Entanglement and quantum discord dynamics of two atoms under practical feedback control

TL;DR

This paper investigates how practical feedback control affects entanglement and quantum discord between two atoms in a cavity, revealing that detection inefficiency can both diminish and enhance quantum correlations over time.

Contribution

It demonstrates that detection inefficiency can unexpectedly increase asymptotic entanglement and discord, and explores the dynamics and sudden changes in these quantum correlations.

Findings

Detection inefficiency causes entanglement to vanish in finite time.

Inefficiency can increase asymptotic entanglement and discord.

Sudden changes occur in the entanglement dynamics.

Abstract

We study the dynamics of two identical atoms resonantly coupled to a single-mode cavity under practical feedback control, and focus on the detection inefficiency. The entanglement is induced to vanish in finite time by the inefficiency of detection. Counterintuitively, the asymptotic entanglement and quantum discord can be increased by the inefficiency of detection. The noise of detection triggers control field to create entanglement and discord when no photon are emitted from the atoms. Furthermore, sudden change happens to the dynamics of entanglement.