Aaronson's Latest Lecture on Quantum Computers

Dr. Quantum Supremacy has posted a new lecture:

Title: The TRUTH About Quantum Computing
Date: 2026-05-13 @5:00PM

Abstract: Yes, scalable quantum computing should actually work! Sooner than many expect, which will create a huge headache when it breaks the encryption currently used to protect the Internet. But no, we don't think quantum computing can do most of what the popular articles promise in AI and optimization and so forth. Come to this talk to learn about why!

Somehow he has gotten to be the academic authority on whether quantum supremacy has been achieved, so I always check his latest opinion. He seems to be getting more confident, but it is still just a prediction. He says it may or may not be achieved. And that not to trust your RSA keys.

And another one:

Title: Scott Aaronson - Theoretical Computer Science and AI Alignment
Date: 2026-05-14 @1:00PM

Abstract: I'll survey some areas where I think theoretical computer science, math, and statistics can potentially contribute to the urgent quest to align powerful AI with humane values. These areas include: the watermarking of AI outputs, mechanistic interpretability (including Paul Christiano's "No-Coincidence Principle," and succinct digests of the training process to aid interpretability), and theoretical guarantees for out-of-distribution generalization.

Also on the subject, Dr. Bee dropped a new one today that starts:

In Einstein’s theory of general relativity, the time an object experiences depends on its acceleration. But time in quantum physics works more intuitively – it’s a universal parameter experienced by every object in the same way. In a new paper, physicists say they want to use a special type of clock to test that difference. Let’s take a look.

0:00 Quantum physics says that objects can be in two places at the same time. A group of physicists now says that they can also be at two times at the same time, ...

No, quantum physics does not say that objects can be in two places at the same time. It does not say that cats can be alive and dead at the same time.

Quantum computers are often explained this way, but QM really just estimates probabilities for different place. Once you observe the object, it is in just one place. Her statement is like saying: probability theory says that a tossed coin can be heads and tails at the same time.

Aaronson is an AI enthusiast: [11:40] AI is what "I would regard as, you know, maybe the most consequential technology, uh, that humans are ever going to be building."

Sean M. Carroll Lectures on Many Worlds

NewScientist just posted a marathon series of math lectures, but almost half of it is from a 5-year-old lecture, Sean Carroll: The many worlds of quantum mechanics, that is not even on math. He gave a similar lecture last year, The Many Worlds of Quantum Mechanics | Dr. Sean Carroll.

My disagreements start early. Carroll says:

Why does 7:14 quantum mechanics have this reputation of being so hard? Here's the answer. There's an amazing feature of quantum mechanics that was nowhere to be found in classical mechanics which says that what you observe when you look at a system is not what you see.

What you see and what is really there are two different things. There's a difference between what a thing is when you're looking at it and when you're not looking at it. What you can possibly see is much less than what really exists. This sounds weird. This sounds bizarre. like it's very very different than what we had in classical mechanics.

He is trying to say that reality is the wave function, which is not directly observable.

The word see and observe are synonyms. I do not get his explanation. Even in classical physics, there are things we cannot see. We cannot see the center of the Earth.

You might think that in that 14:03 circumstance, since quantum mechanics is the foundational theory for all of modern physics, you might think that the quest to understand quantum mechanics at a deep level would be recognized as one of the most important things we could possibly do in physics. The people who devoted their lives to these would be academic superstars. You would have different universities trying to steal them away with highpriced packages and salaries and so forth. and it would be the highest prestige occupation you could have in physics.

Sadly, no, that is not what we do. It is the opposite of that. We have adopted a strategy of denial where if you're a physicist and you think hard about answering these questions, you are labeled not a physicist or a physicist who is too old to do important work anymore and you're sent off to retirement.

That is because the important issues were settled in 1930. People like Carroll want to be paid to do research on many-worlds, and real physicists consider it a complete waste of time.

36:37 Another what I think incorrect objection is that this idea cannot be tested. Can it be tested Right? It's important in science that we not just have good ideas, but that we compare these important ideas to data. Right? that we experimentally probe our ideas and people say you've invented all these new worlds. How do you ever test that idea?

The response to that is, I didn't invent any new worlds. I just took quantum mechanics seriously. The entirety of the assumptions that go into the many worlds theory is there are wave functions and they obey the Schroinger equation. That's it. Everything else is a consequence, a prediction and implication of those assumptions.

And are those assumptions testable? Hell yes they are. Of course they are. Whenever we do a quantum mechanical experiment, we're implicitly testing the many worlds interpretation.

If you want to falsify the many worlds interpretation, remember that the prediction of many worlds is wave functions don't collapse. They never do. They appear to collapse because of decoherence.

So there is no way to test many-worlds. He says it is logically correct, so everything you see confirms it. That's all.

As he admits, we see wave functions collapses. They would contradict many-worlds, except that he does not believe that they are really collapsing. He calls that a test.

This is all nonsense. I don't know why anyone takes him seriously.

Carroll also has to answer this new survey:

World's largest ever survey of physicists, results & reaction

May 12, 2026
What do physicists really think about the biggest mysteries in the universe?

In this video, leading voices in theoretical physics come together to unpack the results of the Big Mystery Survey—the largest survey ever conducted of professional physicists, prepared in collaboration with the American Physical Society's Physics Magazine." Featuring reactions from experts like Sean Carroll, Niayesh Afshordi and ,Ghazal Geshnizjani we find out what physicists really think about topics such as: What should we think about fine tuning ? What is dark matter? What is dark energy? How should we truly understand the Big Bang?What the right approach to quantum gravity ?

Whether you’re a physics enthusiast or just curious about the universe, this conversation offers a rare glimpse into how experts think about the unknown.

It reports 11% for many-worlds, 6% for Bohm pilot wave. These are the two crackpot interpretations. It is amusing to see how the leading popularizers of theoretical physics have views that are rejected by most physicists.

Carroll also has a lecture in this newly-released video on the physics of time and the history of relativity.

[4:50] All you have to do is entirely jigger your thoughts about what space and time are. And in fact, it wasn't until two years later when Hermann Minkowsky, who was a mathematician who had been one of Einstein's professors, said, "You know, the right way to think about Einstein's theory is to say that space and time aren't separate anymore. To imagine there's one thing called spacetime, and different people, different observers moving in different ways through the universe will divide it up into space and time differently.

There's no objective true fact about when I snap my fingers now what's happening light years away. That's going to depend on who's doing the observing and who is doing the measuring. ...

It can all be explained very beautifully by imagining a single four-dimensional spacetime instead of separate space and time. Einstein himself was not impressed by this move. ...

And when Minkowsky says, "I have some new math that unifies space and time based on Einstein's theories," Einstein himself is like, "I don't need that. That's like extra mathematical nonsense."

Minkowski never referred to "Einstein's theory", but got that 4D spacetime from Poincare. That 1907 Minkowski paper cited Poincare's 1905 paper with the 4D spacetime.

Yes, people like to credit Einstein for spacetime, but that was published by Poincare and Minkowski, and Einstein rejected it.

Carroll wrote a whole book on relativity, so he surely knows the history. It is weird that he gets it so wrong.

Update: The survey has just been posted in a paper.

We present results from the Big Mysteries Survey, a large-scale survey conducted through the American Physical Society's Physics Magazine on foundational and controversial topics in contemporary physics. The survey provides a snapshot of physicists' views on issues in cosmology, black-hole physics, quantum mechanics, quantum gravity, and anthropic coincidences. A central finding is that several positions often described publicly as field-wide ``consensus'' views are, in practice, supported by much narrower majorities or by pluralities rather than majorities.

19% believe string theory is the best hope for quantum gravity. 30% believe that information dropped in a black hole is preserved in Hawking radiation. 24% believe in the dark energy cosmological constant. No consensus on dark matter. 51% believe in cosmological inflation.

The Most Cited Physicist Alive

Brian Keating interviews Juan Maldacena, The Most Cited Physicist Alive.

Juan Maldacena is a theoretical physicist at the Institute for Advanced Study whose 1997 paper remains the most cited in the history of theoretical physics.

We cover:
-why wormholes and quantum entanglement may be the same thing
-what actually happens to information when you throw something into a black hole
-the reason Hawking radiation accidentally gave cosmologists the equation that explains why the universe has structure
-whether science-fiction wormholes are ruled out by the laws of physics
-the one unsolved problem Juan says matters more than black holes.

The most important problem in quantum gravity is understanding the beginning of the Big Bang — not black holes.

And also the Holographic Principle, AI, complex numbers, etc.

Someone from 50 or 100 years ago would really be disappointed at what a dead-end theoretical physics. He rambles from one absurdity to another, with barely any relation to the real world.

The universe is not locally real

AI has risen Feynman from the dead, and explained Bell's theorem:

The Universe May Not Be Locally Real – Feynman Explains Bell’s Paradox

What if everything you believe about reality is wrong? In this mind-bending 23-minute exploration, Richard Feynman walks you through one of the most unsettling discoveries in the history of science — Bell's Theorem and the Nobel Prize-winning experiments that proved the universe is not locally real. From Einstein's stubborn belief in hidden variables to the groundbreaking work of Aspect, Clauser, and Zeilinger, this video breaks down quantum entanglement, the EPR paradox, and what it truly means when particles separated by miles somehow "know" what the other is doing — with no signal, no instructions, and no classical explanation.

It concludes:

[20:05] Let me bring it all together. Now we started with a simple idea that the world is locally real that things have definite properties that distant objects can't affect each other instantly. John Bell took this idea and turned it into a testable prediction. He said if local realism is true then the correlations between entangled particles must obey a mathematical limit. experiments culminating in the Nobel Prize winning work of aspect, Clauser, and Zelinger showed that the correlations exceed that limit. Local realism is violated. The universe is not locally real.

This means one of two things, or possibly both. Either particles don't have definite properties before they're measured, meaning reality isn't real in the way we thought, or distant particles can somehow affect each other instantly, meaning the universe isn't local in the way we thought. We don't know which. We don't have a complete agreed upon interpretation of quantum mechanics that resolves this.

I think we do have an agreed QM interpretation. It is the first option. Nobody thinks distant particles can somehow affect each other instantly.

The QM textbooks say that under Heisenberg uncertainty, it makes no sense for a particle to have a definite position and momentum at the same time. Particles only get definite values for position and momentum when they are measured, and you cannot measure both at the same time.

So yes, QM says particles don't have definite properties before they're measured. And I think that is what Feynman would have said, and not that this is an unsettled question.

Not everyone agrees with this, as maybe 10% of physicists subscribe to goofy interpretations like Bohm pilot wave or many worlds. But the mainstream textbook QM view is pretty clear on this point.

Hassabis likes a Wacky Book

Demis Hassabis says:

[25:41] well, my favorite book is The Fabric of Reality by David Deutsch. So, I think that still holds. I'd hope to answer the questions in that book with with the AGI. That's my post AGI work.

Hassabis is a genius, and certainly one of the world's leading AI researchers. But I am lowering my opinion of him, if this is his favorite book.

At first glance, the book is a celebration of modern science. It is enthusiastic about science, theory, the scientific method, explanations, and testability. It explains what science is all about.

Except that it is really anti-science. For all his talk about the merits to testing theories, he mostly promotes theories that cannot be tested at all. For all his talk about reality, he mainly believes in things that are not real.

His favorite ideas are Popper's falsification, Darwin's evolution, and many-worlds quantum mechanics. He raves about their explanatory power.

These are so bizarre, because many-worlds is just an unscientific belief that cannot be falsified.

Darwin evolution has some explanatory power, but the main principle -- survival of the fittest -- is a tautology. Fitness is defined as what survives.

Deutsch starts the book by attacking Steven Weinberg for saying an instrumentalist remark: "The important thing is to be able to make predictions". Weinberg's point was anti-geometry, not instrumentalism, and he later changed his mind when geometry proved crucial for theoretical physics.

For a more up-to-date description of Deutsch's opinions, see this new interview of him. He says that he now believes in free will, because we have the ability to create novelty.

[1:18:36] By the way, Bryce DeWitt said that he was sure that if Einstein had lived another few years, he would have come to like the Everett interpretation, because it's fully realistic.

I am pretty sure that Einstein would have hated many-worlds. Regardless, it is bizarre to say that many-worlds is "fully realistic". It is the opposite of realistic. Nothing is more unrealistic than postulating an infinity of parallel universes that have no interaction with ours.

Crypto Doom in 2029

Dr. Quantum Supremacy announces:

Will you heed my warnings NOW?

Holy crap … yesterday I was elected to the US National Academy of Sciences! ...

See, some of the most reputable people in quantum hardware and quantum error-correction — people whose judgment I trust more than my own on those topics — are now telling me that a fault-tolerant quantum computer able to break deployed cryptosystems ought to be possible by around 2029. ...

And I’d say that that makes my own moral duty right now ironically simple and clear: namely, to use my unique soapbox, as the writer of The Internet’s Most Trusted Quantum Computing Blog Since 2005^TM, to sound the alarm.

So, here it is: if quantum computers start breaking cryptography a few years from now, don’t you dare come to this blog and tell me that I failed to warn you. This post is your warning. Please start switching to quantum-resistant encryption, and urge your company or organization or blockchain or standards body to do the same.

He co-authored a paper on the threat to Bitcoin.

I say the opposite. There is no need to switch, and there is no chance of a break by 2029. [corrected] But I am not a member of NAS. You have been warned. Check back in four years to see who is right.

Update: I looked at the consensus white paper, to see if it endorses the idea that quantum supremacy is inevitable or has already been proved. It does not:

A few distinguished mathematicians, computer scientists, and physicists, including Gil Kalai, Leonid Levin, Michel Dyakonov, and Gerard ‘t Hooft, have taken the position that quantum computing is impossible in principle—that what seem to others like engineering difficulties will in fact never be surmounted for some inherent reason. This could be true, for example, if quantum mechanics itself were to fail as we tried to scale up QC, or if we were to discover some new principle on top of quantum mechanics, which guarantees the existence of noise that violates the assumptions of the Threshold Theorem and therefore can’t be corrected by FTQC.

It’s important to understand that this was never a mainstream view among experts, at least since the discovery of FTQC in 1996. The mainstream view could be summarized by saying that, if quantum mechanics were to fail, or some new principle were to be discovered that “screens off” or “censors” QC, that would constitute a once-per-century revolution in physics, and would be vastly more surprising and exciting than “mere success” in building a QC that worked as the theory has long predicted. From a physics perspective, QC working as predicted is the conservative option.

So believing in QC is the conservative option, but it might not be possible.

How Hard Determinists Reject Free Will

New video:

Robert Sapolsky, Paul Bloom, and Lucy Allais debate whether free will exists and what this would mean for punishment and morality.

The deny free will, and are strong determinists.

0:33 [Host] So, Robert, um, do do you do you see your position as being driven by a defense of materialism or physicalism? Is that what is motivating you? That there's just no no alternative. you can't give any account of free will and therefore uh because you can't give an account of free will within the uh within the scientific framework uh you think that we have to then deny free will

[Sapolsky] basically I think by now the extent of scientific knowledge is such that it forms this matrix of explanation and that within that matrix um it is a purely materialistic one and every attempt to find free will lurking in there requires some sort of violation of show we know these matrices work. In that regard, I completely agree with Lucy um that trying to make sense of human behavior by going down to bosons is absurd.

I believe that this is just wrong as a matter of our scientific knowledge. There are no such completely deterministic matrices.

If you think I am wrong, tell me when did science prove determinism? Who wrote the paper? Who did the experiment? Who got the Nobel Prize? Why isn't this in textbooks?

Sapolsky just babbles gibberish when asked this question:

Isn't there still the question of well you presumably have made a decision uh at some level to take part in this debate. you you uh wrote a book trying to convince people of uh the idea that we should see free will as an illusion. And you were presumably doing that because you wanted to change their minds. But what was the point if they couldn't change their minds in the first place?

Sapolsky is probably the leading academic opponent of free will, and he is a crackpot.