# Remote entanglement stabilization and distillation by quantum reservoir engineering

## TL;DR

This paper demonstrates autonomous protocols for stabilizing and distilling entanglement between distant superconducting qubits using reservoir engineering with a three-wave mixing device, enabling robust entanglement in quantum networks.

## Contribution

It introduces a novel autonomous entanglement stabilization and distillation method for remote qubits via reservoir engineering with a three-wave mixer.

## Key findings

- Weakly-squeezed states can stabilize maximally entangled Bell states.
- Protocols are robust against qubit-cavity asymmetries and losses.
- Remote entanglement can be maintained and distilled autonomously.

## Abstract

Quantum information processing in a modular architecture requires the distribution, stabilization and distillation of entanglement in a qubit network. We present autonomous entanglement stabilization protocols between two superconducting qubits that are coupled to distant cavities. The coupling between cavities is mediated and controlled via a three-wave mixing device that generates either a two-mode squeezed state or a delocalized mode between the remote cavities depending on the pump applied to the mixer. Local drives on the qubits and the cavities steer and maintain the system to the desired qubit Bell state. Most spectacularly, even a weakly-squeezed state can stabilize a maximally entangled Bell state of two distant qubits through an autonomous distillation process. Moreover, we show that such reservoir-engineering based protocols can stabilize entanglement in presence of qubit-cavity asymmetries and losses.