Universität zu Köln

Lenarcic, Zala ORCID: 0000-0001-8374-8011, Lange, Florian and Rosch, Achim ORCID: 0000-0002-6586-5721 (2018). Perturbative approach to weakly driven many-particle systems in the presence of approximate conservation laws. Phys. Rev. B, 97 (2). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9969

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Abstract

We develop a Liouville perturbation theory for weakly driven and weakly open quantum systems in situations when the unperturbed system has a number of conservations laws. If the perturbation violates the conservation laws, it drives the system to a new steady state which can be approximately but efficiently described by a (generalized) Gibbs ensemble characterized by one Lagrange parameter for each conservation law. The value of those has to be determined from rate equations for conserved quantities. Remarkably, even weak perturbations can lead to large responses of conserved quantities. We present a perturbative expansion of the steady state density matrix; first we give the condition that fixes the zeroth-order expression (Lagrange parameters) and then determine the higher-order corrections via projections of the Liouvillian. The formalism can be applied to a wide range of problems including two-temperature models for electron-phonon systems, Bose condensates of excitons or photons, or weakly perturbed integrable models. We test our formalism by studying interacting fermions coupled to nonthermal reservoirs, approximately described by a Boltzmann equation.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Lenarcic, Zala UNSPECIFIED orcid.org/0000-0001-8374-8011 UNSPECIFIED Lange, Florian UNSPECIFIED UNSPECIFIED UNSPECIFIED Rosch, Achim UNSPECIFIED orcid.org/0000-0002-6586-5721 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-199177
DOI:	10.1103/PhysRevB.97.024302
Journal or Publication Title:	Phys. Rev. B
Volume:	97
Number:	2
Date:	2018
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2469-9969
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute for Theoretical Physics
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language BOSE-EINSTEIN CONDENSATION; NONEQUILIBRIUM STATISTICAL-MECHANICS; QUANTUM-SYSTEMS; TRANSPORT; EQUATIONS; MOTION; RELAXATION; EQUILIBRIUM; MICROCAVITY; POLARITONS Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/19917