Maximal Atom-Photon Entanglement in a Double-Lambda Quantum System

TL;DR

This paper investigates how a double-Lambda atomic system can generate and control atom-photon entanglement through phase and intensity adjustments, with potential applications in quantum information processing.

Contribution

It demonstrates phase-sensitive entanglement control in a double-Lambda system and explores conditions for maximal entanglement and disentanglement for quantum applications.

Findings

Entanglement is phase-sensitive and controllable by field intensity and phase.

Maximal entanglement occurs at specific Rabi frequencies.

Disentanglement occurs under electromagnetically induced transparency conditions.

Abstract

The atom-photon entanglement of dressed atom and its spontaneous emission in a Double-Lambda closed-loop atomic system is studied in multi-photon resonance condition. It is shown that, even in the absence of quantum interference due to the spontaneous emission, the von Neumann entropy is phase-sensitive and it can be controlled by either intensity or relative phase of the applied fields. It is demonstrated that, for the special case of Rabi frequency of the applied fields the system is maximally entangled. Moreover, the open-loop configuration is considered and it is shown that the degree of entanglement measure (DEM) can be controlled by intensity of the applied fields. Furthermore, in electromagnetically induced transparency condition, the system is disentangled. Such a system can be used for quantum information processing via entanglement using optical switching.