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.

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.

Statistician Denies Probability Exists

Some say that quantum probabiliities are real and physical, while other say that all probabilities are just subjective estimates of human belief. I think neither is quite right.

David Spiegelhalter writes in SciAm:

Probability Probably Doesn’t Exist

All of statistics and much of science depends on probability—an astonishing achievement, considering no one’s really sure what it is ...

My argument is that any practical use of probability involves subjective judgements. ...

At the sub-atomic level, the mathematics indicates that causeless events can happen with fixed probabilities (although at least one interpretation states that even those probabilities express a relationship with other objects or observers, rather than being intrinsic properties of quantum objects). ...

There is a limited range of well-controlled, repeatable situations of such immense complexity that, even if they are essentially deterministic, fit the frequentist paradigm by having a probability distribution with predictable properties in the long run. These include standard randomizing devices, such as roulette wheels, shuffled cards, spun coins, thrown dice and lottery balls, as well as pseudo-random number generators, which rely on non-linear, chaotic algorithms to give numbers that pass tests of randomness.

In the natural world, we can throw in the workings of large collections of gas molecules which, even if following Newtonian physics, obey the laws of statistical mechanics; and genetics, in which the huge complexity of chromosomal selection and recombination gives rise to stable rates of inheritance. It might be reasonable in these limited circumstances to assume a pseudo-objective probability — ‘the’ probability, rather than ‘a’ (subjective) probability. ...

In several of those situations, a math calculation gives a probability that is accurate to several digits. This clearly reflects an objective physical reality, and not just a human belief. On the other hand, I don't think that probability is as real as energy or momentum. Probability cannot be directly measured, but only indirectly estimated by running repeated samples.

The proponents of many-worlds theory also deny that probably exists, for other reasons. They believe that all possibilities happen in their own universes, and that it makes no sense to say any are more likely than others.

Mathematical Truths can be Proved

SciAm gives this explanation of Goedel's theorem:

You will never be able to prove every mathematical truth. For me, this incompleteness theorem, discovered by Kurt Gödel, is one of the most incredible results in mathematics. It may not surprise everyone — there are all sorts of unprovable things in everyday life — but for mathematicians, this idea was a shock. After all, they can construct their own world from a few basic building blocks, the so-called axioms. Only the rules they have created apply there, and all truths are made up of these basic building blocks and the corresponding rules. If you find the right framework, experts long believed, you should therefore be able to prove every truth in some way.

But in 1931 Gödel demonstrated otherwise. There will always be truths that elude the basic mathematical framework and are impossible to prove. And this is not a purely abstract finding, without implications for practical situations. Shortly after Gödel’s groundbreaking work, the first provably unprovable problems emerged. For example, it will never be possible to clarify how many real numbers exist within the mathematical framework currently in use.

This is a typical explanation, and I know what they are trying to say, but it is misleading.

In spite of this, it may well be possible to prove every mathematical truth from the axioms, in some way. How would we ever know that it is the truth, unless it is proved in some way? It just might not be provable within a particular system.

People read this and conclude that the method of mathematical axioms and proofs does not work. But it does. Every provable statement is true in every model, and every statement true in every model can be proved from the axioms. Goedel proved that. That is what justifies using first order logic as the basis for mathematics.

ZFC serves as a suitable axiom system for all of mathematics.

Even before Goedel, it was known that set theory had countable models, so a model of the real numbers might have only countably many reals in use. Yes, it seems strange, but it does not undermine the use of axioms and proofs to find truths about reals. The set that enumerates those reals is not in the model.

People say it is shocking that a mathematical system cannot prove, from within the system, its self-consistency. But not really. Such a proof would not make much sense anyway. Inconsistent theories can prove their own consistency, as they can prove anything.

Goedel's incompleteness theorem was indeed a profound and important theorem, but popularizations of it are so misleading as to be not helpful.

Quantum Computer Stocks Rise and Fall

Quantum computer startup stocks have been skyrocketing, as Dr. Bee notes, but Nvidia just threw cold water:

The shares of IonQ Inc. and other companies linked to quantum computing tumbled on Wednesday, after Nvidia Corp. Chief Executive Officer Jensen Huang said that “very useful” quantum computers are likely decades away.

“If you kind of said 15 years for very useful quantum computers, that would probably be on the early side. If you said 30, it’s probably on the late side,” Huang said in a question-and-answer session during Nvidia’s analyst day. “If you picked 20, I think a whole bunch of us would believe it.”

Shares in Quantum Computing Inc., D-Wave Quantum Inc. and Rigetti Computing Inc. dropped more than 30%, while IonQ fell about 29%. These stocks have soared in recent months amid excitement about the technology’s potential, which was heightened last month following a quantum computing breakthrough by Alphabet Inc.

Nvidia has been profiting, a little, from the quantum computer hype and people simulate the QC on its processors.

I think that having a useful quantum computer in 20 years is optimistic. People do not usually invest, based on waiting 20 years to get a return.

Update: Dr. Quantum Supremacy weighs in:

yes, there’s a lot still to be done, and twenty years might well be correct. ...

On the other hand, I can’t say with certainty that high valuations are wrong! ...

For whatever it’s worth, my own family’s money is just sitting in index funds and CDs. I have no quantum computing investments of any kind.

Update: One of those QC companies responds:

Today’s classical computing hardware is limited by computational capacity and power requirements in ways that will likely prohibit society from ever being able to solve some of its most pressing problems.

IonQ’s current #AQ 36 Forte Enterprise systems are already providing insight to solutions for customers today, and our upcoming #AQ 64 Tempo systems in 2025 and next-generation #AQ 256 systems will enable us to tackle increasingly complex problems to deliver near-term business value. One of the areas facing the most significant potential disruption is strong AI, where we believe natively quantum AI will outperform classical AI.

No, quantum AI will not outperform classical AI in the next 50 years.

More Useless Quantum Teleportation

Quantum teleportation is a technology in search of an application.

News story:

An engineering team at Northwestern University has achieved a breakthrough in quantum teleportation, demonstrating the feasibility of transmitting quantum information alongside classic internet traffic. As research advances, we could enter a new era in communication technology, where quantum and traditional networks can coexist to offer unprecedented levels of security and speed.

Engineers at Northwestern University have demonstrated quantum teleportation over a fiber optic cable already carrying Internet traffic. This feat, published in the journal Optica, opens up new possibilities for combining quantum communication with existing Internet infrastructure. It also has major implications for the field of advanced sensing technologies and quantum computing applications.

Quantum teleportation, a process that harnesses the power of quantum entanglement, enables an ultra-fast and secure method of information sharing between distant network users. Unlike traditional communication methods, quantum teleportation does not require the physical transmission of particles. Instead, it relies on entangled particles exchanging information over great distances.

How can anyone make sense of this?

We already have cables efficiently and securely sending internet traffic. Now Northwestern engineers have figured how to use those cables to send messages over those cables without sending any particles! And they do it without interfering with the internet traffic on those cables! If they are not sending anything over the cables, whe do they need them?

I think I see what they are trying to say, but I do not see how it is of any value. It does not "offer unprecedented levels of security and speed." It is just a curiosity.

Another Youtuber attacks Hossenfelder

I mentioned Professor Dave attacking Sabine Hossenfelder, and now here is another:

The Fallacy of Sabine Hossenfelder
Quantverse

Dr. Sabine Hossenfelder is a popular science communicator, with often controversial views. In this video, I have attempted to take a critical look at the rise of Sabine, her involvement in string theory wars, recent controversy, and expert opinions.

she posts a lot of videos. so I am sure she gets some things wrong.

This attacks her on three points.

1. She says black hole information loss will never be measured.

2. She did a video on an unpublished argument about black hole singularities.

3. She believes in superdeterminism.

I agree with her on (1), and on (2) she seemed to be accurately reporting a paper that might be wrong.

For (3), the video relies on Tim Maudlin:

superdeterminism 18:19 explains Quantum Randomness by denying 18:21 statistical Independence

[Hossenfelder] about the 18:23 possible values of the Hidden variables 18:26 think about the hidden variables as 18:28 labels for the possible paths that the 18:30 particle could take say the labels 1 2 3 18:33 go to the left slit and the labels 456 18:36 go to the right slit and the label 7 to 18:38 12 go through both the particle really 18:41 has one of those hidden variables but we 18:43 don't know which then if we measure the 18:47 particles at the left slit that simply 18:49 tells us that the hidden variable was in 18:51 the one 12 three batch if we measure it 18:54 right it was in the 456 batch if we 18:56 measure it on the screen it was than the 18:59 7th to 12th batch no mystery no 19:01 instantaneous collapse no 19:04 non-locality but it means that the 19:06 particles path depends on what 19:08 measurement will take place because the 19:11 particles must have known already when 19:13 they got on the way whether to pick one 19:15 of the two slits or go through both this 19:19 is just what observations tell us and 19:22 that's what super determinism is now you 19:25 may say well drawing lines on YouTube 19:28 isn't proper science and I would agree 19:30 if you'd rather see equations you're 19:32 most welcome to look at my

[Quantverse] instead of 19:35 reading her papers let's see what Tim 19:37 Maudlin, a world leading expert, has to say 19:39 about 19:40 it.

[Maudlin] there are people who for reasons I do 19:43 not fathom, I just literally don't 19:46 understand their reasons, are are so 19:49 deeply committed to 19:52 locality that they're looking for any 19:54 Escape Route. I mean that's more or less 19:56 what we were talking about with these 19:57 with these loopholes with these 19:59 detection loopholes right they don't 20:01 like the idea of non-locality and 20:03 they're looking for any Escape they can 20:05 have from from accepting it and these 20:08 detection loopholes for many years were 20:10 one until the experimentalist just 20:12 closed those loopholes they're gone uh 20:15 so the only other loophole is they look 20:16 at this and they say well I don't want 20:17 to deny locality I guess I have to deny 20:20 statistical 20:21 Independence and the problem with 20:23 denying statistical Independence is that 20:25 it's kind of crazy and it's it's crazy 20:28 in conspiratorial and on top of it you 20:30 know as as you know I've said and other 20:33 people have said it undermines all 20:36 scientific method I 20:38 mean if in order to get out of accepting 20:41 non-locality you 20:44 deny what's required assumptions that 20:47 are required to do 20:50 science that's not a good 20:52 deal right that's a really bad 20:56 deal

I agree with Maudlin that superdeterminism is kinda crazy, and undermines the whole scientific enterprise. But I would say the same about the nonlocal quantum interpretations that Maudlin subscribes to. If nature is nonlocal, then the premises underlying much of science are wrong.

The problem is not that Hossenfelder is committed to locality, but that Hossenfelder and Maudlin are committed to hidden variable theories.

Yes, Hossenfelder has kooky views about superdeterminism that the vast majority of physicists reject. In fairness, she realizes this, and hardly ever talks about those views.

I am all in favor of criticizing science popularizers when they are wrong, but he needs to look up the word "fallacy". There is no fallacy.

She also has a new video attacking Gisin:

This Physicist Says We’re Using Maths Entirely Wrong

Intuitionist mathematics is the idea that the entire discipline of maths is a mental construct based on human thought rather than a platonic realm of eternal truths. According to physicist Nicolas Gisin, one of this idea’s biggest proponents, that maths is based on human intuition is the reason why quantum mechanics seems so strange. Let’s take a look.

I think she misunderstands Gisin. She does not link to him. Here is a Quanta article, and one of his papers. His gripe is about mathematizing nature, and it applies to classical or quantum mechanics.

In this video, Gisin attacks her for saying that free will is meaningless and contrary to science, and for her believing in superdeterminism. He is at the other extreme, and believes that classical and quantum theories are indeterministic.

I partially agree with Gisin, in that I believe in free will, and that the future is indeterminate. Infinities are not realizable in nature, and neither are real numbers having infinitely many decimal places. We only observe approximations to reals.