Heidelberg 2015 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 27: Quantum Gases: Bosons IV

Q 27.8: Vortrag

Dienstag, 24. März 2015, 16:15–16:30, P/H2

Calorimetry of a Bose condensed photon gas — •Tobias Damm, Julian Schmitt, Qi Liang, David Dung, Christian Wahl, Frank Vewinger, Martin Weitz, and Jan Klaers — Institut für Angewandte Physik, Universität Bonn, Wegelerstr. 8, D-53115 Bonn

In earlier works of our group, a thermalized photon gas and a transition to a Bose-Einstein condensate of photons has been realized in a dye-filled optical microcavity. A number-conserving thermalization of the photon gas in this system is achieved by repeated absorption and emission processes of dye-molecules.

The dye-filled optical microcavity environment is a well suited system to study the behavior of Bose gases at its phase transition from the classical Boltzmann regime to the condensed phase. Here we report on the measurement of calorimetric properties of a nearly ideal Bose gas at this transition, determined by investigating the thermodynamic behavior of the two-dimensional photon gas near criticality. The measurements clearly reveal a singularity of the specific heat, shaped similar to the well known λ-transition from the fluid to superfluid state of liquid helium.