Thursday, June 23, 2022

Dr. Bee Announces a New Book

Sabine Hossenfelder has posted a new co-authored paper:
What does it take to solve the measurement problem?

We summarise different aspects of the measurement problem in quantum mechanics. We argue that it is a real problem which requires a solution, and identify the properties a theory needs to solve the problem. We show that no current interpretation of quantum mechanics solves the problem, and that, being interpretations rather than extensions of quantum mechanics, they cannot solve it. Finally, we speculate what a solution of the measurement problem might be good for.

Okay, this is mostly conventional wisdom of the last 90 years. Quantum mechanics depends on measurements, without precisely defining it.

Does that make the theory inadequate?

If quantum theory is not a valid scientific theory, then maybe we need to redefine theory. We have a trillion dollar semiconductor economy based on the theory. It is the most commercially successful scientific theory of the XX century.

She has also announced a new book, and promises a whole chapter on free will.

EXISTENTIAL PHYSICS

A Scientist's Guide To Life's Biggest Questions

A contrarian scientist wrestles with the big questions that modern physics raises, and what physics says about the human condition

Not only can we not currently explain the origin of the universe, it is questionable we will ever be able to explain it. The notion that there are universes within particles, or that particles are conscious, is ascientific, as is the hypothesis that our universe is a computer simulation. On the other hand, the idea that the universe itself is conscious is difficult to rule out entirely.

According to Sabine Hossenfelder, it is not a coincidence that quantum entanglement and vacuum energy have become the go-to explanations of alternative healers, or that people believe their deceased grandmother is still alive because of quantum mechanics. Science and religion have the same roots, and they still tackle some of the same questions: Where do we come from? Where do we go to? How much can we know? The area of science that is closest to answering these questions is physics. Over the last century, physicists have learned a lot about which spiritual ideas are still compatible with the laws of nature. Not always, though, have they stayed on the scientific side of the debate.

I am glad to see her address these issues, but she believes in superdeterminism, which is as wacky as the simulation hypothesis that she mocks.

Michio Kaku writes:

In physics, the concept of a multiverse is a key element of a leading area of study based on the theory of everything. It’s called string theory, which is the focus of my research.
There are many different notions of the multiverse, and I cannot even tell which he is referring to.

Update: Dr. Bee writes in defense of superdeterminism:

In a superdeterministic model, these quantities de- scribe an ensemble [9] rather than an ontic state (hence rendering the measurement update of the wavefunction purely epistemic), but that doesn’t make superdetermin- istic models classical. This should not be surprising, given the purpose of superdeterminism is not to return to classical mechanics, but merely to return to locality.
This makes no sense to me. Quantum mechanics already has locality. Interest in superdeterminism arose as a loophole in Bell's theorem. If you want a classical theory to replace quantum mechanics, then it must be nonlocal or superdeterministic.

Update: In the current Physics Today, N. David Mermin denies that there is a measurement problem:

Many physicists dismiss this view with the remark that quantum states were collaps- ing in the early universe, long before there were any physicists. I wonder if they also believe that probabilities were updating in the early universe, long before there were any statisticians.

Niels Bohr never mentions a quantum measurement problem. I conclude with a state- ment of his that concisely expresses the above view that there is no such problem, provided both occurrences of “our” are read not as all of us collectively but as each of us individ- ually. “In our description of nature the purpose is not to disclose the real essence of the phenomena but only to track down, so far as it is possible, relations between the manifold aspects of our experience.” I believe that this unacknowledged ambiguity of the first per- son plural lies behind much of the misunderstanding that still afflicts the interpretation of quantum mechanics.

This view is becoming a minority, but it should be regarded as the textbook view.

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