Details

Autor(en) / Beteiligte

• Usuga, Mario A
• Müller, Christian R
• Andersen, Ulrik L
• Wittmann, Christoffer
• Marek, Petr
• Filip, Radim
• Marquardt, Christoph
• Leuchs, Gerd

Titel

Noise-powered probabilistic concentration of phase information

Ist Teil von

• Nature physics, 2010-10, Vol.6 (10), p.767-771

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2010

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Phase-insensitive optical amplification of an unknown quantum state is known to be a fundamentally noisy operation that inevitably adds noise to the amplified state. However, this fundamental noise penalty in amplification can be circumvented by resorting to a probabilistic scheme as recently proposed and demonstrated in refs 6, 7, 8. These amplifiers are based on highly non-classical resources in a complex interferometer. Here we demonstrate a probabilistic quantum amplifier beating the fundamental quantum limit using a thermal-noise source and a photon-number-subtraction scheme. The experiment shows, surprisingly, that the addition of incoherent noise leads to a noiselessly amplified output state with a phase uncertainty below the uncertainty of the state before amplification. This amplifier might become a valuable quantum tool in future quantum metrological schemes and quantum communication protocols.