What is Fundamentally Quantum?

What makes quantum mechanics so strange, and so different from quantum mechanics?

Here is a common opinion:

Following the EPR paper, Erwin Schrödinger wrote a letter to Einstein in German in which he used the word Verschränkung (translated by himself as entanglement) "to describe the correlations between two particles that interact and then separate, as in the EPR experiment."[19] However, Schrödinger had discussed the phenomenon as early as 1932.[20]

Schrödinger shortly thereafter published a seminal paper defining and discussing the notion of "entanglement." In the paper, he recognized the importance of the concept, and stated:[3] "I would not call [entanglement] one but rather the characteristic trait of quantum mechanics, the one that enforces its entire departure from classical lines of thought."

Sometimes indeterminacy or other features are said to be fundamentally quantum.

I believe this is mistaken. I have said so many times on this blog, such as here. The only thing that fundamentally distinguishes quantum from classical mechainis is the noncommutation of observables.

Flavio Del Santo, Nicolas Gisin write a new paper:P

What is fundamentally quantum? We argue that most of the features, problems, and paradoxes -- such as the measurement problem, the Wigner's friend paradox and its proposed solutions, single particle nonlocality, and no-cloning -- allegedly attributed to quantum physics have a clear classical analogue if one is to interpret classical physics as fundamentally indeterministic. What really characterizes quantum physics boils down only to phenomena that involve $\hbar$, i.e., incompatible observables.

I agree with this. Classical mechanics is not really deterministic, if you take into account the fact that the variables can only be known to finite precision. Then classical and quantum mechanics are similarly indeterministic.

THe commutator of position and momentum is ℏ, ie h-bar, Planck's constant. That is the core of the uncentainty principle and everything that is truly quantum. There is no other fundamental quantum mystery.

The authors even point out that many-worlds theory can just as easily be applied to a classical theory. Just assume that all possibilities are real. It also says that there is a classical no-cloning theorem. I will have to think about that one.

How Galileo got the Diurnal Tides Wrong

Galileo was famously prosecuted for his 1632 book onheliocentrism. He had agreed not to advocate heliocentrism, but invited to write a book presenting alternate views. So he wrote the book as a dialog, with the Pope being a foolish character named Simplicio.

One thing I have never understand is how such a brilliant scientist could write this book making his main argument based on a completely bogus theory of tides.

Apparently he was fully aware that the Mediterranean Sea had tides contradicting his theory. But he claimed that the Lisbon tides supported his theory.

That is also wrong, and he was told that it was wrong.

A new paper takes a deep dive into the issue.

Galileo’s argument that the tides of the sea are a product of the motions of the Earth in a heliocentric universe needed diurnal tides to bolster it, because the driving action resulting from those motions would be diurnal. If diurnal tides existed, he could explain away other tidal periods as being a result of the local characteristics of sea basins. Given that when writing the Dialogue Galileo had on hand (thanks to Giovanfrancesco Buonamici) information from Andrés García de Céspedes on diurnal tides occurring in the East Indies, and given the reduced length of the Dialogue’s discussion of tidal periods and its content compared to Galileo’s 1616 discourse on tides to Cardinal Orsini — which included (in error) mention of diurnal tides occurring in the Atlantic at Lisbon — it seems reasonable to suppose that Galileo somehow overlooked adding the Céspedes information to the Dialogue. It seems as reasonable to make this supposition as it is to suppose (as has been done in the absence of awareness of Buonamici’s work) that Galileo clung to an idea in the teeth of adverse evidence, evidence that he even suppressed, leaving himself open to criticisms of his tidal theory in his time, and to the criticisms of modern scholars today.

A diurnal would be one high tide and one low tide per day. That's what Galileo thought, and needed to explain the motion of the Earth. Actually, the tides are caused by gravity, with two high tides and two low tides per day.

You are probably going to say that the Church should not have prosecuted him anyway, because the Church scholars were probably not smart enough to understand the errors in the tide theory. Maybe not, but they were smart enough to recognize that Galileo did not have a compelling argument for the motion of the Earth. It is fine to praise Galileo for his good ideas, but we should also recognize his errors.

It is important to get the Galileo story correct, as it is used as an example so much. India-American activist Sunil Mehta writes:

History offers a chilling precedent. In the 17thcentury, humanity teetered on the brink of intellectual darkness when the church, then the world’s most powerful institution, sought to suppress scientific progress and perpetuate the myth of a geocentric universe. Galileo Galilei, a pioneer of physics, dared to challenge this dogma with evidence showing that the Earth revolved around the sun. Threatened with death, he was forced to recant publicly. But legend has it that despite being compelled to disavow his theories aloud, he muttered under his breath: “And yet it moves!”

Whether or not this story is true, it metaphorically represents the intellectual fight that Galileo and many other brave individuals waged on behalf of science. Thankfully, in the end, darkness was averted and truth prevailed.

What? "Whether or not the story is true ... truth prevailed." And thanks to "brave individuals waged on behalf of science."

No, he is an embarrassment to science. Truth does not prevail by telling falsehoods.

It gets worse.

Today, we stand at a similar crossroads. The world’s most powerful nation, a beacon of intellectual freedom for centuries, is now in danger of coming under the control of a demagogue who wants to build an authoritarian regime on the foundation of misinformation and lies. A plague of intellectual darkness has infected half our nation. Hollow nationalism and misguided xenophobia have taken hold. It is hard to fathom this is happening in the 21st century, but the harsh reality is that a divided country and the quirks of the Electoral College could easily pave the way for an authoritarian future.

What can we do to avert this catastrophe? We must follow the example of Galileo and his followers and fight hard on behalf of truth and facts. The candidates in the upcoming election who are weaponizing misinformation (by making outlandish claims that immigrants are eating pets, for example) need to be soundly defeated.

He has this backwards. I wonder how long he has even been in the USA. The Biden-Harris administration has been much more authoritarian than Trump's, by any measure. The Democrats are the ones trying to restrict the free flow of information. California Democrats just passed a law against political parodies.

The Haitians in Ohio are not even immigrants. They have been allowed to stay temporarily for a couple of years. They are supposed to go back. There is some dispute about what animals they eat.

Whatever your political views, how does this relate to Galileo? The Catholic Church did not seek to suppress scientific truth, and neither does Trump. The whole thing is idiotic.

The Galileo story is told as a story of an authoritarian Church suppressing Galileo's truths. It is all a lie. No truths were supressed. It was not a truth that the Earth moved, because motion is relative, and Galileo had compelling argument for it. There were legitimate scientific arguments for and against. Galileo had a mixture of good and bad arguments.

It is a historical fact that science did best in Europe, under Christian domination. If the Christian authorities were so anti-science, then you might expect science to advance more rapidly away from the Christian authorities. Nope. Science advanced best under Christianity.

Sixth Reason for Quantum Computing Skepticism

Dr. Quantum Supremacy, Scott Aaronson, posted 5 reasons for quantum computing skepticism, and why he thinks they are reduced by recent research. I tried to post another reason, but it did not go through, so I post it here.

That is a good list of reasons, but does not include the main reason for my QC skepticism.

It is plausible that QC should be able to simulate QM reactions. But what is the intuitive argument for the super-Turing computations?

You say that QM uses amplitudes instead of probabilities, and they can be negative and interfere. Fine, but all waves show interference, and you cannot build a QC out of classical waves. There must be some special QM property that makes the magic possible. Possible candidates are: (1) an electron can be in two places at once; (2) two objects can be entangled, and influence each other instantaneously; and (3) a computer can make use of a calculation in a parallel universe.

Yes, these ideas are all magical, and make QC supremacy plausible. The trouble is that they are all dependent on QM interpretations that are not generally accepted. If one of those ideas is really the key to QC, then someone should have already demonstrated it with a Nobel prize-winning experiment. There was a 2022 prize for experiments ruling out local hidden variables, but those experiments just confirmed QM and did not show anything to make QC plausible.

Now a $100 million or more has been pumped into QC research, and yet there is still no convincing proof that QC is real. Fusion power has been a similar disappointment, but at least we have proof that fusing hydrogen into helium releases energy.

Brian Greene is still chasing Einstein's Dream

Peter Woit trashes a Brian Greene Wash. Post op-ed. Woit emphasizes the failures of string theory, but I want to point out how much foolishness is based on chasing Einstein's dreams.

Decades later, string theory continues its march toward Einstein’s dream

Forty years ago this month, the physics community was electrified by a remarkable paper that hinted at the realization of Albert Einstein’s long-held dream: a unified theory of physical reality. The new approach, called string theory, captured the attention of researchers worldwide, as its elegant mathematics offered the potential to reconcile the two most successful yet conflicting frameworks in physics: Einstein’s general theory of relativity, which governs the vast structures of the cosmos where gravity rules, and quantum mechanics, which governs particles populating the subatomic world. ...

The application concerns two papers that Einstein wrote in the spring of 1935. One analyzed “entanglement,” an iconic quality of quantum physics in which the behavior of two distant particles can be so tightly choreographed, it’s as if they have a secret connection bridging the space between them. Einstein famously called this connection “spooky.” ...

Although Einstein published these papers in the span of two months, he considered them completely unrelated. ...

But the duality between Einstein’s two 1935 papers would suggest that quantum mechanics and general relativity are already deeply connected — no need for them to marry — so our challenge will be to fully grasp their intrinsic relationship.

Which would mean that Einstein, without realizing it, may have had the key to unification nearly a century ago. ...

Einstein’s math suggested the big bang, black holes, dark energy and gravitational waves — all consequences that Einstein, who was a cautious revolutionary (human nature, again) considered too exotic to be true.

String theory has produced some interesting math, but no physics. This essay is mostly about Einstein, but he did not even believe in a lot of it. He was not a mathematician, and probably would not have liked string theory.

I am all in favor of discovering new mathematics, but that was not Einstein's dream.

String theory, as Greene describes it, has nothing to do with science. It is disconnected with experiment or explaining natural phenomena.

I believe that Einstein has been a bad influence on Physics. He did some good work, but he seems to be mainly idolized for his supposed dreams about mathematizing a unified field theory. Nothing good has come out of chasing that dream.

Greene is smart enough to know that his essay is nonsense. He is just plugging his book. The new media have no interest in mathematical advances. The math coming out of string theory is hard to explain. To sell physics research, it has to be a new discovery, or it has to be an Einstein essay. He could not get this essay published, if he removed the Einstein nonsense.

Medical Science recognizes Race and Sex

SciAm podcast: In recognition of Prostate Cancer Awareness Month this September, host Rachel Feltman sits down with Alfred Winkler, chief of urology at NewYork-Presbyterian Lower Manhattan Hospital, to discuss proactive steps individuals can take to protect themselves against prostate cancer. Black American men, in particular, face some of the highest rates of the disease in the world, with multiple factors contributing to this elevated risk. This episode explores efforts to raise awareness and promote early screening within this high-risk group. Other articles from the same magazine say Race Is a Social Construct and Human Sex Is Not Binary.

It is funny how our scientific institutions have been taken over by people willing to say obvious wrong things in order to serve misguided ideas about social justice.

Update: A new SciAm podcast today interviews a drag queen about teaching math.

SciAm goes Political Again; gets Trump Derangement

announces:

In the November election, the U.S. faces two futures. In one, the new president offers the country better prospects, relying on science, solid evidence and the willingness to learn from experience. She pushes policies that boost good jobs nationwide by embracing technology and clean energy. She supports education, public health and reproductive rights. She treats the climate crisis as the emergency it is and seeks to mitigate its catastrophic storms, fires and droughts.

In the other future, the new president endangers public health and safety and rejects evidence, preferring instead nonsensical conspiracy fantasies. ...

Only one of these futures will improve the fate of this country and the world. That is why, for only the second time in our magazine’s 179-year history, the editors of Scientific American are endorsing a candidate for president.

Harris and Walz are probably the most incompetent candidates for President in a long time. Harris avoids questions, and in the recent debate and interviews, she just babbled nonsense instead of answering the questions. When asked the simplest questions about what she plans to do or how she differs from Pres. Biden, she cannot answer.

This is science, so I looked for some example of Harris relying on science, following evidence, or learning from experience. No, there are no examples.

Trump touted his pandemic efforts during his first debate with Harris, but in 2020 he encouraged resistance to basic public health measures, spread misinformation about treatments and suggested injections of bleach could cure the disease. By the end of that year about 350,000 people in the U.S. had died of COVID; the current national total is well over a million.

This is all nonsense. Yes, thousands died under Trump, but more died under Biden-Harris. Trump never suggested injections of bleach. I don't think he even used the word "bleach". He merely commented on a scientific presentation on using disinfectants on surfaces to kill covid. Yes, Trump did downplay the shutdowns that health authorities were recommending, but we now know that the shutdowns did more harm than good.

It is hard to get any firm stand by Harris on any issue, except that she is pro-abortion, and against any restrictions on it.

Trump appointed the conservative U.S. Supreme Court justices who overturned Roe v. Wade, removing the constitutional right to a basic health-care procedure. He spreads misinformation about abortion—during the September debate, he said some states support abortion into the ninth month and beyond, calling it “execution after birth.” No state allows this.

Some states do allow abortions in the ninth month, and Trump correctly cited the Virginia governor as favoring it after birth.

The Biden-Harris administration’s 2023 Executive Order on Safe, Secure and Trustworthy Development and Use of Artificial Intelligence requires that AI-based products be safe for consumers and national security.

Really? Has that order made AI safe? Of course not. A science magazine should be able to back up what it says.

People can have political disagreements, and many will prefer Harris for various reasons. But a science magazine should stick to science. If it comments on a political race, it should be able to give evidence that a candidate is better for science.

There is no sign Harris understands any science issue. Reporters confronted her on her flip-flops on fracking, and she was unable to explain her views, and may not even know what fracking is.

New Research in Quantum Fault-tolerance

Dr. Quantum Computing has spent the last couple of years working for OpenAI, and returns to announce:

Let me end by sticking my neck out. If hardware progress continues at the rate we’ve seen for the past year or two, then I find it hard to understand why we won’t have useful fault-tolerant QCs within the next decade. (And now to retreat my neck a bit: the “if” clause in that sentence is important and non-removable!)

I think they created one logical qubit that lasts for a millisecond or so. Or something like that, I did not read the details.

I am just passing this prediction along. Seems doubtful to me.

The Invention of Large Language Models

Most people think that LLMs were invented by Google in 2016, or by OpenAI several years later.

AI expert Andrej Karpathy wrote on his blog:

The Unreasonable Effectiveness of Recurrent Neural Networks

May 21, 2015

The concept of attention is the most interesting recent architectural innovation in neural networks.

He constructs some LLMs, and his results seem pitiful compared to what is done today, but I would say he has a proof of concept.

Google introduced the transformer in Attention Is All You Need, a 2017 paper. As you can see, attention was already a hot idea at the time.

I am not sure who should get credit for inventing LLM. The basic ideas of neural nets go back decades. They got a whole lot smart when gaming GPU chips became fast and widely available, and AI researchers figured out how to use them efficiently.

No Quantum Nonlocal Effects

This is an elementary fact about quantum mechanics.

Dr. Bee explains:

Most importantly, if you do something to one of the pair of entangled particles, 4:46 that does nothing to the other. Say you turn the spin of the particle on the right upside-down 4:53 even though you don’t know what it is. Then the spin of the other particle doesn’t change at all. 4:59 No, it doesn’t. You wouldn’t believe how often I see even physicists get this wrong. I just 5:05 the other day heard a talk from someone who works on quantum computing for heaven’s sake 5:10 who said that if you manipulate one of a pair of entangled particles then that will non-locally 5:16 affect the other. It will not. It’s just that if you make a measurement on one of the particles, 5:23 then that will tell you something about the other. Because they’re correlated. ...

The person who 5:50 makes a measurement on one end can’t tell that a measurement was even done on the other end. 5:56 So: Entanglement is real, we know that. Whether spooky action is real is still a matter of debate, 6:04 but you can’t send information faster than light with either.

She is correct. No one has ever found any nonlocal quantum effects. Just correlations.

It should not be complicated. The same happens classically.

What she says about "spooky action" is a little confusing, so here is her explanation.

2:36 Strange or not, Bohr said that when we measure a particle, 2:40 this superposition “collapses” and suddenly the particle is in only one place. It’s this collapse 2:47 that Einstein referred to as spooky action. Because it would indeed be faster than light. 2:53 The moment you find the particle in one place, you instantaneously know it can’t be elsewhere. 3:00 Einstein disagreed with Bohr. Einstein thought that quantum particles are really only in one 3:06 place and that the sudden update of the wave-function just means that you 3:10 have learned the particle isn’t elsewhere. And his main argument, here it comes, was that by 3:17 claiming the collapse is a physical process, Bohr was introducing a “spooky action at a distance”. 3:26 Even if this spooky action existed though, it couldn’t transfer information. Just because you 3:32 find out what’s going on elsewhere doesn’t mean you sent information there.

When you find a classical particle, you immediately know it cannot be elsewhere. If that is spooky, then classical mechanics is spooky. Regardless, no information or anything else goes faster than light.

Usually she branches into a plug for superdeterminism. Mercifully, she did not this time.

Five Ways to Think About Quantum Supremacy

Aventine reports:

When Google announced that it had achieved quantum supremacy in 2019, the headlines were thrilling.

The world of quantum computing had taken a remarkable step. Google, with its Sycamore quantum processor, had performed a calculation in 200 seconds that, the company claimed in the journal Nature, would take a supercomputer 10,000 years.

This feat, named quantum supremacy by John Preskill, a theoretical physicist, back in 2012, promised to usher in a new world of computing performance. ...

Only it didn’t play out the way Google hoped or expected. ...

And then, earlier this summer, researchers from Shanghai Artificial Intelligence Laboratory in China completed the same task in just 14.22 seconds, driving a final stake through the heart of the Google quantum supremacy claim.

It’s not the only warning sign for the industry. Venture capital investment in the sector has fallen off a cliff, from $2.2 billion globally in 2022 to about $1.2 billion in 2023.

It then reports the opinions of five experts, but none of them say that quantum supremacy has been achieved. The closest is Scott Aaronson who says:

Quantum supremacy can be achieved and then unachieved later. It’s a little bit of a moving target in that sense. But all expect that we’ll eventually get to a place where quantum computers are just routinely doing things that classical computers cannot replicate within thousands of years or millions of years, and at that point there’s no more arguing about it.

Achieved and then unachieved? This is a bit like a mathematician saying something was proved, and then disproved. If it was later disproved, then it was never really proved.

Gil Kalai argues that quantum supremacy is impossible, and explains further here.