Time-convolutionless non-Markovian master equation in strong-coupling regime

TL;DR

This paper demonstrates that the time-convolutionless (TCL) non-Markovian master equation remains valid in the strong-coupling regime despite previous beliefs, and introduces a multiscale perturbative method to solve it effectively.

Contribution

The paper challenges the notion that TCL master equations break down at finite times in strong coupling and proposes a new multiscale perturbative approach for solving them.

Findings

TCL master equation is valid in strong coupling despite singularities.

A multiscale perturbative method effectively solves TCL equations in strong coupling.

Ordinary perturbation methods fail in the strong coupling regime.

Abstract

The time-convolutionless (TCL) non-Markovian master equation was generally thought to break down at finite time due to its singularity and fail to produce the asymptotic behavior in strong coupling regime. However, in this paper, we show that the singularity is not an obstacle for validity of the TCL master equation. Further, we propose a multiscale perturbative method valid for solving the TCL master equation in strong coupling regime, though the ordinary perturbative method invalidates therein.