06. September 2024

Our study on the dimensional crossover of a photon gas has been published Kiran's paper on the 1d-2D crossover is published

It is long known that the dimensionality of a system has great influence on the laws of physics. In one dimension, the Hohenberg-Mermin-Wagner theorem predicts that, under some constraints,  long-range order cannot be established in one dimension, as thermal fluctuations drive the system to an unordered situation. But what happens when going from two to one dimension? We have studied this crossover together with colleagues from the RPTU Kaiserslautern-Landau in a quantum gas of light.

Preparing the cavity
Preparing the cavity - Frank and Kirankumar fill the cavity with dye solution © Volker Lannert / Uni Bonn
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Using direct laser writing polymer structures were added to the surface of a dielectric mirror, which served as one of the mirrors in a microcavity. The polymer provides a parabolic potential for the photons in the microresonator, and by varying the aspect ratio one can tune the dimensionality of the system. By radiative contact to a dye solution the photons are cooled down, and one onserves a thermal population of photons within the eigenmodes of the resonator. In two dimensions we observe a phase transition to a Bose-Einstein condensate, which first softens and then completely vanishes when crossing to one dimension, while the photon gas is still quantum degenerate. Our study appears in Nature Physics. 

Additional Information:

Press release of the university

Nature Communities Blogpost

Homepage of the CRC/TR 185 "OSCAR"

Kirankumar Karkihalli Umesh, Julian Schulz, Julian Schmitt, Martin Weitz, Georg von Freymann, and Frank Vewinger
Dimensional crossover in a quantum gas of light
Nature Physics  (2024)
DOI: 10.1038/s41567-024-02641-7

Dr. Frank Vewinger
Institut für Angewandte Physik der Universität Bonn
Tel.: +49 228 733475
E-Mail: vewinger@iap.uni-bonn.de

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