Microcanonical and resource-theoretic derivations of the thermal state of a quantum system with noncommuting charges
Yunger Halpern, Nicole (California Institute of Technology (Estats Units d'Amèrica))
Faist, Philippe (Institute for Theoretical Physics. Department of Physics)
Oppenheim, Jonathan (University College London. Department of Physics and Astronomy)
Winter, Andreas (Universitat Autònoma de Barcelona. Departament de Física)

Date:	2016
Abstract:	The grand canonical ensemble lies at the core of quantum and classical statistical mechanics. A small system thermalizes to this ensemble while exchanging heat and particles with a bath. A quantum system may exchange quantities represented by operators that fail to commute. Whether such a system thermalizes and what form the thermal state has are questions about truly quantum thermodynamics. Here we investigate this thermal state from three perspectives. First, we introduce an approximate microcanonical ensemble. If this ensemble characterizes the system-and-bath composite, tracing out the bath yields the system's thermal state. This state is expected to be the equilibrium point, we argue, of typical dynamics. Finally, we define a resource-theory model for thermodynamic exchanges of noncommuting observables. Complete passivity-the inability to extract work from equilibrium states-implies the thermal state's form, too. Our work opens new avenues into equilibrium in the presence of quantum noncommutation.
Grants:	Ministerio de Economía y Competitividad FIS2013-40627-P Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-966 European Commission 258932
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Published in:	Nature communications, Vol. 7 (July 2016) , art. 12051, ISSN 2041-1723

DOI: 10.1038/ncomms12051
PMID: 27384494

7 p, 445.1 KB

The record appears in these collections:
Articles > Research articles
Articles > Published articles