Low-Noise Amplification of a Continuous Variable Quantum State

TL;DR

This paper reports an experimental realization of a low-noise, phase-insensitive optical amplifier using four-wave mixing in hot Rb vapor, achieving near-quantum-limited performance and enabling quantum cloning while preserving entanglement.

Contribution

It introduces a practical, low-noise optical amplifier based on four-wave mixing that operates near the quantum limit and can clone entangled states.

Findings

Achieved near-quantum-limited amplification performance.

Demonstrated cloning of one mode of a two-mode squeezed state.

Preserved entanglement during amplification and cloning.

Abstract

We present an experimental realization of a low-noise, phase-insensitive optical amplifier using a four-wave mixing interaction in hot Rb vapor. Performance near the quantum limit for a range of amplifier gains, including near unity, can be achieved. Such low-noise amplifiers are essential for so-called quantum cloning machines and are useful in quantum information protocols. We demonstrate that amplification and ``cloning'' of one half of a two-mode squeezed state is possible while preserving entanglement.