We have proposed and experimentally tested a general definition for the nonclassicality of a quantum optical process based on its action on coherent light states.

# Category: Quantum Optics

Aug 01 2012

## Adaptively probing the shape of quantum light

We describe the first use of a genetic algorithm to adaptively probe the arbitrary spectral/temporal shape of ultrashort quantum light states. Besides fully reconstructing the complex spectral/temporal structure of a single photon, we also demonstrate how to use this capability as a clever new way of encoding quantum information.

Jan 01 2011

## A hi-fi noiseless amplifier for quantum light states

We have demonstrated the operation of a non-deterministic noiseless amplifier based on the addition and subtraction of single photons. Our scheme greatly outperforms all other existing approaches to phase-insensitive noiseless amplification, both in terms of amplification gain and final state fidelity.

Oct 18 2009

## First direct test of quantum commutation rules

Arbitrary superpositions of quantum operators demonstrated: first direct quantitative test of quantum commutation rules. We designed a scheme for conditionally generating arbitrary coherent superpositions of quantum operators. The general scheme was later applied to an experiment for implementing the commutator of the creation and annihilation operators. We quantitatively verified the well-known commutation rules in a …

Dec 18 2008

## Playing with photon subtraction

We implemented a reliable scheme for single photon subtraction and tested its effects on paradigmatic light states: Fock, thermal, and coherent. When applied to coherent states, the annihilation operator does not modify the state itself. Experimentally verified that coherent states are eigenstates of the photon annihilation operator.

Sep 23 2008

## Cavity-enhanced generation of highly-nonclassical states

We use a pulsed pump enhancement cavity to produce highly-nonclassical states of light at high repetition rates. The frequency comb structure of the pump laser may be transferred to the produced quantum light.

Aug 01 2008

## To the roots of non-classicality: First reconstruction of a non-classical Glauber-Sudarshan P-function

We performed the first reconstruction of a non-classical P-function for a photon-added thermal light state. This is the first demonstration of non-classicality according to the original definition by R. Glauber.

Sep 23 2007

## Direct experimental test of quantum non-commutativity by single photon creation and annihilation

We have implemented simple sequences of photon addition and subtraction to/from a light field. By verifying the difference in the final states when using the two operators in reverse order, we provide the first direct test of quantum commutation rules.

Oct 23 2006

## Single-photon remote temporal delocalization and violation of a Bell’s type inequality

We have remotely delocalized a single photon onto two distinct and widely separated temporal modes. The tomographic analysis of the two-mode homodyne data has allowed us to prove (under some assumptions) the violation of a form of Bell’s inequality.

Oct 23 2004

## First experimental photon addition

First realization of single-photon-added coherent states. We have generated and analyzed novel states of light that continuously change their character from fully quantum to fully classical.