Aula Conversi (Dip. di Fisica - Edificio G.Marconi)
Aula Conversi
Dip. di Fisica - Edificio G.Marconi
Description
Bose-Einstein condensation, the macroscopic ground state occupation of a system of bosonic particles below a critical temperature, has been observed in cold atomic gases and solid-state physics quasiparticles. In contrast, photons do not show this phase transition usually, because in Plancks blackbody radiation the particle number is not conserved and at low temperature the photons disappear in the walls of the system. I will describe an experiment realizing a photon Bose-Einstein condensate in a dye-filled optical microcavity, which acts as a white-wall photon box. The cavity mirrors provide a trapping potential and a non-vanishing ef! fective photon mass, making the system formally equivalent to a two-dimensional gas of trapped massive bosons. Thermalization of the photon gas is reached in a number conserving way by repeated absorption-emission cycles in the dye molecules. 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.
