Near-term performance of quantum repeaters with imperfect ensemble-based quantum memories

TL;DR

This paper evaluates the near-term feasibility of quantum repeater protocols using imperfect ensemble-based quantum memories, considering various implementations and efficiency decay, and finds that current technology can enable proof-of-principle demonstrations.

Contribution

It provides a detailed analysis of quantum repeater performance with realistic, imperfect memories and offers practical guidance for near-term experimental implementations.

Findings

Quantum repeater demonstrations are feasible with current technology.

Memory efficiencies decay exponentially, impacting repeater rates.

Multiple implementation platforms are analyzed for practical deployment.

Abstract

We study the feasibility of meaningful proof-of-principle demonstrations of several quantum repeater protocols with photon (single-photon and photon-pair) sources and atomic-ensemble based quantum memories. We take into account non-unit memory efficiencies that decay exponentially with time, which complicates the calculation of repeater rates. We discuss implementations based on quantum dots, parametric down-conversion, rare-earth-ion doped crystals, and Rydberg atoms. Our results provide guidance for the near-term implementation of long-distance quantum repeater demonstrations, suggesting that such demonstrations are within reach of current technology.