Quantum Mischief Rewrites the Laws of Cause and Effect

Re:Quantum Mischief Rewrites the Laws of Cause and Effect by antiquark on Saturday March 13, 2021 @04:40PM (#26450251)

How is this not a perpetual motion machine:

> engines normally need a hot and cold reservoir to work, with a quantum switch they could extract heat from reservoirs of equal temperature — a surprising use suggested a year ago by Oxford theorists.

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Re:Quantum Mischief Rewrites the Laws of Cause and Effect by lumost on Saturday March 13, 2021 @05:38PM (#26450782)

This is something akin to maxwell's demon. All Quantum processes save for measurement are reversible, and as such many thermodynamics concepts don't apply or don't apply in all circumstances.

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Re:Quantum Mischief Rewrites the Laws of Cause and Effect by ravi-delia on Sunday March 14, 2021 @12:33AM (#26453049)

It's worth noting that the measurement thing is what binds us to entropy's cold embrace in the long run. There's no maxwell's demon type thing that could run indefinitely without eventually having to perform something non-reversable, unless there's some horrible hack we haven't thought of yet.

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Re:Quantum Mischief Rewrites the Laws of Cause and Effect by LetThereBeLight on Saturday March 13, 2021 @11:46PM (#26452870)

This is still subject to Landauer's principle, at best it will cost kT ln2 energy per bit erased.

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