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https://www.quantamagazine.org/physicist...-20220526/

INTRO: In all of physical law, there’s arguably no principle more sacrosanct than the second law of thermodynamics — the notion that entropy, a measure of disorder, will always stay the same or increase.

“If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations — then so much the worse for Maxwell’s equations,” wrote the British astrophysicist Arthur Eddington in his 1928 book The Nature of the Physical World. “If it is found to be contradicted by observation — well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.” No violation of this law has ever been observed, nor is any expected.

But something about the second law troubles physicists. Some are not convinced that we understand it properly or that its foundations are firm. Although it’s called a law, it’s usually regarded as merely probabilistic: It stipulates that the outcome of any process will be the most probable one (which effectively means the outcome is inevitable given the numbers involved).

Yet physicists don’t just want descriptions of what will probably happen. “We like laws of physics to be exact,” said the physicist Chiara Marletto of the University of Oxford. Can the second law be tightened up into more than just a statement of likelihoods?

A number of independent groups appear to have done just that. They may have woven the second law out of the fundamental principles of quantum mechanics — which, some suspect, have directionality and irreversibility built into them at the deepest level. According to this view, the second law comes about not because of classical probabilities but because of quantum effects such as entanglement. It arises from the ways in which quantum systems share information, and from cornerstone quantum principles that decree what is allowed to happen and what is not.

In this telling, an increase in entropy is not just the most likely outcome of change. It is a logical consequence of the most fundamental resource that we know of — the quantum resource of information... (MORE - details)
Article author Phillip Ball writes:
"But the laws of classical physics are deterministic — they allow only a single outcome for any starting point. Where, then, can that hypothetical ensemble of states enter the picture at all, if only one outcome is ever possible?"

A nonsensical inference. Classically, there are a near infinite number of intermediate states occurring between a nominal 'start' and a hypothetical 'ending'. IF certain unrealistic simplifications are made, one of those states might hypothetically have all the air in the room crammed into one corner.

As far as QM fundamentally guaranteeing the 2nd Law, back in the 1980s I constructed a simple scenario, a classical optical arrangement that for sure reduced overall entropy. The reduction had no practical technological use imo so I deemed it 'safe' to disclose freely.
Everyone I explained it to initially agreed it would work, but once it was pointed out that violated the 2nd Law, eyes glazed over and heads were shaking. Except for one Dr of physics who finally understood what it all involved and wanted to write a joint paper. But at the time I wasn't after publicity but a patentable technology based on an ultimately unworkable alternate idea.
Then, in the late 2000s, someone else came up with a neat cylindrical geometry variant of my planar optics gedanken experiment, but operating in the microwave realm. Violation of the 2nd Law wasn't (outright anyway) claimed, but it was implicitly there. I could post a link to the latter, but why bother. Herd mentality ensures it would be rejected/ignored because, again, the thinking will be "all those experts can't be wrong".