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May 31

Memorandum for the Historical Record

"Let’s focus on the interesting scenarios where heat either flows out from the coldest bath or into the hottest bath (note that negative temperatures, which occur in systems with a finite number of states and corresponds to a hotter temperature than a positive one, are possible [3] ... When we look closer at the threequbits separately, we see a heat engine. This has the potential to design new functionalities in open quantum networks, where the subsystems have different roles to play."


Decades ago I predicted

W/Qin ~ 1 + |Tpositive/Tnegative| > 1

i.e. in idealized reversible limit heat flows from both the (classical( positive and negative (quantum) effective temperatures are converted completely to mechanical work.

i.e. over 100%  Carnot engine efficiency - not a violation of 2nd Law of Thermodynamics at all.

It is the CLASSICAL 2nd Law of Thermodynamics with Quantum Theory added to it giving a counter-intuitive prediction.

Nick Herbert disagreed with me at the time, but now it looks like I may have been right.