Par Simon Pigeon, Laboratoire Kastler Brossel, Paris
Mardi 3 Juillet, 14h00, Salle des séminaires (215), 2ème étage, Bâtiment A4N
Light is a fascinating phenomenon. It has been since the beginning of the XXth century described as a gas of non-interacting particles: photons. Confined between two mirrors in a cavity, photons acquire an effective mass and, due to imperfect mirrors a finite lifetime. Con- sequently, this gas exchanges constantly with its environment through dissipation. Based on methods borrowed from both open quantum system and statistical physics, the thermodynamics of these exchanges can be resolved to reveal its true stochastic nature as I will present in a first part . This allows, behind others, to the definition of fluctuation theorem . Moreover, me- diated light-matter interaction, effective photon interaction can be engineered. In this context, cavity light behaves as a fluid and surprisingly as a quantum fluid . In a second part, I will explore this hydrodynamical analogy illustrating how the underlying driven-dissipative nature of quantum fluids of light modifies their properties as well as the topological excitations that may form in them .
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 S. Pigeon, L. Fusco, A. Xuereb, G. De Chiara and M. Paternostro. “Thermodynamics of trajectories and local fluctuation theorems for harmonic quantum networks,” New J. Phys. 18 013009 (2016).
 A. Amo, S. Pigeon, D. Sanvitto, V. G. Sala, R. Hivet, I. Carusotto, F. Pisanello, G. Leménager, R. Houdré, E. Giacobino, C. Ciuti and A. Bramati, “Polariton superfluids reveal quantum hydrodynamic solitons,” Science 332 1167 (2011).
 S. Pigeon and A. Bramati, “Sustained propagation and topological excitation control in polariton superfluid,” New J. Phys. 19 095004 (2017)