Light particles reveal critical scaling in a two-dimensional photon gas
A team of researchers from the University of Bonn, Heidelberg University and the National Autonomous University of Mexico has studied the critical behavior of light particles (photons) close to a phase transition. This critical scaling behavior, which sees thermodynamic quantities grow extremely large or diverge shortly prior to Bose-Einstein condensation, had never before been seen in photon…
Researchers from the University of Bonn, Heidelberg University and the National Autonomous University of Mexico have observed critical scaling in a two-dimensional photon gas, a phenomenon that had not been seen before in photon gases. This critical scaling behavior, characterized by a rapid increase in thermodynamic quantities near Bose-Einstein condensation, was studied by trapping light particles in a mirror box within an optical microresonator filled with a dye solution.
By measuring the spatial correlations of the nearly non-interacting photons as they cooled down and thermalized, the team was able to determine the critical exponent—a value describing the correlation length's increase as temperature changes. The researchers found that photon gases exhibit a distinct universality class of physical systems, with spatial correlations that rapidly increase and diverge prior to condensation.
This discovery fills a significant gap in the study of phase transitions and may lead to new research avenues for systems outside thermal equilibrium, as well as potential applications in optics.
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