Global Entanglement Distribution with Multi-mode Non-Gaussian Operations

TL;DR

This paper develops a new multi-mode photon catalysis framework and demonstrates its advantages over photon subtraction and addition for entanglement distribution in satellite-based quantum communication.

Contribution

It introduces the first multi-mode photon catalysis framework and applies it to enhance entanglement distribution in space-based continuous variable quantum systems.

Findings

Multi-mode photon catalysis outperforms photon subtraction and addition under certain conditions.

The framework is particularly effective at the transmitter with low initial squeezing.

At the receiver, it is superior when channel attenuation is high.

Abstract

Non-Gaussian operations have been studied intensively in recent years due to their ability to enhance the entanglement of quantum states. However, most previous studies on such operations are carried out in a single-mode setting, even though in reality any quantum state contains multi-mode components in frequency space. Whilst there have been general frameworks developed for multi-mode photon subtraction (PS) and photon addition (PA), an important gap exists in that no framework has thus far been developed for multi-mode photon catalysis (PC). In this work we close that gap. We then apply our newly developed PC framework to the problem of continuous variable (CV) entanglement distribution via quantum-enabled satellites. Due to the high pulse rate envisioned for such systems, multi-mode effects will be to the fore in space-based CV deployments. After determining the entanglement distribution possible via multi-mode PC, we then compare our results with the entanglement distribution possible using multi-mode PS and PA. Our results show that multi-mode PC carried out at the transmitter is the superior non-Gaussian operation when the initial squeezing is below some threshold. When carried out at the receiver, multi-mode PC is found to be the superior non-Gaussian operation when the mean channel attenuation is above some threshold. Our new results should prove valuable for next-generation deployments of CV quantum-enabled satellites.