# Resource reduction for distributed quantum information processing using quantum multiplexed photons

## TL;DR

This paper investigates the use of quantum multiplexed photons for loss mitigation in distributed quantum information processing, demonstrating resource-efficient quantum error correction with existing optical technology.

## Contribution

It introduces a novel approach using quantum multiplexing to reduce resources in quantum error correction for distributed systems, leveraging multi-qubit encoding in single photons.

## Key findings

- Quantum multiplexing reduces the number of single photon sources needed.
- The approach maintains or lowers the number of two-qubit gates required.
- Conventional optical gates suffice for implementing the proposed codes.

## Abstract

Distributed quantum information processing is based on the transmission of quantum data over lossy channels between quantum processing nodes. These nodes may be separated by a few microns or on planetary scale distances, but transmission losses due to absorption/scattering in the channel are the major source of error for most distributed quantum information tasks. Of course quantum error detection (QED) /correction (QEC) techniques can be used to mitigate such effects but error detection approaches have severe performance limitations due to the signaling constraints between nodes and so error correction approaches are preferable -assuming one has sufficient high quality local operations. Typically, performance comparisons between loss-mitigating codes assume one encoded qubit per photon. However single photons can carry more than one qubit of information and so our focus in this work is to explore whether loss-based QEC codes utilizing quantum multiplexed photons are viable and advantageous, especially as photon loss results in more than one qubit of information being lost. We show that quantum multiplexing enables significant resource reduction: in terms of the number of single photon sources while at the same time maintaining (or even lowering) the number of two-qubit gates required. Further, our multiplexing approach requires only conventional optical gates already necessary for the implementation of these codes.