Controlling entanglement by direct quantum feedback

TL;DR

This paper explores how direct quantum feedback can generate and protect entanglement between two atoms in a cavity, comparing different control methods and analyzing robustness and experimental feasibility.

Contribution

It introduces a quantum-jump-based feedback scheme that enhances entanglement protection and provides analytical insights into its robustness against decoherence.

Findings

Quantum-jump feedback effectively protects entanglement.

Different control Hamiltonians influence entanglement generation.

Analytical results explain robustness and experimental considerations.

Abstract

We discuss the generation of entanglement between electronic states of two atoms in a cavity using direct quantum feedback schemes. We compare the effects of different control Hamiltonians and detection processes in the performance of entanglement production and show that the quantum-jump-based feedback proposed by us in Phys. Rev. A {\bf 76} 010301(R) (2007) can protect highly entangled states against decoherence. We provide analytical results that explain the robustness of jump feedback, and also analyse the perspectives of experimental implementation by scrutinising the effects of imperfections and approximations in our model.