Optimal form of time-local non-Lindblad master equations

Fuente: arXiv
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Main Authors: Becker, Tobias, Eckardt, André
Format: Preprint
Published: 2023
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author Becker, Tobias
Eckardt, André
author_facet Becker, Tobias
Eckardt, André
contents Time-local quantum master equations that describe open quantum systems beyond the limit of ultraweak system-bath coupling are often not of Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) form. Prominent examples are the Redfield equation approximating general open quantum systems and the Hu-Paz-Zhang equation exactly describing a damped harmonic oscillator. Here, we show that not only the former, but also the latter can be brought to pseudo-Lindblad form, with a dissipator that resembles that of a GKSL equation, except for the fact that some of the terms have negative weights. Moreover, we systematically investigate transformations that leave the dissipator of pseudo-Lindblad equations unchanged, while changing the relative weight between its positive and negative terms. These can be used to minimize the weights of the negative terms, which is optimal both for the convergence of a recently developed quantum-trajectory unraveling of pseudo-Lindblad equations as well as for the truncation of the negative terms to obtain a GKSL equation.
format Preprint
id arxiv_https___arxiv_org_abs_2312_15066
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Optimal form of time-local non-Lindblad master equations
Becker, Tobias
Eckardt, André
Quantum Physics
Quantum Gases
Statistical Mechanics
Time-local quantum master equations that describe open quantum systems beyond the limit of ultraweak system-bath coupling are often not of Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) form. Prominent examples are the Redfield equation approximating general open quantum systems and the Hu-Paz-Zhang equation exactly describing a damped harmonic oscillator. Here, we show that not only the former, but also the latter can be brought to pseudo-Lindblad form, with a dissipator that resembles that of a GKSL equation, except for the fact that some of the terms have negative weights. Moreover, we systematically investigate transformations that leave the dissipator of pseudo-Lindblad equations unchanged, while changing the relative weight between its positive and negative terms. These can be used to minimize the weights of the negative terms, which is optimal both for the convergence of a recently developed quantum-trajectory unraveling of pseudo-Lindblad equations as well as for the truncation of the negative terms to obtain a GKSL equation.
title Optimal form of time-local non-Lindblad master equations
topic Quantum Physics
Quantum Gases
Statistical Mechanics
url https://arxiv.org/abs/2312.15066