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The thermodynamic cost of driving quantum systems by their boundaries

The laws of thermodynamics put limits to the efficiencies of thermal machines. Analogues of these laws are now established for quantum engines weakly and passively coupled to the environment providing a framework to find improvements to their performance. Systems whose interaction with the environme...

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Autor principal: Barra, Felipe
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4597202/
https://www.ncbi.nlm.nih.gov/pubmed/26445899
http://dx.doi.org/10.1038/srep14873
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author Barra, Felipe
author_facet Barra, Felipe
author_sort Barra, Felipe
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description The laws of thermodynamics put limits to the efficiencies of thermal machines. Analogues of these laws are now established for quantum engines weakly and passively coupled to the environment providing a framework to find improvements to their performance. Systems whose interaction with the environment is actively controlled do not fall in that framework. Here we consider systems actively and locally coupled to the environment, evolving with a so-called boundary-driven Lindblad equation. Starting from a unitary description of the system plus the environment we simultaneously obtain the Lindblad equation and the appropriate expressions for heat, work and entropy-production of the system extending the framework for the analysis of new, and some already proposed, quantum heat engines. We illustrate our findings in spin 1/2 chains and explain why an XX chain coupled in this way to a single heat bath relaxes to thermodynamic-equilibrium while and XY chain does not. Additionally, we show that an XX chain coupled to a left and a right heat baths behaves as a quantum engine, a heater or refrigerator depending on the parameters, with efficiencies bounded by Carnot efficiencies.
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spelling pubmed-45972022015-10-13 The thermodynamic cost of driving quantum systems by their boundaries Barra, Felipe Sci Rep Article The laws of thermodynamics put limits to the efficiencies of thermal machines. Analogues of these laws are now established for quantum engines weakly and passively coupled to the environment providing a framework to find improvements to their performance. Systems whose interaction with the environment is actively controlled do not fall in that framework. Here we consider systems actively and locally coupled to the environment, evolving with a so-called boundary-driven Lindblad equation. Starting from a unitary description of the system plus the environment we simultaneously obtain the Lindblad equation and the appropriate expressions for heat, work and entropy-production of the system extending the framework for the analysis of new, and some already proposed, quantum heat engines. We illustrate our findings in spin 1/2 chains and explain why an XX chain coupled in this way to a single heat bath relaxes to thermodynamic-equilibrium while and XY chain does not. Additionally, we show that an XX chain coupled to a left and a right heat baths behaves as a quantum engine, a heater or refrigerator depending on the parameters, with efficiencies bounded by Carnot efficiencies. Nature Publishing Group 2015-10-08 /pmc/articles/PMC4597202/ /pubmed/26445899 http://dx.doi.org/10.1038/srep14873 Text en Copyright © 2015, Macmillan Publishers Limited http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Barra, Felipe
The thermodynamic cost of driving quantum systems by their boundaries
title The thermodynamic cost of driving quantum systems by their boundaries
title_full The thermodynamic cost of driving quantum systems by their boundaries
title_fullStr The thermodynamic cost of driving quantum systems by their boundaries
title_full_unstemmed The thermodynamic cost of driving quantum systems by their boundaries
title_short The thermodynamic cost of driving quantum systems by their boundaries
title_sort thermodynamic cost of driving quantum systems by their boundaries
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4597202/
https://www.ncbi.nlm.nih.gov/pubmed/26445899
http://dx.doi.org/10.1038/srep14873
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