Optimal architecture for a non-deterministic noiseless linear amplifier

TL;DR

This paper introduces an optimal theoretical model for non-deterministic noiseless linear amplifiers that achieves the maximum success probability, enhancing quantum communication tasks like key distribution and channel purification.

Contribution

It develops a theoretical model that reaches the fundamental success probability limit for noiseless linear amplification, improving upon previous linear optics and photon counting designs.

Findings

Model reaches the theoretical success probability bound

Calculates fidelity and success probability for coherent states

Analyzes performance with EPR entangled states

Abstract

Non-deterministic quantum noiseless linear amplifiers are a new technology with interest in both fundamental understanding and new applications. With a noiseless linear amplifier it is possible to perform tasks such as improving the performance of quantum key distribution and purifying lossy channels. Previous designs for noiseless linear amplifiers involving linear optics and photon counting are non-optimal because they have a probability of success lower than the theoretical bound given by the theory of generalised quantum measurement. This paper develops a theoretical model which reaches this limit. We calculate the fidelity and probability of success of this new model for coherent states and Einstein-Podolsky-Rosen (EPR) entangled states.