Equilibration time scales of physically relevant observables
García-Pintos, Luis Pedro (University of Bristol. School of Mathematics)
Linden, Noah (University of Bristol. School of Mathematics)
Malabarba, Artur S. L. (Chapman University. Institute for Quantum Studies)
Short, Anthony J. (Chapman University. Institute for Quantum Studies)
Winter, Andreas (Institució Catalana de Recerca i Estudis Avançats)

Data:	2017
Resum:	We address the problem of understanding, from first principles, the conditions under which a quantum system equilibrates rapidly with respect to a concrete observable. On the one hand, previously known general upper bounds on the time scales of equilibration were unrealistically long, with times scaling linearly with the dimension of the Hilbert space. These bounds proved to be tight since particular constructions of observables scaling in this way were found. On the other hand, the computed equilibration time scales for certain classes of typical measurements, or under the evolution of typical Hamiltonians, are unrealistically short. However, most physically relevant situations fall outside these two classes. In this paper, we provide a new upper bound on the equilibration time scales which, under some physically reasonable conditions, give much more realistic results than previously known. In particular, we apply this result to the paradigmatic case of a system interacting with a thermal bath, where we obtain an upper bound for the equilibration time scale independent of the size of the bath. In this way, we find general conditions that single out observables with realistic equilibration times within a physically relevant setup.
Ajuts:	European Commission 323970 European Commission 267386 Ministerio de Economía y Competitividad FIS2013-40627-P Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-966
Nota:	Altres ajuts: Part of this work was supported by the COST Action MP1209 "Thermodynamics in the Quantum Regime".
Drets:	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.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Quantum physics ; Thermodynamics
Publicat a:	Physical Review, Vol. 7, issue 3 (Aug. 2017) , e031027, ISSN 2160-3308

DOI: 10.1103/PhysRevX.7.031027

19 p, 513.4 KB

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