The Scientific Computing Laboratory seminar will be held on Friday, 25 December 2015 at 14:00 in the library reading room of the Institute of Physics Belgrade. The talk entitled

"Microscopic model of photon condensation"

will be given by Dr. Milan Radonjić (Photonics Center, Institute of Physics Belgrade and Faculty of Physics, University of Vienna).

Abstract of the talk:  
Convincing evidence of macroscopic occupation of the lowest mode for a gas of photons confined in a dye-filled optical microcavity has been first presented in a seminal experiment in Bonn [1] and recently also in London [2]. Thermal relaxation of the dye molecules due to interaction with the solvent gives rise to Bose-Einstein distribution of the microcavity photons in the experiment. These equilibrium properties could recently be understood within the framework of a non-equilibrium description [3,4]. We will critically analyze and extend this description by including coherent coupling of dye molecules and microcavity photons, influenced by the solvent, in addition to dissipative coupling that leads to the thermalization. Interestingly, our preliminary results indicate that the strong interaction of the dye molecules with the solvent favors the thermalization dynamics and makes possible Bose-Einstein condensation of photons. On the other hand, weak solvent influence promotes the coherent dynamics and enables the formation of laser-like state. Depending on the values of experimental parameters different optical cavity modes may become macroscopically occupied. The onset of the latter behavior has recently been noticed in a simplistic two-mode laser model [5] that can be seen as a minimalistic precursor of the detailed model of photon condensation.

References

[1] J. Klaers, J. Schmitt, F. Vewinger, and M. Weitz, Nature (London) 468, 545 (2010).
[2] J. Marelic and R. A. Nyman, Phys. Rev. A 91, 033813 (2015).
[3] P. Kirton and J. Keeling, Phys. Rev. Lett. 111, 100404 (2013).
[4] P. Kirton and J. Keeling, Phys. Rev. A 91, 033826 (2015).
[5] W. Kopylov, M. Radonjić, T. Brandes, A. Balaž, and A. Pelster, Phys. Rev. A 92, 063832 (2015).