Hannover 2016 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 29: Quantum Gases: Bosons III
Q 29.7: Vortrag
Mittwoch, 2. März 2016, 12:45–13:00, e001
Phase and number correlations of Bose-Einstein-condensed light in a dye microcavity — •Julian Schmitt1, Tobias Damm1, David Dung1, Christian Wahl1, Frank Vewinger1, Jan Klaers2, and Martin Weitz1 — 1Institut für Angewandte Physik, Universität Bonn, Wegelerstraße 8, 53115 Bonn — 2Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, 8093 Zürich
Large statistical number fluctuations are a fundamental property known from the thermal behaviour of bosons, as has been revealed for both photons and material particles. In contrast to incoherent thermal ensembles, Bose-Einstein condensates can show both long-range phase coherence as well as damped intensity fluctuations. By examining the temporal interference of a Bose-Einstein condensate of photons in a dye microcavity, we observe the phase evolution and the emergence of temporal coherence of the photon condensate. In a Hanbury Brown-Twiss experiment, we identify a regime with large statistical intensity fluctuations, which are a consequence of grand-canonical statistical conditions realized by the photo-excitable dye molecules constituting both a particle and a heat reservoir. For small condensate sizes, we observe phase jumps of the condensate attributed to spontaneous symmetry breaking following condensate fluctuations to small photon numbers. For large systems, our experimental data shows phase coherence even in the presence of statistical number fluctuations. More recently, we have focussed on the study of the spatio-temporal correlations of the photon gas both in the thermal and the condensed phase.