Theoretical Analysis of an Ideal Noiseless Linear Amplifier for Einstein-Podolsky-Rosen Entanglement Distillation

TL;DR

This paper provides a theoretical analysis of a noiseless linear amplifier based on quantum scissors, focusing on its ability to distill entanglement after lossy transmission, and compares single and multi-stage configurations for weakly excited states.

Contribution

It offers a detailed theoretical evaluation of the performance of noiseless linear amplifiers for entanglement distillation, including the impact of multiple amplification stages.

Findings

Amplifiers can effectively increase entanglement after lossy channels.

Limited stages may be more practical and advantageous.

Performance depends on measures like entanglement and purity.

Abstract

We study the operational regime of a noiseless linear amplifier based on quantum scissors that can nondeterministically amplify the one photon component of a quantum state with weak excitation. It has been shown that an arbitrarily large quantum state can be amplified by first splitting it into weak excitation states using a network of beamsplitters. The output states of the network can then be coherently recombined. In this paper, we analyse the performance of such a device for distilling entanglement after transmission through a lossy quantum channel, and look at two measures to determine the efficacy of the noiseless linear amplifier. The measures used are the amount of entanglement achievable and the final purity of the output amplified entangled state. We study the performances of both a single and a two-element noiseless linear amplifier for amplifying weakly excited states. Practically, we show that it may be advantageous to work with a limited number of stages.