Colloquia

One of the striking differences between the classical world and the quantum world is the measurement process. This opens interesting possibilities to study how a quantum system evolves after a measurement. We have implemented a cavity QED system, where an atom or a few atoms interact with a single mode of the electromagnetic field. This interaction is such that a quantum fluctuation, the emission of a single photon, is a large event. We are studying, by conditional measurements, the dynamics of the cavity QED system as it returns to steady state after a fluctuation and can now relate this to some of its intrinsic properties such as entanglement.