Sudden violation of the CHSH inequality in a two qubits system

TL;DR

This paper investigates the dynamics of CHSH inequality violations in two qubits interacting with a non-Markovian environment, revealing sudden violations and their damping due to spontaneous emission.

Contribution

It demonstrates the occurrence of sudden CHSH violation revivals in a non-Markovian setting and analyzes the damping effects of spontaneous emission on these violations.

Findings

Sudden revivals of CHSH violation occur in non-Markovian dynamics.

Spontaneous emission dampens and eventually suppresses violations.

Beyond a decay threshold, violations do not occur.

Abstract

I study the dynamics of the violation of the CHSH inequality for two qubits interacting with a common zero-temperature non-Markovian environment. I demonstrate sudden violation of the inequality for two qubits initially prepared in a factorized state. Due to the strong coupling between the qubits and the reservoir, the dynamics is characterized by numerous sharp revivals. Furthermore I focus on a more realistic physical system in which the spontaneous emission for the qubits is taken into account. When including spontaneous emission even for small decay parameters, revivals in the violation are heavily damped out. If the decay rates exceed a certain threshold, the inequality turns out to be always satisfied.