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MO: Fachverband Molekülphysik

MO 16: In Memoriam of Hermann Haken (joint session Q/MO)

MO 16.3: Hauptvortrag

Mittwoch, 12. März 2025, 12:00–12:30, HS I PI

Photons in a dye-filled cavity: quantum-optical system interpolating between Bose-Einstein condensates and laser-like states — •Milan Radonjić — Universität Hamburg, Germany — University of Belgrade, Serbia

It is well known that photons in a dye-filled cavity exhibit a Bose-Einstein condensate (BEC) of light [1]. We generalize the microscopic non-equilibrium Kirton-Keeling model [2] of such a system by carefully considering the interplay of coherent and dissipative dynamics within the Lindblad master equation framework pioneered by Hermann Haken in his theory of lasers [3]. The resulting equations of motion of both photonic and matter degrees of freedom are then used to study the steady-state properties of the system. We demonstrate that this system can interpolate between photon BEC and laser-like states, depending on whether the dissipative or coherent influence of the environment is dominant [4]. In the former case, we show that the cavity modes of different energies are essentially uncorrelated. In the laser-like regime, some cavity mode acquires macroscopic occupation, while the populations of other cavity levels strongly deviate from the Bose-Einstein distribution. Additionally, the steady state contains a rather high degree of correlations between the different cavity modes.

[1] J. Klaers et al., Nature 468, 545 (2010).

[2] P. Kirton and J. Keeling, Phys. Rev. Lett. 111, 100404 (2013).

[1] H. Haken, Laser Theory, Springer (1970, 1984).

[4] M. Radonjić et al., New J. Phys. 20, 055014 (2018).

Keywords: Bose-Einstein condensate; Condensate of light; Laser theory; Lindblad master equation; Dye-filled cavity