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Michel BRUNE

Exploring quantum measurement and decoherence with trapped photons

We present experiments where photons are trapped in a nearly ideal “photon box”, as Einstein and Bohr proposed in one of the gedanken experiments to show the unbelievable strangeness of the quantum theory. Our photon box consists of a low-energy-loss cavity, where microwave photons are trapped between superconducting mirrors.


In these experiments, we are able to probe and manipulate the trapped field using single Rydberg atoms, which act as extremely sensitive and non-destructive probes. We will show how this system can be used for exploring the most fundamental aspects of the theory of quantum measurement, such as state-collapse or the occurrence of quantum jumps in a quantum dynamics. We will also address the problem of the relation between the quantum behaviour of small isolated systems and the classical behaviour of the measurement apparatus by preparing a “Schrödinger kitten” state of the field and observing its decoherence.




Michel BRUNE was born in 1964. He obtained his Ph. D. in 1988 at the Ecole Normale Supérieure (ENS) under the supervision of S. Haroche, and his habilitation in 2001. He is director of research at the CNRS, professor at Ecole Polytecnique and he presently works at the Laboratoire Kastler Brossel, ENS. He is also director of the master "Fundamental Concepts of Physics" which is shared by the ENS, Ecole Polytechnique, Université Pierre et Marie Curie and the Université Paris Sud.


M. Brune has received several prizes :

- Price "Joung researcher" (1994), of DRET.

- "Grand prix Ampère de l’électricité de France", of french accademy of science (1998), shared with J.M. Raimond.

- "Fabry-de-Gramont price", (2001) of the french optical society.