dorsal/arxiv
View SchemaQuantum Heat Engines, the Second Law and Maxwell's Daemon
| Authors | Tien D. Kieu |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0311157 |
| URL | https://arxiv.org/abs/quant-ph/0311157 |
Abstract
We introduce a class of quantum heat engines which consists of two-energy-eigenstate systems, the simplest of quantum mechanical systems, undergoing quantum adiabatic processes and energy exchanges with heat baths, respectively, at different stages of a cycle. Armed with this class of heat engines and some interpretation of heat transferred and work performed at the quantum level, we are able to clarify some important aspects of the second law of thermodynamics. In particular, it is not sufficient to have the heat source hotter than the sink, but there must be a minimum temperature difference between the hotter source and the cooler sink before any work can be extracted through the engines. The size of this minimum temperature difference is dictated by that of the energy gaps of the quantum engines involved. Our new quantum heat engines also offer a practical way, as an alternative to Szilard's engine, to physically realise Maxwell's daemon. Inspired and motivated by the Rabi oscillations, we further introduce some modifications to the quantum heat engines with single-mode cavities in order to, while respecting the second law, extract more work from the heat baths than is otherwise possible in thermal equilibria. Some of the results above are also generalisable to quantum heat engines of an infinite number of energy levels including 1-D simple harmonic oscillators and 1-D infinite square wells.
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"abstract": "We introduce a class of quantum heat engines which consists of\ntwo-energy-eigenstate systems, the simplest of quantum mechanical systems,\nundergoing quantum adiabatic processes and energy exchanges with heat baths,\nrespectively, at different stages of a cycle. Armed with this class of heat\nengines and some interpretation of heat transferred and work performed at the\nquantum level, we are able to clarify some important aspects of the second law\nof thermodynamics. In particular, it is not sufficient to have the heat source\nhotter than the sink, but there must be a minimum temperature difference\nbetween the hotter source and the cooler sink before any work can be extracted\nthrough the engines. The size of this minimum temperature difference is\ndictated by that of the energy gaps of the quantum engines involved. Our new\nquantum heat engines also offer a practical way, as an alternative to Szilard\u0027s\nengine, to physically realise Maxwell\u0027s daemon. Inspired and motivated by the\nRabi oscillations, we further introduce some modifications to the quantum heat\nengines with single-mode cavities in order to, while respecting the second law,\nextract more work from the heat baths than is otherwise possible in thermal\nequilibria. Some of the results above are also generalisable to quantum heat\nengines of an infinite number of energy levels including 1-D simple harmonic\noscillators and 1-D infinite square wells.",
"arxiv_id": "quant-ph/0311157",
"authors": [
"Tien D. Kieu"
],
"categories": [
"quant-ph"
],
"title": "Quantum Heat Engines, the Second Law and Maxwell\u0027s Daemon",
"url": "https://arxiv.org/abs/quant-ph/0311157"
},
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