Multiplexed Quantum Communication with Surface and Hypergraph Product Codes

TL;DR

This paper investigates how quantum multiplexing affects logical error rates in surface and hypergraph product codes, demonstrating that strategic qubit-photon assignment can reduce errors and improve quantum communication efficiency.

Contribution

It introduces methods to optimize multiplexed quantum codes, showing how to minimize loss errors and encode higher-distance codes with fewer photons.

Findings

Multiplexing increases the impact of loss errors but can be mitigated.

Intelligent qubit-photon assignment reduces logical error rates.

Higher-distance codes can be encoded in fewer photons, lowering overall errors.

Abstract

Connecting multiple processors via quantum interconnect technologies could help overcome scalability issues in single-processor quantum computers. Transmission via these interconnects can be performed more efficiently using quantum multiplexing, where information is encoded in high-dimensional photonic degrees of freedom. We explore the effects of multiplexing on logical error rates in surface codes and hypergraph product codes. We show that, although multiplexing makes loss errors more damaging, assigning qubits to photons in an intelligent manner can minimize these effects, and the ability to encode higher-distance codes in a smaller number of photons can result in overall lower logical error rates. This multiplexing technique can also be adapted to quantum communication and multimode quantum memory with high-dimensional qudit systems.