan Nayak how confident I should be, his response was basically “look, we now have a topological qubit that’s behaving fully as a qubit; how much more do people want?”

Q6. Is this a big deal?

A. If the claim stands, I’d say it would be a scientific milestone for the field of topological quantum computing and physics beyond.

Yes, very interesting, if the claim stands.

Update: Dr. Bee adds her opinion.

Update: The WSJ published some skepticism about Microsoft's claims, which go beyond what has been published.

Many-Worlds Leaves Basic Questions Unresolved

Many-worlds theory is nonsense from beginning to end. Here is an illustration.

Here is a new paper, from China:

oes the Universe Split Everywhere at Once? Rethinking Branching and Nonlocality in the Many-Worlds Interpretation of Quantum Mechanics

The many-worlds interpretation (MWI) of quantum mechanics, first pro- posed by Hugh Everett III in 1957, offers a radical solution to the measure- ment problem by positing that all possible outcomes of a quantum measure- ment occur in different worlds (Everett, 1957; Vaidman, 2021).

No, it does nothing to solve the measurement problem.

In quantum mechanics, the measurement problem is the problem of definite outcomes: quantum systems have superpositions but quantum measurements only give one definite result.[1][2]

The supposed solution is to say that all the other possibilities happen in unseen parallel worlds. But that does nothing to explain why we only see one definite result in our world.

While this interpretation avoids the need for wavefunction collapse, it introduces the contentious concept of branching — a process where the universe splits into multiple worlds whenever a quantum event occurs.

No, the wavefunction still collapses in our world. The rest of the wavefunction becomes inaccessible in our world, and related to only other worlds.

Over the past decades, the modern formulation of MWI has refined this idea, grounding branching in environmental-induced decoherence, a process that explains the emer- gence of stable, quasi-classical worlds (Wallace, 2012). However, critical questions remain unresolved: Is branching global, happening throughout the entire universe instantaneously (Sebens and Carroll, 2018; Ney, 2024), or is it local, propagating at finite speeds? (Wallace, 2012; McQueen and Vaid- man, 2019) How does nonlocality in entangled systems influence branching? Most importantly, can MWI reconcile its branching mechanism with the principles of special relativity?

With those questions unresolved, nothing is resolved. The theory has no substance.

It is amazing that trained physicists can promote this nonsense. And they complain that Pres. Trump might cut funding for it.

This paper draws its own goofy conclusions.

This paper aims to resolve key tensions by demonstrating that branching is neither strictly global nor purely local, but nonlocal for entangled systems. ... Crucially, this non- locality is apparent rather than fundamental. The multiverse as a whole retains a Lorentz-invariant structure, with no preferred Lorentz frame or superluminal influence across all worlds. This reconciles MWI with special relativity while preserving its capacity to explain quantum nonlocality.

Many-worlds is an esoteric subject, but even if you know nothing about it, it should be clear that physicists have been writing about it since 1957, and they have gotten nowhere. Nobody knows what the theory means, on any level. There is no agreement on anything. And no way to test the theory. It is nothing but an undefined fantasy.

In 1957, Everett said that if the whole universe is described by QM, then there should be a wavefunction for the universe. In particular, an observer would be included. So when an observer sees one outcome out of several possibilities, and it seems like a collapse of some local wavefunction, then presumably there is some way to interpret that collapse in the wavefunction of the universe. All that is clear enough. The weird part is making the leap to saying that the collapse is the creation of parallel universes.

Update: New video on The Huge Flaw in the Many Worlds Interpretation. It explains how hard it is to make sense out of MWI. In particular, it explains that there is no way to make sense out of probability. To believe in MWI is to reject probability as a meaningful concept. The full podcast is here. But ignore the part from 1:10:00 to 1:14:00, where he claims that everybody had gotten Bell's Theorem wrong for 60 years, including the Nobel Prize committee a couple of years ago. No, the Nobel folks did not get it wrong.

Quantum Encryption Uses Light and Color

Here is some typical quantum encryption hype:

The future of internet security faces a major challenge: quantum computers could eventually break even the strongest encryption used today, making sensitive data vulnerable. To counter this threat, researchers worldwide are working on quantum networks — systems that leverage the principles of quantum mechanics to enable ultra-secure communication.

When fully developed and globally interconnected, these networks will form the quantum internet, providing encryption that cannot be intercepted or decoded.

No, quantum computers do not threaten the strongest encryption used today. They might threaten RSA, in about 50 years. Even then, I doubt it.

Regardless, no one is going to make secure networks out of this quantum encryption. They suffer a number of defects. They are slow and expensive. They cannot use routers. They are subject to hardware attacks. They cannot be authenticated. They depend on a probability of detecting an attack. They have to shut down if there is an attack.

Many-Worlds does not avoid Spookiness

Lev Vaidman writes a new paper:

It is argued that, keeping the standard paradigm of a scientific theory, the only way to avoid (spooky) action at a distance of quantum mechanics is to accept the existence of parallel worlds created at every quantum measurement. Einsten's boxes and Greenberger-Horne-Zeilinger scenario are analyzed in the framework of the many-worlds interpretation, Bohmian mechanics, and Ghirardi-Rimini-Weber collapse theory.

Here is his argument. Say you have two boxes, A and B, and you put a particle randomly in one of them. Then you separate the boxes, and open box A, seeing whether the particle is in it. Then you immediate know whether the particle is in box B.

He says this is spooky because the knowledge seems to leap from box A to B.

Now you repeat the drill, but instead of just moving the boxes, you split the universe into two universes. One universe has the particle in box A only, and the other has it in box B only. THe new universes cannot communicate or interact in any way.

Now it is still the case that finding the particle in box A tells you immeediately that it is not in box B, but only in that universe, so it is not spooky.

This is so stupid that I do not know how anyone can believe such nonsense. Saying that the universe splits does nothing to solve spookiness, or anything else.

Top Ten Physics Myths

Other sites go after astrology and other pseudosciences. I go after bizarre beliefs held by respected physicists.

1. Matter is mostly empty space.
This is based on the idea that matter is made of quarks and electrons, and those are point particles, leaving a lot of space in between. But matter is made of fields, and fields take up space. Especially fermionic fields.
2. Bell proved that Quantum Mechanics is nonlocal.
He only proved that QM could not be replaced by a theory of local hidden variables. The key point is that hidden variable theories do not work.
3. The universe is deterministic.
Some say that a scientific outlook requires that the past determines the future. On the contrary, many things appear fundamentally unpredictable.
4. Einstein invented relativity.
The theory, as we know it, was developed by Lorentz, Poincare, and Minkowski. They were years ahead of Einstein in every detail.
5. Information is conserved.
No, information is nothing like conserved quantities like energy and momentum. Conservation laws come from symmetry princples, and there isn't one for information. If you burn a book, the information is gone.
6. Quantum entanglement is a resource.
Entanglement can be puzzling, but the idea that it is a resource that can be brought to do useful things, like cryptography, teleportation, and computation is yet to be proved.
7. String theory generalizes the standard model and gravity.
This is just wishful thinking. It has not found any relation to the real world.
8. Many-worlds is the minimalist QM interpretation.
It is not even an interpretation. It takes QM, with its useful predictions, and replaces it with a theory that eliminates the predictions and says that anything is possible.
9. The universe has infinities and singularities.
Mathematical models often have singularities at the center of black holes, and at the beginning of the Big Bang. Also, quantum fields have infinities before they have been renormalized. None of these are observed. And the idea that there are infinitely many copies of yourself floating around the universe is just fanciful nonsense.
10. The quantum world is discrete.
Bohr said there is no quantum world. QM uses continous variables. It only appears discrete when you take measurements, as we observe eigenvalues and they are sometimes discrete.

What did I miss? I am sure there are many others.

Krauss Explains Extra Dimensions

Lawrence Krauss is one of the best public expositors of Physics, but I was disappointed by this interview.

3:29 and it was Einstein's genius to realize 3:31 well they're both right. Maxwell's right 3:34 and Galileo's right. what can what gives 3:37 here and he said well maybe it's the way 3:40 we measure space and time. maybe space 3:43 and time are personal things and they 3:45 depend upon your motion and in order to 3:48 get a measurement so each person's space 3:50 is in some and time in some sense unique 3:52 to them and that was the The Genesis of 3:55 special relativity

No, that was not the genesis of special relativity. That describes what Lorentz published in 1895, and Einstein's paper was not until 1905. Lorentz used Maxwell's equations to show how space and time can change to make observations independent of velocity of the frame, such as with the Michelson-Morley experiment.

Perhaps Krauss would object that Lorentz did not say that the theory is about the way we measure space and time. But Einstein did not either. That was done by Poincare and Minkowski.

there's an 4:21 absolute in the sense that that if you 4:24 think of the world as 4:26 four-dimensional time being an extra 4:28 dimension 4:30 then when I'm moving with respect to you 4:32 what I'm really kind of doing is 4:34 rotating in this four-dimensional space 4:36 so my space is your time and your time 4:38 is my space a little bit and when those 4:40 get mixed up you explain the wonderful 4:43 results of Einstein and so we now say 4:46 that we live in a four-dimensional 4:47 melski space

That idea was Poincare's in 1905, and built on by Minkowski in 1907. Einstein did not have anything to do with it.

If instead of living in 6:34 a four-dimensional world we live in a 6:35 five-dimensional world and somehow 6:37 electromagnetism is related to the 6:38 curvature of that extra Dimension that 6:40 you can't perceive well two people uh 6:44 kuta a mathematician and Klein a 6:46 physicist independently in in 1919 to 6:50 1926 came up with the same idea and 6:52 showed that this idea actually worked 6:54 mathematically if you assumed we live in 6:57 a five-dimensional universe and this 6:58 extra Dimension was invisible I and in 7:00 fact curled up on a very small 7:02 scale it was Klein who wanted it curved 7:04 up in a very small scale by the way and 7:07 I don't know if you can figure out why 7:08 kuta didn't didn't care he was a 7:10 mathematician why did he care the clein 7:12 wanted to say if there's an extra 7:13 Dimension if you don't see it there has 7:15 to be a reason and if it's curled up on 7:17 a very small scale then you can't 7:18 measure it in in in in experiments and 7:20 we can talk about that but in any case 7:22 if there was that extra Dimension and 7:24 and you could discuss a curvature in 7:26 that extra Dimension that you couldn't 7:28 directly see it's Remnant in the 7:30 four-dimensional its projection on the 7:32 four-dimensional universe that we can 7:33 see would give the equations of 7:35 electromagnetism it was an remarkable 7:38 idea turned out to be wrong because it 7:41 it also gave a little change to gravity 7:43 which we don't see and it got left aside

It was only wrong because Kaluza and Klein botched it up. Hermann Weyl was ahead of them with a similar idea in 1918, and that idea was essentially the modern gauge theory of electromagnetism. It can be viewed as a fifth dimension of spacetime, and it is not wrong.

He then rambles about string thoery having 22 extra dimensions. That theory really is wrong, or as Peter Woit would say, not even wrong.

You could say that the Standard Model has a group structure U(1)xSU(2)xSU(3) with 12 extra dimensions. We do not see them as spatial dimensions, as they have symmetries such that we only see the curvature effects. In that sense, we do have extra dimensions that are mostly hidden because of symmetries.

Here is Krauss giving a similar explanation of extra dimensions. He describes the extra dimensions as something that theorists have liked since 1919, but which have always failed. Maybe new accelerator experiments will detect extra dimensions.

It baffles me that he can say all this without mentioning that our very best modern Physics theory, the Standard Model, is a theory of extra dimensions. He talks about extra dimensions that are too small or too big or obscured for some other reason. In the Standard Model, the extra dimensions are obscured by gauge symmetries.

A Century of Quantum Mechanics

Physicist Sean M. Carroll writes a high-profile Nature essay:

Why even physicists still don’t understand quantum theory 100 years on

Quantum mechanics depicts a counter-intuitive reality in which the act of observation influences what is observed — and few can agree on what that means.

He did not write those titles. He does not deliver on the titled promises.

PHysicists understand quantum mechanics just fine, and there is broad agreement on what it means. There is a faction of philosopher wannabes like him who believe in many-worlds or some other goofy variant, but the real work is being done by those who follow Copenhagen or say shut up and calculate.

Most of what he writes is reasonable:

It was the German physicist Werner Heisenberg who, in 1925, first put forward a comprehensive version of quantum mechanics. ... So it is fair to celebrate 2025 as the true centenary of quantum theory. ...

Whereas in classical physics, a particle such as an electron has a real, objective position and momentum at any given moment, in quantum mechanics, those quantities don’t, in general, ‘exist’ in any objective way before that measurement. Position and momentum are things that can be observed, but they are not pre-existing facts. That is quite a distinction. The most vivid implication of this situation is Heisenberg’s uncertainty principle, introduced in 1927, which says that there is no state an electron can be in for which we can perfectly predict both its position and its momentum ahead of time2.

This is because position and momentum are non-commuting operators.

He starts to go off the rails:

As a result, the probability of observing one particle to be somewhere can depend on where we observe another particle to be, and this remains true no matter how far apart they are.

Actually, classical probabilities work the same way. Probabilities nearly always depend on other observations.

Bohr, along with Heisenberg, was willing to forgo any talk about what was ‘really happening’, focusing instead on making predictions for what will happen when something is measured.

The bizarre logic of the many-worlds theory

The latter perspective gave rise to ‘epistemic’ interpretations of quantum theory. The views of Bohr and Heisenberg came to be known as the Copenhagen interpretation, which is very close to what physicists teach in textbooks today.

Yes, that is the mainstream view. Science is all about what can be observed, not speculations about imaginary parallel universes.

Mercifully, the paywall blocked me from reading the rest, which presumably rambles into many-worlds nonsense. I can only get the above link to a 2019 essay:

At the beginning of Something Deeply Hidden, Sean Carroll cites the tale of the fox and the grapes from Aesop’s Fables. A hungry fox tries to reach a bunch of grapes dangling from a vine. Finding them beyond his grasp, but refusing to admit failure, the fox declares the grapes to be inedible and turns away. That, Carroll declares, encapsulates how physicists treat the wacky implications of quantum mechanics.

Carroll wants that to stop. The fox can reach the grapes, he argues, with the many-worlds theory.

That is where we get the term "sour grapes". In this case, the many-worlds theory really is inedible. Carroll is misleading everyone.

Update: Nature magazine also has an essay on Two-Eyed Seeing:

This Perspective focuses on the integration of traditional Indigenous views with biomedical approaches to research and care for brain and mental health, and both the breadth of knowledge and intellectual humility that can result when the two are combined.

It means mixing science with voodoo.

Three Geometrizations in History

Juliano C. S. Neves writes a New paper:

There have been three geometrizations in history. The first one is historically due to the Pythagorean school and Plato, the second one comes from Galileo, Kepler, Descartes and Newton, and the third geometrization of nature begins with Einstein's general relativity. Here the term geometrization of nature means the conception according to which nature (with its different meanings) is largely described by using geometry. ...

Undoubtedly, the history of the geometrized nature begins in the ancient Greek period. ...

Then the third movement into the geometrization of nature begins with Einstein (1916) and general relativity, which I call geometrization 3.0. However, following Lehmkuhl (2014), contrary to the common opinion in physics, it is worth emphasizing that Einstein did not consider general relativity as the theory that geometrizes gravity. But, as we will see, general relativity brings a lot of geometrical concepts to describe the phenomena.

For attempts to take geometry out of general relativity, see Anderson 1999 and Brown 2009.

So if Einstein did not geometrize gravity, who did? Everyone else accepted relativity as a geometric theory.

Brown explains that Einstein took decades to come around to the geometric view that Poincare and Minkowski had in 1905-8.

Why this lapse on Einstein’s part? I wonder if it was not because of the misgivings he had about the way he formulated his 1905 paper, misgivings which grew throughout his life. First, there is little doubt that right from the beginning he was aware of the limited explanatory power of what he called “principle theories” like thermodynamics. Secondly, when he confessed in 1949 to having committed in 1905 the “sin” of treating rods and clocks as primitive entities, and not as “moving atomic configurations” subject to dynamical analysis, he was merely repeating a point of self-correction he made in 1921. Finally, it is fairly clear that Einstein was increasingly unhappy with the central role that electrodynamics, and in particular the behaviour of light, played in his 1905 paper.

This last aspect of Einstein’s reasoning brings us to the main point of this subsection. Einstein wrote in 1935:

The special theory of relativity grew out of the Maxwell electromagnetic equations. ... [but] the Lorentz transformation, the real basis of special-relativity theory, in itself has nothing to do with Maxwell theory. (Einstein 1935).

Similarly, in a 1955 letter to Born, Einstein would write that the “Lorentz transformation tran- scended its connection with Maxwell’s equations and has to do with the nature of space and time in general”. He went on to stress that “the Lorentz-invariance is a general condition for any physical theory.” (Born et al. 1971, p. 248). What is clear is that for the mature Einstein, the principle of Lorentz covariance, which applies to all the non-gravitational interactions, not just electrody- namics, is the heart of special relativity.8 In stressing this point, Einstein was distancing himself from his formulation of 1905 with its emphasis on fundamental phenomenological postulates (one of which being the “constancy” of the speed of light relative to the “rest” frame).

So Einstein finally adopted in 1935 the geometric view of relativity that Poincare published in 1905 and Minkowski improved and popularized in 1908. In that view, the Lorentz transformation is a symmetry of spacetime. It is a symmetry for any physical theory, and not just the Maxwell theory.

My theory is that the third geometrization occurred with Poincare and Minkowski in 1905-8. They both described it as a radical break from existing thinking. Poincare said that the new geometry was like Copernicus replacing Ptolemy, and Minkowski said that henceforth space and time will be united. The essence of special relativity is that there is a non-euclidean geometry on spacetime. Einstein missed it, but it is what make special relativity so popular with others.

Here is Sean M. Carroll describing the geometry of relativity, in his recent book:

But he didn’t go quite so far as to advocate joining space and time into a single unified space-time. That step was left to his former university professor, Hermann Minkowski, in the early 20th century. The arena of special relativity is today known as Minkowski space-time. ...

But, says relativity, just as the distance as the crow flies is generally different from the distance you actually travel between two points in space, the duration of time that you experience generally won’t be the same as the universal coordinate time. You experience an amount of time that can be measured by a clock that you carry with you on the journey. This is the proper time along the path. And the duration measured by a clock, just like the distance traveled as measured by the odometer on your car, will depend on the path you take. ...

The difference is this: In space, a straight line describes the shortest distance between two points. In space-time, by contrast, a straight path yields the longest elapsed time between two events. It’s that flip from shortest distance to longest time that distinguishes time from space.

Euclidean geometry has the shortest distance between two points is given by the Pythagorean theorem. Distances in the non-euclidean geometry of spacetime work differently.

Of course he does have to give some goofy reason to credit Einstein, as everyone else does:

The development of relativity is usually attributed to Albert Einstein, but ...

Einstein’s contribution in 1905 was to point out that the ether had become completely unnecessary, and that we could better understand the laws of physics without it.

No, this is a myth. What Einstein said about the aether was nearly identical to what Lorentz said ten years earlier. That is, they both rejected theories that depended on aether motion or motion against the aether, and their theories avoided mentioning the aether. Einstein could never explain how his theory was different from Lorentz's. Poincare and Minkowski did explain how their relativity theory was different, and the difference was non-euclidean geometry, not aether.

Professor has Trump Derangement Syndrome

Scott Aaronson is going nuts again, and posting crazy anti-Trump rants.

I cannot even figure out what he is complaining about. I expect him to complain for four years, no matter what.

He is entitled to his political views, but he cannot explain how Kamala Harris would have been better than Donald Trump on anything.

He believes in many-worlds theory, so I should not expect him to be rational about anything.

Update: Here is a physicist trying to reason with his fellow academic leftists:

The thoughtlessness of guilt by association

We cannot judge ideas on the basis of the people who happen to hold them

I am surprised that this needs to be said. You would think that professors would be trained to judge ideas on their merit. No, he says the leftists are engaged in an ideological war, where leftists favor transgendering children in order to maintain an opposition to right-wingers like Trump.

Summarizing Many-Worlds Theory

A new paper summarizes many-worlds:

Revolutionizing Quantum Mechanics: The Birth and Evolution of the Many-Worlds Interpretation

The Many-Worlds Interpretation (MWI) of quantum mechanics has captivated physicists and philosophers alike since its inception in the mid-20th century. This paper explores the historical roots, evolution, and implications of the MWI within the context of quantum theory. ...

One common critique of the MWI is its apparent lack of empirical testability. Critics argue that the MWI’s postulate of multiple parallel universes is inherently unobservable, making it difficult or impossible to distinguish experimentally from other interpretations of quantum mechanics. ...

Another criticism centers on the ontological status of the branching worlds in the MWI. Critics question whether the proliferation of parallel universes is necessary or justified, arguing that it introduces unnecessary complexity and violates principles of parsimony [32].

Yes, those criticisms are devastating.

One of the key impacts of the MWI is its resolution of the measurement problem in quantum mechanics. Unlike other interpretations that invoke wavefunction collapse or hidden variables to explain the transition from quantum to classical behavior, the MWI provides a deterministic and unitary description of the evolution of the quantum state. According to the MWI, measurements are merely instances of branching within the multiverse, with each possible outcome manifesting in a separate branch.

Saying that we just see one branch is no more satisfying that saying that we just see the collapse. It fails to solve the measurement problem in the same way. One theory says the wavefunction collapses, and the other says it splits into branches. The differnce is that MWI posits the existence of zillions of other branches we do not see.

Furthermore, the MWI has profound implications for our understanding of quantum superposition and entanglement. In the MWI, superposition is viewed as a fundamental feature of quantum systems, with different branches of the multiverse corresponding to different states of the system.

We do not see those other branches, so they cannot explain entanglement.

Moreover, the MWI has led to new insights into the nature of probability in quantum mechanics. In the MWI, probabilities arise from the relative frequencies of different outcomes across multiple branches of the multiverse, rather than from inherent randomness or observer-dependent collapses of the wavefunction. This perspective offers a coherent and objective interpretation of probability in quantum mechanics, resolving longstanding debates about the nature of quantum uncertainty.

Here it goes off the rails. The MWI folks have never been able to make sense out of different branches having different frequencies or probabilities. They cannot calculate probabilities that way.

Additionally, the MWI raises philosophical questions about the nature of consciousness and free will. If every possible outcome of every quantum measurement occurs in a separate universe, then every possible choice or decision is realized in some branch of the multiverse. This perspective challenges traditional views of free will as the ability to choose between alternative possibilities, suggesting that free will may be illusory or relative within the context of the MWI.

Nothing good has come out of those questions.

It is an embarrassment that modern Physics takes this nonsense seriously. It is like a child's fairy tale. You get to imagine whatever you please, with no connection to reality.

The biggest failure is its misunderstanding of science and probability. Science is all about figuring out what can happen, and what is likely. You get the probability by maybe enumerating equally likely events, and dividing the count of predicted events by the count of all possibilities. Or something similar. MWI throws that all out the window, says all possible events are real, and refuses to say that any worlds are more likely than any others. It cannot give probabilities. It is profoundly contrary to the scientific method, and cannot be used for anything but stimulating a philosophical discussion.

Dr. Bee Pushes Superdeterminism Again

Sabine Hossenfelder discusses an obscure paper on quantum momentum, and then argues:

The total momentum is the same in both cases. But the 5:34 change is non-local. And that isn’t compatible with Einstein’s theory of General Relativity. 5:41 The only way you can solve this problem is to violate measurement independence, 5:47 that’s what’s sometimes called superdeterminism. It's probably, 5:52 by Bell’s theorem, the only way to fulfil local conservation laws in a measurement process. 6:00 This is so obvious. And all I can do is repeat this, hoping that eventually one day, 6:07 they’ll understand it. But if that day comes, we can then say that science progresses one 6:13 YouTube video at a time and you made it happen, so don’t forget to subscribe.

She says that the only theory compatible with quantum mechanics and relativity is superdeterminism, and this was proved by Bell's theorem.

This is just nonsense. There is no superdeterministic theory that is compatible with quantum mechanics, or relativity, or anything else.

Bell opened up the possiblity of Physics being governed by a local hidden variable superdeterminism theory. But no one believes in either hidden variables or superdeterminism.

She gets some criticism for talking about science that is outside her expertise, but this is squarely within her core expertise. She should know better.

Typical Atmospheric Mind

FBI assessment of Paul Erdos:

[Erdos] is in the abstract field of mathematics and is purely a mathematician with typical atmospheric mind as related to factual things, that is, he is of the genius type who lives within his mental scope, and that it is difficult to know him personally.”

More in this recent video. Apparently they wondered why he avoided national loyalties, and how he has good ties in Communist countries.

The Existential Crisis Iceberg

Youtuber Alex O'Connor summarizes The Existential Crisis Iceberg.

There is an assortment of philosophical theories that deny our existence, and make everything not what they appear to be. I have discussed examples here, such as the simulation hypothesis, many-worlds theory, and superdeterminism. There are more.

Most of these cannot really be proved true or false, but believing them requires abandoning science as we know it.

Yes, I think it is beneficial to be aware of these theories, even it is kooky to believe in them.

Many worlds offers quantum immortality. Hugh Everett believed in this, reportedly. He would die in various branches of the universal wave function, but there would always be a branch in which he lives, and his consciousness would persist in that branch, so he would be immortal.

If you really believed this nonsense, you could buy a lottery ticket, and rig a machine to kill you if you do not win the jackpot. Your consciousness will then go with the branch that wins the lottery, and you will be rich.

Many physicists say that they believe in many-worlds theory, but they sure do not act like it.

Here is David Deutsch, trying to explain away the quantum suicide paradox. He describes a scenario, where you can stay at home and risk getting killed by a meteor from outer space, or drive to the grocery store and get killed in a car crash. A normal person would say that the meteor is so unlikely as to not worry about it.

But if you believe in many-worlds, it does not make sense to compare the probabilities of the parallel worlds. Both are just as real as each other. So why not play Russian roulette, or buy that deadly lottery ticket?

He says that he solved this problem. He says you have to make decision somehow, and a rational person will make decisions as if the probabilities are meaningful, so we get the same human behavior whether we believe in many-worlds or not.

I am not persuaded. Maybe I did not understand his argument. Listen for yourself.