Speaker: Maxime Richard
Title: Elementary excitations in a quantum fluid of light
Abstract: Exciton polaritons in semiconductor microcavities can be envisaged as photons trapped within the cavity spacer and interacting with each other. A non-trivial quantum fluid of light can thus be formed by resonant laser excitation of polaritons, in which a wealth of quantum many-body phenomena, such as superfluidity, have been reported. The underlying mechanism governing them is embedded in polariton two-body interactions, which leads to Bogoliubov elementary excitation of the condensate. Bogoliubov excitations have a hybrid density–phase nature which is different from the free particles and which is essential in understanding these phenomena. In this presentation, I will review our recent works on the experimental evidence and characterisation of Bogoliubov excitations forming on top of a resonantly driven polariton condensate, and on the influence of the solid-state environment that can lead, for instance, to speed of sound renormalisation or help probe a novel thermal decoupling mechanism.
Bio: EQUS AI Richard and his co-workers from French National Centre for Scientific Research (CNRS) are collaborating with CI Volz group on the quantum engines and instruments program in the domain of light–matter–phonon interactions in semiconductor nanosystems. Specifically, they have been collaborating on non-equilibrium thermodynamics of polariton quantum fluids and optomechanics with levitated objects in the light–matter strong-coupling regime.
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