Quantum Repeaters Using Continuous Variable Teleportation

TL;DR

This paper proposes a general quantum repeater protocol using continuous variable teleportation to mitigate loss effects in quantum optical communication, extending the feasible range of entanglement distribution.

Contribution

It introduces a novel, more universal quantum repeater approach applicable to continuous variable encodings, unlike previous discrete-only protocols.

Findings

Resource cost scales polynomially with distance

Protocol can extend entanglement distribution range

Implementation shows potential for practical improvements

Abstract

Quantum optical states are fragile and can become corrupted when passed through a lossy communication channel. Unlike for classical signals, optical amplifiers cannot be used to recover quantum signals. Quantum repeaters have been proposed as a way of reducing errors and hence increasing the range of quantum communications. Current protocols target specific discrete encodings, for example quantum bits encoded on the polarization of single photons. We introduce a more general approach that can reduce the effect of loss on any quantum optical encoding, including those based on continuous variables such as the field amplitudes. We show that in principle the protocol incurs a resource cost that scales polynomially with distance. We analyse the simplest implementation and find that whilst its range is limited it can still achieve useful improvements in the distance over which quantum entanglement of field amplitudes can be distributed.