Dynamics of interacting qubits coupled to a common bath: Non-Markovian quantum state diffusion approach

TL;DR

This paper derives a non-Markovian quantum state diffusion equation for two interacting qubits coupled to a common environment, revealing how environmental memory influences quantum coherence and entanglement dynamics.

Contribution

The authors derive the first exact non-Markovian QSD equation for coupled two-qubit systems without approximations, enabling detailed analysis of coherence and entanglement.

Findings

Environmental memory significantly modulates entanglement generation.

Strong non-Markovian effects lead to persistent residual entanglement.

The derived QSD equation accurately describes quantum coherence dynamics.

Abstract

Non-Markovian dynamics is studied for two interacting quibts strongly coupled to a dissipative bosonic environment. For the first time, we have derived the non-Markovian quantum state diffusion (QSD) equation for the coupled two-qubit system without any approximations, and in particular, without the Markov approximation. As an application and illustration of our derived time-local QSD equation, we investigate the temporal behavior of quantum coherence dynamics. In particular, we find a strongly non-Markovian regime where entanglement generation is significantly modulated by the environmental memory. Additionally, we studied the residual entanglement in the steady state by analyzing the steady state solution of the QSD equation. Finally, we have discussed an approximate QSD equation.