Engineering steady states using jump-based feedback for multipartite entanglement generation

TL;DR

This paper explores how jump-based quantum feedback can be used to create and stabilize multipartite entangled states in open quantum systems, offering practical strategies for generating complex entanglement.

Contribution

It introduces a general method for producing many-body singlet entangled states using quantum-jump feedback, including a feasible local control scheme for four qubits.

Findings

Successful stabilization of a highly entangled four-qubit state

Development of a realistic local feedback control strategy

Analysis of limitations and alternative feedback schemes

Abstract

We investigate the use of quantum-jump-based feedback to manipulate the stability of multipartite entangled dark states in an open quantum system. Using the model proposed in Phys. Rev. A 76, 010301(R) (2007) for a pair of atoms, we show a general strategy to produce many-body singlet stationary entangled states for larger number of atoms. In the case of four qubits, we propose a simple local feedback control that, although not optimal, is realistic and stabilises a highly entangled state. We discuss the limitations and analyse alternative strategies within the framework of direct jump feedback schemes.