On-demand quantum state transfer and entanglement between remote microwave cavity memories

TL;DR

This paper demonstrates rapid, on-demand quantum state transfer and entanglement generation between remote superconducting microwave cavities, advancing modular quantum computing with high fidelity and error mitigation techniques.

Contribution

It introduces a method for deterministic quantum state transfer and remote entanglement between superconducting cavities using traveling microwave photons, with error heralding and quantum error correction.

Findings

Quantum state transfer fidelity of 76%, improved to 87% with heralding.

Remote entanglement generation rate exceeds photon loss by over three times.

Transfer of quantum error correction code words enabling deterministic photon loss mitigation.

Abstract

Modular quantum computing architectures require fast and efficient distribution of quantum information through propagating signals. Here we report rapid, on-demand quantum state transfer between two remote superconducting cavity quantum memories through traveling microwave photons. We demonstrate a quantum communication channel by deterministic transfer of quantum bits with 76% fidelity. Heralding on errors induced by experimental imperfection can improve this to 87% with a success probability of 0.87. By partial transfer of a microwave photon, we generate remote entanglement at a rate that exceeds photon loss in either memory by more than a factor of three. We further show the transfer of quantum error correction code words that will allow deterministic mitigation of photon loss. These results pave the way for scaling superconducting quantum devices through modular quantum networks.