Enhancing Quantum Discord in V-shaped Plasmonic Waveguides by Quantum Feedback

TL;DR

This paper demonstrates how symmetric quantum feedback control can enhance quantum discord in V-shaped plasmonic waveguides, revealing mechanisms that suppress Bell state degradation and proposing improved feedback strategies.

Contribution

It introduces a novel feedback control method that increases quantum discord in plasmonic waveguides and elucidates the operational mechanism behind this enhancement.

Findings

Quantum discord of Werner state increased from 0 to 0.38

Feedback confines evolution to a 3x3 subspace

Suppression of Bell state degradation

Abstract

We investigate the impact of a symmetric quantum feedback control on the quantum discord of the X state in V-shaped plasmonic waveguides. Under this feedback, the quantum discord of the Werner state is enhanced from 0 to 0.38. This value even continues to rise after reducing the decay rate of the atoms. Furthermore, we get the operational mechanism of feedback control through the evolution of the matrix elements. It confines the initial 4 * 4 matrix into a 3 * 3 subspace. As a result, the weights of each ground state in the quantum state change, which suppresses the degradation of Bell state. Lastly, we propose a direction for suggesting an improved feedback Hamiltonian.