Low-Noise Amplification of a Continuous-Variable Quantum State
Raphael C. Pooser, Alberto M. Marino, Vincent Boyer, Kevin M. Jones, Paul D. Lett · Physical Review Letters · 2009
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.