Implementation of a non-deterministic optical noiseless amplifier

Franck Ferreyrol (1) , Marco Barbieri (1) , Rémi Blandino (1) , Simon Fossier (1) , Rosa Tualle-Brouri (1) , Philippe Grangier (1)

1 Laboratoire Charles Fabry de l'Institut d'Optique / Optique quantique

Quantum mechanics imposes that any amplifier that works independently on the phase of the input signal has to introduce some excess noise. The impossibility of such a noiseless amplifier is rooted into unitarity and linearity of quantum evolution. A possible way to circumvent this limitation is to interrupt such evolution via a measurement, providing a random outcome able to herald a successful - and noiseless - amplification event. Here we show a successful realisation of such an approach; we perform a full characterization of an amplified coherent state using quantum homodyne tomography, and observe a strong heralded amplification, with about 6dB gain and a noise level significantly smaller than the minimal allowed for any ordinary phase-independent device.

Domains: Quantum Physics [quant-ph]

Franck Ferreyrol, Marco Barbieri, Rémi Blandino, Simon Fossier, Rosa Tualle-Brouri, et al.. Implementation of a non-deterministic optical noiseless amplifier. Physical Review Letters, 2010, 104, pp.123603. ⟨10.1103/PhysRevLett.104.123603⟩. ⟨hal-00553571⟩