Invalidation of the Bloch-Redfield Equation in Sub-Ohmic Regime via a Practical Time-Convolutionless Fourth-Order Master Equation

Fuente: arXiv
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Main Authors: Crowder, Elyana, Lampert, Lance, Manchanda, Grihith, Shoffeitt, Brian, Gadamsetty, Srikar, Pei, Yiting, Chaudhary, Shantanu, Davidović, Dragomir
Format: Preprint
Published: 2023
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author Crowder, Elyana
Lampert, Lance
Manchanda, Grihith
Shoffeitt, Brian
Gadamsetty, Srikar
Pei, Yiting
Chaudhary, Shantanu
Davidović, Dragomir
author_facet Crowder, Elyana
Lampert, Lance
Manchanda, Grihith
Shoffeitt, Brian
Gadamsetty, Srikar
Pei, Yiting
Chaudhary, Shantanu
Davidović, Dragomir
contents Despite recent advances in quantum sciences, a quantum master equation that accurately and simply characterizes open quantum dynamics across extremely long timescales and in dispersive environments is still needed. In this study, we optimize the computation of the fourth-order time-convolutionless master equation to meet this need. Early versions of this master equation required computing a multidimensional integral, limiting its use. Our master equation accounts for simultaneous relaxation and dephasing, resulting in coefficients proportional to the system's spectral density over frequency derivative. In sub-Ohmic environments, this derivative induces infrared divergence in the master equation, invalidating the second-order Bloch-Redfield master equation findings. We analyze the approach to a ground state in a generic open quantum system and demonstrate that it is not reliably computed by the Bloch-Redfield equation alone. The optimized fourth-order equation shows that the ground-state approach is accurate to second order in bath coupling regardless of the dispersion, even though it can diverge in the fourth order at zero temperature.
format Preprint
id arxiv_https___arxiv_org_abs_2310_15089
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Invalidation of the Bloch-Redfield Equation in Sub-Ohmic Regime via a Practical Time-Convolutionless Fourth-Order Master Equation
Crowder, Elyana
Lampert, Lance
Manchanda, Grihith
Shoffeitt, Brian
Gadamsetty, Srikar
Pei, Yiting
Chaudhary, Shantanu
Davidović, Dragomir
Quantum Physics
Mesoscale and Nanoscale Physics
Mathematical Physics
Despite recent advances in quantum sciences, a quantum master equation that accurately and simply characterizes open quantum dynamics across extremely long timescales and in dispersive environments is still needed. In this study, we optimize the computation of the fourth-order time-convolutionless master equation to meet this need. Early versions of this master equation required computing a multidimensional integral, limiting its use. Our master equation accounts for simultaneous relaxation and dephasing, resulting in coefficients proportional to the system's spectral density over frequency derivative. In sub-Ohmic environments, this derivative induces infrared divergence in the master equation, invalidating the second-order Bloch-Redfield master equation findings. We analyze the approach to a ground state in a generic open quantum system and demonstrate that it is not reliably computed by the Bloch-Redfield equation alone. The optimized fourth-order equation shows that the ground-state approach is accurate to second order in bath coupling regardless of the dispersion, even though it can diverge in the fourth order at zero temperature.
title Invalidation of the Bloch-Redfield Equation in Sub-Ohmic Regime via a Practical Time-Convolutionless Fourth-Order Master Equation
topic Quantum Physics
Mesoscale and Nanoscale Physics
Mathematical Physics
url https://arxiv.org/abs/2310.15089