Time-Local Quantum-State-Diffusion Equation for Multilevel Quantum Dynamics

TL;DR

This paper develops exact time-local quantum-state-diffusion equations for multilevel open quantum systems, enabling precise analysis of their non-Markovian dynamics without approximations.

Contribution

It introduces a systematic method to derive exact time-local QSD equations for various multilevel quantum systems in non-Markovian regimes.

Findings

Exact time-local QSD equations for multilevel systems established

Facilitates non-approximate analysis of complex quantum dynamics

Applicable to high-spin and atomic models with external fields

Abstract

An open quantum system with multiple levels coupled to a bosonic environment at zero temperature is investigated systematically using the non-Markovian quantum-state-diffusion (QSD) method [W. T. Strunz, L. Di\'osi, and N. Gisin, Phys. Rev. Lett. 82, 1801 (1999)]. We have established exact time-local QSD equations for a set of interesting multilevel open systems, including high-spin systems, multiple-transition atomic models, and multilevel atomic models driven by time-dependent external fields. These exact QSD equations have paved the way to evaluate the dynamics of open multilevel atomic systems in the general non-Markovian regimes without any approximation.