Benchmarking quantum master equations beyond ultraweak coupling

Fuente: arXiv
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Autores principales: Breuer, C. S. Tello, Becker, T., Eckardt, A.
Formato: Preprint
Publicado: 2024
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author Breuer, C. S. Tello
Becker, T.
Eckardt, A.
author_facet Breuer, C. S. Tello
Becker, T.
Eckardt, A.
contents Recently, Nathan and Rudner derived a Gorini-Kossakowski-Sudarshan-Lindblad master equation from the Redfield equation. The claim is that the level of approximation is equal to that of the Redfield equation. Here we benchmark the Nathan-Rudner equation (NRE) against the exact solution of a damped harmonic oscillator and compare its performance to that of the time-dependent Redfield equation (RE). We find that which of the equations performs better depends on the regime considered. It turns out that the short-time dynamics is generally much better captured by the RE, whereas the NRE delivers results comparable to those of the rotating-wave approximation. For the steady state, in the high-temperature limit the RE again performs better and its solution approaches the exact result for ultrahigh temperatures. Nevertheless, here also the NR equation constitutes a good approximation. In the low-temperature limit, in turn, the NRE provides a better approximation than the RE. For too strong coupling, here the RE might even fail completely by predicting unphysical behaviour.
format Preprint
id arxiv_https___arxiv_org_abs_2403_08320
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Benchmarking quantum master equations beyond ultraweak coupling
Breuer, C. S. Tello
Becker, T.
Eckardt, A.
Quantum Physics
Quantum Gases
Recently, Nathan and Rudner derived a Gorini-Kossakowski-Sudarshan-Lindblad master equation from the Redfield equation. The claim is that the level of approximation is equal to that of the Redfield equation. Here we benchmark the Nathan-Rudner equation (NRE) against the exact solution of a damped harmonic oscillator and compare its performance to that of the time-dependent Redfield equation (RE). We find that which of the equations performs better depends on the regime considered. It turns out that the short-time dynamics is generally much better captured by the RE, whereas the NRE delivers results comparable to those of the rotating-wave approximation. For the steady state, in the high-temperature limit the RE again performs better and its solution approaches the exact result for ultrahigh temperatures. Nevertheless, here also the NR equation constitutes a good approximation. In the low-temperature limit, in turn, the NRE provides a better approximation than the RE. For too strong coupling, here the RE might even fail completely by predicting unphysical behaviour.
title Benchmarking quantum master equations beyond ultraweak coupling
topic Quantum Physics
Quantum Gases
url https://arxiv.org/abs/2403.08320