Experimental on-demand recovery of entanglement by local operations within non-Markovian dynamics

TL;DR

This paper demonstrates on-demand entanglement recovery in non-Markovian quantum systems using local operations, through two optical experiments implementing open-loop and closed-loop control schemes, enhancing quantum network efficiency.

Contribution

It introduces practical local control schemes for entanglement restoration in non-Markovian dynamics, showing on-demand recovery without global operations.

Findings

Entanglement can be restored on-demand using local operations.

Both open-loop and closed-loop schemes improve entanglement sharing.

Experimental validation in all-optical setups confirms the approach.

Abstract

In many applications entanglement must be distributed through noisy communication channels that unavoidably degrade it. Entanglement cannot be generated by local operations and classical communication (LOCC), implying that once it has been distributed it is not possible to recreate it by LOCC. Recovery of entanglement by purely local control is however not forbidden in the presence of non-Markovian dynamics, and here we demonstrate in two all-optical experiments that such entanglement restoration can even be achieved on-demand. First, we implement an open-loop control scheme based on a purely local operation, without acquiring any information on the environment; then, we use a closed-loop scheme in which the environment is measured, the outcome controling the local operations on the system. The restored entanglement is a manifestation of "hidden" quantum correlations resumed by the local control. Relying on local control, both schemes improve the efficiency of entanglement sharing in distributed quantum networks.