Response to "Comment on Universal Lindblad Equation for open quantum systems"

TL;DR

This paper clarifies that the Universal Lindblad Equation (ULE) accurately models open quantum systems with finite system-bath coupling, capturing effects beyond traditional master equations, and responds to critiques about its steady-state predictions.

Contribution

The authors clarify the scope and accuracy of the ULE in modeling steady states of open quantum systems with finite coupling, emphasizing its advantages over rotating wave approximation-based methods.

Findings

ULE captures finite coupling effects beyond RWA master equations

Steady state deviations from Gibbs are expected at finite coupling

Numerical results support the analytical claims

Abstract

In a recent comment, Lee and Yeo show that the Gibbs state is not generically an exact steady state of the Universal Lindblad Equation (ULE) that we developed in Phys. Rev. B 102, 115109 (2020). This non-controversial observation is precisely as expected for open quantum systems with finite system-bath coupling, where transition rates may be comparable to or larger than the level spacing of the system, and we made no claim to the contrary in our paper. The comment by Lee and Yeo hence highlights that the ULE captures contributions to the steady state due to finite system-bath coupling that are beyond the reach of master equations that rely on rotating wave approximations. In this response we further clarify the nature of our analytical and numerical results.