Quantum repeaters and computation by a single module

TL;DR

This paper introduces a simple, single-module protocol for remote nondestructive parity measurement that enables efficient quantum communication and computation tasks, including entanglement generation and cluster state creation.

Contribution

The authors propose a novel, practical RNPM protocol using basic optical devices, improving quantum repeater efficiency and enabling scalable quantum communication and measurement-based quantum computing.

Findings

Quantum repeater with sub-exponential scaling of communication time

Protocol achieves key operations with simple optical components

Potential for generating cluster states with reduced internal losses

Abstract

We present a protocol of remote nondestructive parity measurement (RNPM) on a pair of quantum memories. The protocol works as a single module for key operations such as entanglement generation, Bell measurement, parity check measurement, and an elementary gate for extending one-dimensional cluster states. The RNPM protocol is achieved by a simple combination of devices such as lasers, optical fibers, beam splitters, and photon detectors. Despite its simplicity, a quantum repeater composed of RNPM protocols is shown to have a communication time that scales sub-exponentially with the channel length, and it can be further equipped with entanglement distillation. With a reduction in the internal losses, the RNPM protocol can also be used for generating cluster states toward measurement-based quantum communication.