Collective emission of light by dense atomic clouds: witnessing correlations and a phase transition by measuring photons
| Quand ? |
Le 12/12/2022, de 11:00 à 12:00 |
|---|---|
| Où ? | Salle Condorcet |
| Participants |
Igor Ferrier-Barbut |
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We study collective spontaneous emission by dense clouds of two-level atoms. The atoms are identically coupled to a mode of the electromagnetic field so that a photon in this mode is emitted collectively by the ensemble rather than individually by the atoms. In particular the power radiated collectively depends on the way the atomic dipoles are correlated. I will discuss our studies of the system's behaviour when continuously driven by a resonant laser that leads to a competition between laser driving and collective spontaneous emission. In a configuration that realizes a textbook model of a driven-dissipative many-body system, we observed that this competition induces a non-equilibrium phase transition between a magnetized phase and a steady-state superradiant phase.