Noiseless linear amplification via weak measurements

TL;DR

This paper explores how weak measurements can approximate noiseless linear amplification in quantum systems, enabling applications like entanglement concentration and probabilistic cloning, despite the operation's inherent probabilistic nature.

Contribution

It introduces a method to approximate noiseless linear amplification using weak measurements, expanding the toolkit for quantum information processing.

Findings

Weak measurements can approximate noiseless amplification.

Probabilistic cloning of weak coherent states is feasible.

The scheme has potential applications in quantum repeaters.

Abstract

We discuss the recently introduced concept of non-deterministic noiseless linear amplification, demonstrating that such an operation can only be performed perfectly with vanishing probability of success. We show that a weak measurement, which imprints the weak value of an observable of a pre-selected and post-selected system onto a probe system, can be used to approximate probabilistic noiseless amplification. This result may be applied to various tasks in continuous variable quantum information, including entanglement concentration, probabilistic cloning, and in quantum repeaters. We discuss the application of our scheme to probabilistic cloning of weak coherent states.