Entangling remote microwave quantum computers with hybrid entanglement swap and variational distillation

TL;DR

This paper introduces a practical protocol for distributing entanglement between remote microwave quantum computers using optical-microwave entanglement, significantly improving rate and fidelity with near-term feasible technology.

Contribution

It proposes a hybrid entanglement-swap and variational distillation protocol that enhances remote microwave entanglement distribution efficiency and robustness.

Findings

Boosts entanglement distribution rate by two orders of magnitude.

Provides a robust protocol against optical loss and noise.

Enables practical quantum links for superconducting microwave quantum computers.

Abstract

Superconducting microwave circuits with Josephson junctions are a major platform for quantum computing. To unleash their full capabilities, the cooperative operation of multiple microwave superconducting circuits is required. Therefore, designing an efficient protocol to distribute microwave entanglement remotely becomes a crucial open problem. Here, we propose a continuous-variable entanglement-swap approach based on optical-microwave entanglement generation, which can boost the ultimate rate by two orders of magnitude at state-of-the-art parameter region, compared with traditional approaches. We further empower the protocol with a hybrid variational entanglement distillation component to provide huge advantage in the infidelity-versus-success-probability trade-off. Our protocol can be realized with near-term device performance, and is robust against non-perfections such as optical loss and noise. Therefore, our work provides a practical method to realize efficient quantum links for superconducting microwave quantum computers.