Enhanced Entanglement in Hybrid Cavity Mediated by a Two-way Coupled Quantum Dot

Ming-Cui Li,Ai-Xi Chen

doi:10.1515/phys-2020-0003

Abstract

AbstractWe investigate theoretically the entanglement in a hybrid Fabry-Perot cavity system. A membrane in the cavity acts as a mechanical resonator, and a two-level quantum dot is coupled to both the cavity mode and the mechanical resonator. The entanglements between the cavity field and the mechanical resonator, between the mechanical resonator and the quantum dot, as well as between the cavity field and the quantum dot are observed. The logarithmic negativities in the first two subsystems are much larger than those in the system without two-way coupled quantum dot, and the entanglements are robust against the thermal temperature (entanglements still exist in tens of Kelvin). We also find that without direct coupling between the cavity field and the mechanical resonator, one can till observe effective entanglement between them in our system. Our work is helpful and may have potential applications in the research of multipartite entanglement in physical system.

Highlights

Entanglement [1], a fundamental phenomenon of quantum mechanics, has been considered to be a crucial resource for quantum communication [2] and information processing [3]
A membrane in the cavity acts as a mechanical resonator, and a two-level quantum dot is coupled to both the cavity mode and the mechanical resonator
We study the entanglement of the system in three subsystems: cavity field and mechanical resonator subsystem, mechanical resonator and quantum dot subsystem, cavity field and quantum dot subsystem

Summary

Introduction

Entanglement [1], a fundamental phenomenon of quantum mechanics, has been considered to be a crucial resource for quantum communication [2] and information processing [3]. Enhanced Entanglement in Hybrid Cavity Mediated by a Two-way Coupled Quantum Dot | 15 exciton–phonon coupling with a quantum dot embedded within a nanowire [31,32,33], spin-mechanical coupling of a quantum dots integrated into a cantilever resonator [34] Motivated by these developments, we consider a hybrid Membrane-in-Cavity with a quantum dot coupling both with the optical cavity and the resonator. The membrane is suspended within a high-Q Fabry-Perot cavity which is driven by an intense pump laser of frequency ωl Both mirrors of the cavity are fixed, and the membrane with a quantum dot serves as a membrane resonator in the cavity. The last term describes the interaction of the cavity mode with the pump laser.

Calculation

Entanglement between different components of the system

Conclusions