Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 30: Matter At Low Temperature: Quantum Liquids, Bose-Einstein Condensates, Ultra-cold Atoms, ... 1

TT 30.1: Invited Talk

Wednesday, March 28, 2012, 15:00–15:30, H 3005

Bose-Einstein condensation of Photons — •Martin Weitz — Institut für Angewandte Physik, Universität Bonn, Wegelerstr. 8, D-53115 Bonn

Bose-Einstein condensation, the macroscopic ground state accumulation of particles with integer spin (bosons) at low temperature and high density, has been observed in several physical systems, including cold atomic gases and solid state physics quasiparticles. However, the most omnipresent Bose gas, blackbody radiation (radiation in thermal equilibrium with the cavity walls), does not show this phase transition. The photon number here is not conserved (vanishing chemical potential), and at low temperatures photons disappear in the cavity walls instead of occupying the cavity ground state. In my talk, I will describe an experiment observing a Bose-Einstein condensation of photons in a dye-filled microscopic optical resonator [1]. The phase transition to a macroscopically occupied ground state occurs at room temperature. In my talk, I will begin with a general introduction and give an account of current work and future plans of the Bonn photon gas experiment.
J. Klaers, J. Schmitt, F. Vewinger, and M. Weitz, Nature 468, 545 (2010).