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### Is there any proof for the 2nd law of thermodynamics?

Are there any analytical proofs for the 2nd law of thermodynamics? Or is it based entirely on empirical evidence?
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### Can a substance have zero vapour pressure above absolute zero?

According to this Reddit thread, the answer is no, vapor pressure can't be zero when temperature is above absolute zero. I suspect the answer might actually be yes according to a precise definition I ...
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### Has anyone ever created a formal system for quantum mechanics? [duplicate]

I've heard that quantum mechanics is really hard to teach people how to fully understand. Maybe there are some statements that some people seem to be able to prove are true according to a certain ...
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### Is there any proof that a perpetual motion machine of the second kind is not possible?

According to The statistical nature of the 2nd Law of Thermodynamics, the second law of thermodynamics probably hasn't been proven to be absolute. That doesn't necessarily mean it hasn't been proven ...
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### Has the zeroth law of thermodynamics ever been proven?

Has the zeroth law of thermodynamics ever been proven? I know the zeroth law of thermodynamics probably follows from the second law of thermodynamics but according to The statistical nature of the 2nd ...
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### Why does time always flow forward?

According to the BBC Earth " Physics says that any event in our day-to-day lives could happen in reverse, at any time".Then why can't we just turn time backwards?
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### Does the scientific community consider the Loschmidt paradox resolved? If so what is the resolution?

Does the scientific community consider the Loschmidt paradox resolved? If so what is the resolution? I have never seen dissipation explained, although what I have seen a lot is descriptions of ...
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### Is black hole formation reversible if physics law holds even in time reverse?

As we know many situations still fulfill physics law if time is reversed, such as particle collision. But how about black hole formation? Suppose a star is turning to a black hole and starts to have ...
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### Perpetual motion machine of the second kind possible in nano technology?

First of all sorry for my English - it is not my native language. During my engineering studies at the university the thermodynamics professor told us that the "second law of thermodynamics is not ...
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### Entropy as an arrow of time

From what I understand, entropy is a concept defined by the experimentalist due to his ignorance of the exact microstate of a system. To say the number of accessible microstates $W$ of the universe is ...
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### Theoretical proof forbidding Loschmidt reversal?

In a famous debate, Loschmidt criticized Boltzmann's new theory of statistical mechanics by asking what would happen if the velocities of all the atoms were reversed. Typical objections are that such ...