Surface code quantum communication

TL;DR

This paper proposes a surface code quantum communication protocol that enables high-rate, long-distance quantum information transfer without two-way classical communication, given high-fidelity Bell pair generation with sufficient success probability.

Contribution

It introduces a surface code-based method for quantum communication that avoids two-way classical communication and achieves logarithmic resource scaling with distance under certain conditions.

Findings

High success probability (>0.65) and fidelity (>0.96) Bell pairs enable error-free long-distance communication.

Communication rate is limited only by local gate speed when conditions are met.

Logarithmic resource scaling is maintained even with lower success probabilities, given certain timing constraints.

Abstract

Quantum communication typically involves a linear chain of repeater stations, each capable of reliable local quantum computation and connected to their nearest neighbors by unreliable communication links. The communication rate in existing protocols is low as two-way classical communication is used. We show that, if Bell pairs are generated between neighboring stations with a probability of heralded success greater than 0.65 and fidelity greater than 0.96, two-way classical communication can be entirely avoided and quantum information can be sent over arbitrary distances with arbitrarily low error at a rate limited only by the local gate speed. The number of qubits per repeater scales logarithmically with the communication distance. If the probability of heralded success is less than 0.65 and Bell pairs between neighboring stations with fidelity no less than 0.92 are generated only every T_B seconds, the logarithmic resource scaling remains and the communication rate through N links is proportional to 1/(T_B log^2 N).