# Memory-based Probabilistic Noiseless Amplification of Coherent states

## TL;DR

This paper proposes a probabilistic method for noiseless amplification of weak coherent states using atomic ensembles and photon detection, leveraging collective atomic excitations for quantum state enhancement.

## Contribution

It introduces a novel approach combining atomic ensemble interactions and photon detection to achieve noiseless amplification of coherent states.

## Key findings

- Amplification achieved via detection of scattered photons in atomic ensembles.
- Identification of failure events during the amplification process.
- Analytical demonstration of the amplification mechanism.

## Abstract

We analytically show that probabilistic amplification of a weak coherent state stored inside an atomic medium can be achieved via detection of coherently scattered photons. We show that this is because of collective excitations created among atoms in the ensemble. We describe the physics of the amplification and identify the failure events, which occur during the amplification process. The amplification is realized by coherently mapping a weak coherent state in an ensemble of $\Lambda$-level atoms followed by detection of multiple Raman scattered photons, conditionally projecting the coherent state into an amplified state upon retrieval.