Title: Thermodynamics of optical Bloch equations

Abstract

Abstract Optical Bloch equations (OBE) describe the coherent exchange of energy between a quantum bit (qubit) and a quasi-resonant driving field in the presence of a thermal bath. Despite it being an ubiquitous process in quantum technologies, a sound thermodynamic analysis is still missing. We hereby provide such an analysis, by deriving the relevant framework from first principles. We start from a complete microscopic description of the qubit-bath system where definitions of heat, work and entropy production are unambiguous. We trace out the bath and coarse-grain the resulting expressions in time, using a methodology similar to the derivation of the dynamical master equation, to derive closed expressions for the first and second law in terms of system properties. Long coarse graining times yield the Floquet Master equation and its already known thermodynamic description. Short coarse-graining times yield instead the OBE and a novel thermodynamic framework which explicitly depends on quantum coherences in the qubit’s energy basis which produce quantum signatures in the heat and entropy production flows. This allows us to characterize a genuinely quantum non-equilibrium situation, where the coherences created by the driving field are continuously erased by the bath. Our findings can be readily extended to larger openmore » quantum systems. They carry the seeds for future thermodynamic analyses of quantum gates and the design of quantum engines in the strong coherent driving regime.« less

Authors:

Elouard, Cyril; Herrera-Martí, David; Esposito, Massimiliano; Auffèves, Alexia

Publication Date:

Mon Oct 19 00:00:00 EDT 2020

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1678778

Resource Type:

Published Article

Journal Name:

New Journal of Physics

Additional Journal Information:

Journal Name: New Journal of Physics Journal Volume: 22 Journal Issue: 10; Journal ID: ISSN 1367-2630

Publisher:

IOP Publishing

Country of Publication:

United Kingdom

Language:

English