Nothing violates the speed of light

New video:Does quantum theory violate the speed of light? | Claudia de Rham, João Magueijo, and Tim Maudlin.

One guy says:

I don't think 0:32 anything is sacred. it's just it's not 0:35 religion./. right this is science.

Okay, but this is just wrong:

what John Bell proved is that there 7:32 are certain constraints on what any 7:34 theory can predict and quantum theory 7:38 violates those constraints and more 7:40 importantly in the lab you violate those 7:43 constraints that's what the Nobel Prize 7:45 was given for two years ago was 7:47 experiments demonstrating violations of 7:49 Bell's inequality. so I don't even think 7:51 it's an open question whether something 7:53 goes faster than light. we know that 7:56 there's causation that's faster than 7:58 light. how you implement that cleanly and 8:01 mathematically is another question and 8:03 that nobody's worked out quite yet and 8:06 it may be that in working that out we 8:08 will have to abandon or certainly deeply 8:10 modify the picture of space and time 8:13 given by general relativity.

No, the consensus is that nothing goes faster than light. Especially not causation. And they certainly did not give a Nobel Prize for showing anything faster than light in the lab.

Later on, he correctly points out that Michelson-Morley experiment had multiple interpretations, and did not directly measure the speed of light. He needs to apply that same thinking to the Bell experiments, and admit that they have multiple interpretations.

Michelson-Morley must have seemed unremarkable, except to people like Maxwell, who followed aether theories. The Bell experiments were even less remarkable, as they only confirmed what the theory had predicted for 50 years.

Dr. Bee rambles on how the present might be caused by the future, instead of the past:

I find it curious that quantum physics is even compatible with this teleological interpretation. 4:49 It suggests to me that our idea of causes coming before effects might be somewhat of 4:54 a bias based on our personal experience, and maybe not a fundamental property of nature.

That would also be causation going faster than light. It is going so fast that it goes backwards in time!

You can say nothing is sacred, and be open to new ideas. But any causation from the future, or from anything outside the light cone, would be bizarre and contrary to our whole scientific worldview. We have no evidence for it. And if we did, we would not know what to do about it. Anyone who proved it would deserve a Nobel Prize. It has not happened.

Physics Blogs Obsessed with Fascism

I have followed the blogs of Peter Woit (Not Even Wrong) and Scott Aaronson (Shtetl-Optimized), but both of them are increasingly unhinged. Woit just posted:

Scott,
Besides the fact that your goals are delusional, what I’m criticizing is your choice to pursue them by collaborating with a Fascist dictatorship. I’m not going to further waste time trying to deal with your delusions about what is going on here.

As for what universities should do now: they should fight in court, they should tell the truth, and they should not collaborate.

By "not collaborate", he means to allow disruptive anti-Israel demonstrations, and not cooperate with Trump administration demands to obey the law.

It is baffling to me how these men go so nuts over this.

Aaronson has typical liberal Jewish political opinions, and his wife is Israeli, so he is pro-Israel. No surprises there. He largely agrees with Trump administration efforts to support Israel and crack down on antisemitism, DEI, wokism, and disruptions on campus. But he is also a hard-core Trump-hater, and hopes Trump fails in in everything he does, even if he agrees with it.

Woit has been obsessively posting sympathies for the anti-Israel protesters, and for fanatical Trump hatred. Aaronson responds:

Let’s get this straight, Peter. You’re saying that you’re angry and miserable, not for any of the reasons that are immediately apparent, but instead, because a shadowy cabal of unnamed Jewish financial elites is pulling the strings behind the scenes for its own incomprehensibly nefarious purposes?

If that’s really what you think, don’t hold back! Say it loudly, clearly, and often, directly into the microphone.

Woit seems to think that Israel should be destroyed, or that Columbia is unduly influenced by Jewish donors. I am not sure. Woit is chicken to say. Most of the protesters seem to want to destroy Israel, and to celebrate terrorism against Israel.

We can have different opinions about Israel and the Jews. That does not bother me.

What I find bizarre is how both of these guys have total comtempt for the administrations of Columbia and other universities, and yet they are so vehemently opposed to any government accountability. Their one point of agreement is that Pres. Trump is a fascist dictator.

Trump is not a fascist dictator. He was popularly elected, and he is doing what he was elected to do. He is trying to cut government waste, and most federal academic grants go for wasted research.

These universtities do some good research, but I do not expect them to get much public sympathy. A lot of the research is garbage. They are overwhelmingly slanted to the political Left. They arrogantly oppose any accountability. They allows these stupid Gaza protests to disrupt everyone, when Gaza has nothing to do with the university mission.

The Jewish angle to this is weird, as the universities have lot of Jewish professors, students, and donors. They have a history of being pro-Jewish. Trump is also pro-Jewish in his policies. And yet the universities are overwhelmingly anti-Trump.

The universities do not need to be taking a stand on either Zionism or Trump. They get billions of dollars in aid, and they ought to comply with government demands to obey the law. And they ought to be willing to do sensible things like shutting down the Gaza protests, even if the request comes from Trump and they hate Trump.

Reading these blogs just further convinces me that academia has lost its way. Radical reform is needed, and you can sure of a lot more complaints.

Textbooks Define the Orthodox Interpretation

Some modern popularizers of quantum mechanics like to say that the theory lacks foundations; that it has been corrupted by the Copenhagen interpretation; that Copenhagen is nonsense because the ramblings of Niels Bohr were incoherent; that no one understands QM; that we need a new interpretation; etc.

All of that is false. The theory is spelled out in textbooks that are mostly in agreement. You could call the agreement the Copenhagen Interpretation, but calling it that sometimes get sidetracked into what Bohr meant, and not everyone agrees.

A new paper by Geoff Beck dives into what the textbooks say:

This work sets out to answer a single question: what is the orthodox interpretation of quantum mechanics? However, we adopt a different approach to that normally used. Rather than carefully surveying the precise details of the thoughts of Bohr and Heisenberg, we extract an orthodoxy empirically. To do this we review a collection of 33 textbooks on quantum mechanics, encompassing the most popular and prominent works of this nature. We then gauge their response to 12 propositions to build up a picture of exactly what is believed by an orthodox quantum mechanic. We demonstrate that this orthodoxy is largely unchanged over the past century, with some interesting emerging deviations, and has many aspects of Copenhagen-like viewpoints.

This is correct. We do have an orthodox version of the theory, and general agreement on most points for about a century. And it does not include parallel universes, nonlocal interactions, Bohmian ghosts, Bell beables, or any of that.

Orthodox QM is used all the time in computer chip industries, and many others. It has been spectacularly successful, both theoretically and commercially.

What Einstein Would Tell Trump

SciAm opinion piece:

Einstein offers a lesson for scientists who are protesting an out-of-control nationalist administration attacking U.S. science today ...

Einstein was one of the first public critics of the Nazi regime, which he never ceased to criticize. Today his powerful stance may appear natural and uncontroversial. It was different then. ...

What would Einstein tell Trump today? Einstein would urge Trump to strive for high morality in his actions, as the scientist so eloquently presented in a 1950 letter to a minister in Brooklyn, N.Y.:

The most important human endeavor is the striving for morality in our actions. Our inner balance and even our very existence depend on it. Only morality in our actions can give beauty and dignity to life.

Yes, Einstein was a Jew who opposed the Nazi, but his politics were nothing to admire. He was a Communist fellow traveler. UPI reported

In one of the final entries in the file, the FBI noted, 'Extensive investigation in U.S. reflected Einstein affiliated or his name extensively associated with literally hundreds of pro-Communist groups.

'No evidence of CP membership was developed,' it added.

The FBI file described Einstein as a 'pacifist' and a 'liberal thinker' affiliated in some way with more than 30 'Communist-front' organizations.

'He has opposed militarism and universal military training in the United States and has espoused world government,' the file said.

He frequently criticized the USA government, while refusing to criticize the Soviet Union.

Invention of Projective Geometry

SciAm reports:

This demonstration of his recently discovered laws of perspective is said to have occurred sometime between 1415 and 1420, if his biographers are correct. The use of the laws of perspective amazed bystanders, altered the course of Western art for more than 450 years and, more recently, led to mathematical discoveries that enable elliptic curve cryptography. This is the security scheme that underpins Bitcoin and other cryptocurrencies and has become a fast-growing encryption method on other Internet platforms as well.

The article explains how the above art inspired projective geometry, over the next few centuries.

You would think that Microsoft and Google would be able to quickly adapt to a superior software technology, but that has not happened.

Elliptic curve cryptography is a relative latecomer to the encryption game. The first suite of tools did not appear until 2004, far too late to become a standard for the Web but early enough to adopted by the inventors of Bitcoin, which launched in 2009.

Its status as the de facto standard for cryptocurrencies made people more familiar with it and more comfortable implementing it, although it still lags behind RSA encryption, the standard method in use today, by a wide margin.

Yet elliptic curve cryptography has distinct advantages over RSA cryptography: it provides stronger security per bit and is faster than RSA. An elliptic curve cryptographic key of just 256 bits is roughly as secure as a 3,072-bit RSA key and considerably more secure than the 2,048-bit keys that are commonly used.

Current thinking is to abandon elliptic curve cryptography, and switch to new quantum-resistant protocols.

The trouble is, if the industry could not switch from RSA to ECC, how will it switch to quantum-resistant?

ECC is superior to RSA in every respect, except compatibility with ancient systems. ECC is is faster, more secure, less error-prone, and smaller. The new quantum-resistant methods will be worse in all those things, except that it will supposedly resist some quantum computer that might be built in 50 years.

Most people think that non-euclidean geometry means curved manifolds, such as a sphere or hyperbolic space. But the original non-euclidean geometry was projective geometry. Projective geometry also indirectly led to the discovery of relativity.

Think of it this way. A geometry could be defined by the formula for the distance between two points. On a more elementary level, a geometry can be defined by what the lines are. In special relativity, the light rays are the lines of particular interest, and they are different from Euclidean geometry.

Carroll addresses Weaknesses of Many-worlds

I have criticized many-worlds theory as unscientific nonsense, as it requires rejecting probabilities, does not make predictions, and cannot reconcile theory with observations.

In case you doubt this, listen to Sean M. Carroll, a leading advocate of many-worlds. Here is his latest podcast:

19:02 Victor Tiffany says "After you answered my question about energy conservation in the many worlds interpretation of 19:08 quantum mechanics you added there are real worries that you can have about many worlds but energy conservation is 19:14 not a true scientific worry." So what are those real worries

i think I've said what the real worries are at different 19:20 times but you know not everyone listens to every word so I'll I'll it's worth mentioning again. It's been a while Um I 19:25 think there are two sets of worries that are that are valid um one is the 19:30 question of deriving the born rule the probabilities in many worlds and it's 19:36 not that I don't think we can I think we can I think I know how to do it but the 19:41 origin of probability in many worlds is very very different than what it would 19:46 be in a truly stochastic theory or in a truly stochastic theory. um single world 19:52 theory you can just say well there's something that we don't know and can never know about what will happen next 19:58 in quantum mechanics. And the best we can do is assign a probability to it And we can figure out what that probability is by looking at 20:05 the frequencies of previous events and we get that the born rule fits the data and it all sort of makes sense It's at 20:10 least it not only does it make sense but it's comfortable and familiar to us Okay

20:16 Whereas in many worlds as has been pointed out many many times uh every allowed outcome happens The word allowed 20:23 is super important there Some outcomes are not allowed all outcomes that are supported by the Schroinger equation and 20:30 the current state of the quantum state of the universe are allowed which is very very different than saying everything happens but anyway many 20:37 different uh outcomes actually do happen and with 100% probability they will 20:42 happen in one of the branches of the wave function. right if I have a spin that is a superposition of spin up and 20:48 spin down I measure its spin in one branch it's definitely going to be spin up in the other branch. it's definitely 20:53 going to be spin down nothing probabilistic about it So where do the probabilities come from and again.

I 20:59 think there's an answer to this question and it has to do with self-locating uncertainty and things like that But the 21:05 kind of answer it is is deeply different than the kind of answer it is in the case of a truly stochastic theory. And 21:11 therefore I think it is okay to worry that we are cheating Uh you know we know what the answer is that we want to get. 21:18 We want to get the borne rule We want to get that the probability is proportional to the wave function squared I think we do get that in a very natural way but a 21:25 very different way than what we're used to. So we should be thinking very very deeply about whether we're just cheating 21:31 ourselves.

The other thing to worry about in Everett is that it's a very austere 21:37 theory. So the origin of structure broadly construed in the quantum state 21:42 of the universe is a big question Why do we see a world with three-dimensional space and you know matter and energy 21:49 rather than just seeing a wave function. okay again I think it's perfectly possible to answer this question but I 21:56 think it is much less answered than the probability question because you know the answer that we want is a lot more 22:02 detailed and structured as it were than just the probability question.

So there's a lot of work to be done and this is one 22:09 of the biggest things that I'm working on myself right now um how do you take that abstract quantum wave function and 22:16 divide it up using words like emergence and coarse graining and and effective theories and things like that and say 22:22 that oh look there's a classical limit with matter and particles and things like that. The reason why this is a 22:29 uniquely Everettian problem is because Everett's theory is the simplest theory 22:34 of quantum mechanics. Um it is the one that doesn't have any extra stuff It just has the quantum state and the 22:41 Schrodinger equation.

Other approaches to quantum mechanics don't need to address 22:46 the structure problem because they just put the structure in as part of the 22:51 posits of the theory. You have particles moving in space if you're bohmian. You 22:56 have certain ways that the wave function collapses if you're an objective collapse person And all of these rely on 23:02 this extra structure. So they quote unquote answer the question by just in 23:08 you know making an assumption that it's there right and maybe it is there that's perfectly valid I think that it is 23:14 better if we can derive it from something more fundamental but that doesn't mean that it's not uh uh work to 23:21 actually do that derivation

If you listen carefully, he is acknowledging that these are problems with many-worlds. Probabilities do not make sense. Maybe it will all be explained by "self-locating uncertainty" or some other concept yet to be developed.

And it predicts wave functions as the "simplest theory", but no one has figured out how to relate the theory to what anyone observes.

The phrase "not even wrong" applies here. There is no theory that is scientific in any way. It is all a delusional fantasy. He complains that Pres. Trump is probably not going to renew his federal grant to philosophize about this stuff, but this is crazier than transgender mice. There is no possibility of any good coming out of many-worlds theory.

Any scientific theory has to face the fact that if you look at the range of possible events, some things happen and some do not. Many-worlds theory says you get a simpler theory by dropping that fact, and assuming that anything can happen. It refuses to even say that some outcomes are more likely than others. It assures us that future work will make it all make sense somehow.

Listen to Carroll if you think I am misrepresenting many-worlds.

Columbia and Harvard are Anti-American

Peter Woit continues to rant:

Obviously I’m not a lawyer, but it’s impossible for me to believe that under the US constitutional system the president can legally issue an order to remove funding from an institution either because he thinks (see point 67 in the complaint) “Wouldn’t that be cool?” or because he wishes to take control of an institution he doesn’t like and remake it to his liking. ...

Since the beginning of this I’ve been highly frustrated by the difficulty of getting people (from the Columbia trustees on down…) to focus on what seems to me the simple and obvious issue: it’s a complete collapse of the US constitutional system to allow the executive to just defund an institution that displeases him, with the excuse for this defunding not relevant. If you accept that this is OK, you are accepting that dictatorship is OK.

No, it is not a dictatorship. Pres. Trump was popularly elected, and he is doing what he promised the voters.

Columbia and Harvard are anti-American. They break laws against racial discrimination. They are controlled by extreme leftists. They deny free speech to conservatives, while they coddle Gaza advocates who celebrate killing Jews. They get billions in government contracts, and overcharge for administrative overhead.

The colleges have an obligation to obey the law with the federal tax money they get. Every previous President threatened to withhold money if colleges do not comply. The only thing different today is that the colleges are dominated by Trump-haters.

Columbia and Harvard do a lot of good research, but most of it has no public value. The government is running big deficits, and a lot of things need to be cut.

Physicists have talked for decades on the benefits of string theory, anti-deSitter space, black hole interiors, supersymmetry, multiverse, and many other ideas of no practical value. It is all dishonest.

Scott Aaronson posted similar rants, but now announces

It’s crucial for people to understand that, in its total war against universities, MAGA has now lost, not merely the anti-Israel leftists, but also most conservatives, classical liberals, Zionists, etc. with any intellectual scruples whatsoever.

No. Harvard is suing Trump, but will likely lose on the main issues. Harvard will surely compromise, make some changes, and continue to be left-wing propaganda.

From a comment on Aaronson's blog:

I think it would be very beneficial to analyze the demands that Harvard fights so fiercely; perhaps some of them actually make sense. Would you mind if we take a look?

1. A non-specific preamble about leadership.

2. Merit-based hiring; no more racist preferences; screen for plagiarism. What’s wrong with any of that? Do you want less qualified professors with the politically preferential background? Do you want plagiarism?

3. Merit-based admission. What’s wrong with that? Do you want legacy and politically motivated student accepted and the most qualified rejected?

4. Pretty much “don’t admit Hamas operatives who misinform and inflame students.” What’s wrong with that? Do you want the horrible antisemitism of Harvard, Yale, Columbia to persist?

5. Viewpoint diversity. Indeed, social sciences and humanities department turned into echo chambers where academic discourse is effectively suppress. Would it be wrong to stop screening against conservatives and to allow faculty and students express a variety of opinions?

6. Stop antisemitism; report incidents of antisemitism. What’s wrong with that? Do you want the hatred to continue?

7. Get rid of DEI. DEI is one of major reasons for much of the above trouble. DEI is openly racist and contrary to merit-based hiring and admissions.

8. Accountability for misdeeds. Is anybody offended by the proposition that Harvard “forbids the recognition and funding of, or provision of accommodations to, any student group or club that endorses or promotes criminal activity, illegal violence, or illegal harassment”?

9. Whistleblower protection.

10. Transparency.

What’s so awful in any of these demands that Harvard should “fight fiercely”?

A lot of this has to do with Jewish issues, but my guess is that most Americans do not care about those issues, one way or the other.

Jews are going nuts with Hitler comparisons. Others wonder: was Hitler really trying to do the above ten items?

Woit refuses to admit that the colleges have a problem. Aaronson admits that the colleges have a problem, and agrees with Trump telling them to improve, but does not agree with Trump threatening to cut off money:

To win scientists’ everlasting love and support, all a more conservative political movement would need to offer is:

(2) We’ll fund and appreciate you, minus that other stuff.

All Trump can do is to threaten to cut off money, if he wants them to change. Columbia and Harvard have still refused to obey Trump's interpretation of the law.

Update: Aaronson and Woit still disagree.

My Definition of Science

I posted:

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

All science obeys all four steps, as far as I know.

I criticized many-worlds theory as only obeying the first two. It uses observations and the Schroedinger equation, but does not make predictions or reconcile experiments.

People find that surprising, but it is true. Making a prediction inherently implies that other things do not happen. But many-worlds theory says that all the other possibilities also happen. Probabilities are meaningless in the theory.

Astrology is better at being a science. It uses astronomy observations, has a theory, and makes predictions. It just doesn't reconcile experiments.

Ancient astronomy easily qualifies as science, even though they had flawed ideas about the underlying motions and causes.

Superdeterminism fails all four steps. It does none of them. It is not based on any theory or observations. Its advocates argue that our observations do not even reflect the natural laws, because unseen forces prevent us from testing those laws. If a drug seems to do better than a placebo in a controlled strudy, then it was only because the sicker patients were accidentally put into the placebo group.

String theory does not make predictions or reconcile experiments. Whether it does the first two steps is debatable.

A lot of theoretical physics today has no connection to experiment. An example is theorizing about the interior of a black hole. Or inflation-created universes beyond our horizon.

Watch Google Dodge Quantum Questions

This CNBC interiew is filled with quantum computer hype, and includes a Google quantum AI spokesman answering questions.

Not really. He dodges all the questions, and just babbles with things like "there's a lot of nuance in quantum computing".

Google Lost The AI Lead. Can Quantum Put It Back on Top?

I do not agree that Google lost the AI lead, or that quantum will help it in the AI race. Google has been a leader in AI for about 15 years. It is still at or near the top with protein folding, chess and go, and Gemini 2.5. And of course its big money-maker, which is using AI to target ads for everyone.

The supposed Google AI lead is based on a popular 2017 paper, but a new Nature journal survey rates a Microsoft AI paper as the most cited in the 21st century.

Scott Aaronson makes an appearance expressing skepticism about Microsoft's quantum computer.

In another video, physicist Angela Collier celebrates Bezos Blue Origin sending six women into space. Just kidding. She does a 40-minute rant against it.

And Peter Woit and Scott Aaronson are still arguing over the proper response to Trump being Hitler reincarnated. The basic facts are that Columbia and Harvard are extremely rich, they are not complying with federal law, they are receiving billions of dollars contingent on obeying federal law, they are refusing to comply, and they are squealing about Trump threatening to withhold those funds. Their faculties are dominated by leftist Trump-haters who do not want to compromise.

Woit and Aaronson think this could have been settled in quiet negotiations. Or maybe they think colleges should not have to obey the law, I am not sure. But it is extremely clear that Columbia and Harvard will not comply unless funds are withheld. Harvard already lost a racial discrimination case in the US Supreme Court, and it continues to discriminate as before.

The arrogance of these colleges was on full display when their presidents testified before Congress in Dec. 2023. The public backlash was so fierce that those presidents ended up resigning. You would think that these colleges would be eager to obey the law, but they stubbornly refuse.

Woit and Aaronson pointedly disagree on some Jewish issues, but that seems minor compared to their hysterical Trump hatred, and their overdramatizing of these colleges being held accountable. I doubt that they realize how much they seem like spoiled children.

Can Gravity be Renormalized?

A big achievement of XX century Physics was renormalizing quantum electrodynamics (QED), by Feynman and others. That showed how infinities could be canceled out, so the theory can make predictions in all energy ranges.

QED is a gauge theory on the circle group. Then 'tHooft showed renormalization applied to gauge theories over other groups. Since the known particles were classified by group representations of other groups, that opened the way to the Standard Model. They just had to use the groups already linked to the the particles, and apply gauge theory renormalization.

Gauge theory was the only known renormalizable theory, so there was no choice.

Not everyone agrees that renormalizability is so important. The later invention of effective field theory seemed to bypass renormalization. String theory also provides another approach.

Attempts to quantize gravity have failed because general relativity is not renormalizable. This led people to say string theory is the only game in town, except for maybe loop quantum gravity. Neither approach has produced a quantum gravity theory.

I did not know that general relativity could be easily modified to a theory that is renormalizable.

Luca Buoninfante posts a new paper:

An important theoretical achievement of the last century was the realization that strict renormalizability can be a powerful criterion to select Lagrangians in the framework of perturbative quantum field theory. The Standard Model Lagrangian (without gravity) is strictly renormalizable from a perturbative point of view. On the other hand, the inclusion of gravity seems not to respect this criterion, since general relativity is perturbatively non-renormalizable. The aim of this work is to provide concrete evidence that strict renormalizability is still a valid criterion even when applied to gravity. First, we show that adding quadratic curvature terms to the Einstein-Hilbert action gives rise to a strictly renormalizable theory known as quadratic gravity. Second, we argue that this unique theory represents the most conservative approach to quantum gravity and, at the same time, is highly predictive, as it can explain new physics beyond general relativity already in the sub-Planckian regime.

The simplest way to define a physics theory is to specify the Lagrangian. If you do that for the Standard Model, you can fit it on a t-shirt.

General relativity is the theory derived from the scalar curvature R being the Lagrangian. Or subtract a constant, for general relativity with a cosmological constant. This paper says that you just have to add a quadratic term in the curvature, such as R² or other contractions of the squared Riemann tensor, and you get a renormalizable theory. News to me. This model is sometimes called Starobinsky inflation, and used to explain the early universe.

We do not have any way to test quantum gravity, so the best argument for this approach is that renormalizability has been such a crucially important criterion in the past. It is how we got the Standard Model.

Adding a quadratic term is a bit like Einstein adding the cosmological constant to general relativity. It could not be measured at the time, and was intended to improve the global properties of the theory. It was only measured 80 years later.

Maybe someday this quadratic gravity will be seen as the natural way to modify general relativity to handle extreme conditions.

Everybody always says that quantum mechanics and gravity are incompatible. There is no experiment that shows a problem, so there is only a theoretical incompatibility that might only apply at the center of a black hole or in the first nanosecond of the big bang.

Now I question this. As this paper explains, just add a couple of quadratic terms to the gravity Lagrangian, and there is no problem renormalizing quantum field theory predictions. The only problem is that we do not have experimental data to determine the coefficients of those extra terms. Presumably they are small enough not to affect the known celestial mechanics and cosmology.

So we have a perfectly good quantum gravity theory, with a couple of undetermined coefficients. Those coefficients are too small to affect any of our observations. Viewed that way, it is incorrect to say that there is any incompatibility between gravity and quantum theories.

A few years ago, you could have said that general relativity was incompatible with the concept of a quantum zero point energy. Now the cosmological constant is accepted, and that is believed to be the energy. Maybe we just need to add one or two more cosmological constants, and quantum gravity will cease to be a theoretical issue.

About World Quantum Day

Monday was World Quantum Day:

This Doodle celebrates World Quantum Day, an annual celebration that improves understanding of quantum physics and technology. The date, April 14th, represents the first three digits of Planck’s constant, which describes the relationship between the energy and frequency of a quantum of energy (such as a photon): 4.14×10−15 eV·s

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.