Driving many distant atoms into high-fidelity steady state entanglement via Lyapunov control

TL;DR

This paper presents a Lyapunov control-based scheme for generating high-fidelity W states of distant atoms in a cavity-fiber system, effective even with weak coupling and dissipation, using photon measurement, feedback, and time optimization.

Contribution

It introduces a novel Lyapunov control approach for robust entanglement generation in open quantum systems with dissipation.

Findings

Successful W state generation in weak coupling regimes.

Enhanced fidelity through photon measurement and feedback.

Reduced evolution time with time-optimal control.

Abstract

Based on Lyapunov control theory in closed and open systems, we propose a scheme to generate W state of many distant atoms in the cavity-fiber-cavity system. In the closed system, the W state is generated successfully even when the coupling strength between the cavity and fiber is extremely weak. In the presence of atomic spontaneous emission or cavity and fiber decay, the photon-measurement and quantum feedback approaches are proposed to improve the fidelity, which enable efficient generation of high-fidelity W state in the case of large dissipation. Furthermore, the time-optimal Lyapunov control is investigated to shorten the evolution time and improve the fidelity in open systems.