Performance of Rotation-Symmetric Bosonic Codes in a Quantum Repeater Network

TL;DR

This paper evaluates the effectiveness of rotation-symmetric bosonic codes in quantum repeater networks, demonstrating their potential to improve communication distances and resource efficiency compared to traditional cat codes.

Contribution

It introduces and compares rotation-symmetric bosonic codes for quantum repeaters, analyzing their performance and resource requirements in quantum communication.

Findings

RSBCs outperform cat codes in secret key rate over certain distances

Fewer repeater stations are needed with RSBCs for the same key exchange distance

Resource overhead is reduced using RSBCs compared to traditional codes

Abstract

Quantum error correction codes based on continuous variables play an important role for the implementation of quantum communication systems. A natural application of such codes occurs within quantum repeater systems which are used to combat severe channel losses and local gate errors. In particular, channel loss drastically reduces the distance of communication between remote users. Here we consider a cavity-QED based repeater scheme to address the losses in the quantum channel. This repeater scheme relies on the transmission of a specific class of rotationally invariant error-correcting codes. We compare several rotation-symmetric bosonic codes (RSBCs) being used to encode the initial states of two remote users connected by a quantum repeater network against the convention of the cat codes and we quantify the performance of the system using the secret key rate. In particular, we determine the number of stations required to exchange a secret key over a fixed distance and establish the resource overhead.