Session
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TOM8 S02: Nonlinear and Quantum Optics 2
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Presentations
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2:30pm - 3:00pm
Invited ID: 162 / TOM8 S02: 1 TOM 8 Non-linear and Quantum Optics Superfluid light through dissipation
Light in a nonlinear cavity is expected to flow without friction - like a superfluid - under certain conditions. Until now, part-light part-matter (i.e., polariton) superfluids have been observed either at liquid helium temperatures in steady state, or at room temperature for sub-picosecond timescales. Here we report superfluid cavity photons (not polaritons) for the first time. When launching a photon fluid against a defect, we observe a suppression of backscattering above a critical density and below a critical velocity. Room-temperature and steady-state photon superfluidity emerges thanks to the strong thermo-optical nonlinearity of our oil-filled cavity. Surprisingly, dissipationless superfluid flow is achieved by absorptive dissipation inducing the thermal nonlinearity. We also show how the thermal relaxation of the oil sets the timescale at which superfluidity emerges. Our experimental observations are reproduced qualitatively by numerical calculations based on a generalized Gross-Pitaevskii equation for photons coupled to a thermal field. The interpretation of superfluid photons is further substantiated by phase dislocations appearing in the wake of a defect at the breakdown of superfluidity. Our results establish thermo-optical nonlinear cavities as platforms for probing photon superfluidity at room temperature, and offer perspectives for exploring superfluidity in arbitrary potential landscapes using structured mirrors. 3:00pm - 3:30pm
Invited ID: 115 / TOM8 S02: 2 TOM 8 Non-linear and Quantum Optics Quantum vacuum excitation of a quasi-normal mode in an analog model of black hole spacetime CNRS, France Vacuum quantum fluctuations near horizons are known to yield correlated emission by the Hawking effect. In this talk, I will explain how a 1 dimensional flow of microcavity polaritons may be engineered to produce an effective curved spacetime with a black hole horizon. I will present numerical computations of correlated emission on this spacetime and show that, in addition to the Hawking effect at the sonic horizon, quantum fluctuations may result in a sizeable stationary excitation of a quasi-normal mode of the field theory. Observable signatures of the excitation of the quasi-normal mode are found in the spatial density fluctuations as well as in the spectrum of Hawking emission. I will explain how the driven-dissipative dynamics of the polariton fluid are key to observing the quantum excitation of the quasi-normal mode. Nonetheless, this observation suggests a general and intrinsic fluctuation-driven mechanism leading to the quantum excitation of quasi-normal modes on black hole spacetimes. 3:30pm - 3:45pm
ID: 116 / TOM8 S02: 3 TOM 8 Non-linear and Quantum Optics Paraxial quantum fluids light in hot atomic vapors LKB, France Hot atomic vapors are widely used in non-linear and quantum optics due to their large Kerr non-linearity. This non-linearity induces effective photon-photon interactions allowing light to behave as a fluid displaying quantum properties such as superfluidity. In this presentation, I will show that we have full control over the Hamiltonian that drives the system and that we can engineer an analogue simulator with light. 3:45pm - 4:00pm
ID: 394 / TOM8 S02: 4 Post Deadline submission Photonic Maxwell's demon: feed-forward methods for photonic thermodynamic tasks Laboratoire Kastler Brossel, CNRS, France Maxwell's Demon is at the heart of the interrelation between quantum information processing and thermodynamics. In this thought experiment, a demon extracts work from two thermal baths at equilibrium by gaining information about them at the single-particle level and applying classical feed-forward operations. In this talk I will show how to implement a photonic version of Maxwell's Demon with active feed-forward in a fiber-based system using ultrafast optical switches. This is the first realisation of an active Demon. The experiment shows that, if correlations exist between the two thermal baths, the Demon can extract over an order of magnitude more work than without correlations. This demonstrates the great potential of photonic experiments -- which provide a unique degree of control on the system -- to access new regimes in quantum thermodynamics. |