Analog gravity by an optical vortex: Resonance enhancement of Hawking radiation

Abstract

Propagation of coherent light in a Kerr nonlinear medium can be mapped onto a flow of an equivalent fluid. Here we use this mapping to model the conditions in the vicinity of a rotating black hole as a Laguerre-Gauss vortex beam. We describe weak fluctuations of the phase and amplitude of the electric field by wave equations in curved space, with a metric that is similar to the Kerr metric. We find the positions of event horizons and ergoregion boundaries, and the conditions for the onset of superradiance, which are simultaneously the conditions for a resonance in the analogue Hawking radiation. The resonance strongly enhances the otherwise exponentially weak Hawking radiation at certain frequencies, and makes its experimental observation feasible.

Acoustic black-hole bombs and scalar clouds in a photon-fluid model

“…These systems are an ideal platform for analogue gravity investigations [32][33][34][35]. In particular, superradiant scattering in rotating photon-fluids has been theoretically demonstrated [36][37][38][39], and recently a rotating BH geometry has been experimentally realized [40].…”

Correspondence between dark energy quantum cosmology and Maxwell equations

“…Our proposal is in the same spirit than similar ones for analogue optical systems for quantum cosmologies [26,27], and for gravity in general (see for example Refs. [28][29][30][31]). However, our result establishes an optical analogue for a new kind of spinor quantized cosmological model.…”

Momentum correlations as signature of sonic Hawking radiation in Bose-Einstein condensates

“…With the normalization (12), this corresponds, for instance for a positive norm mode, to a perfect transmutation of an elementary excitation into a particle state which carries a unit current. For the "tilde Bogoliubov coefficients" (20), the prescription (31) yields…”

“…Many physical realizations have been proposed for observing analog Hawking radiation (see, e.g., [7][8][9][10][11][12]), among which the implementation of a sonic horizon in the flow of a Bose-Einstein condensate (BEC) rapidly appeared as quite promising [13]: the low temperature of the system and its paradigmatic quantum nature makes it an ideal playground for studying this phenomenon. However, a direct observation of the analogous sonic radiation in this system is still hindered by thermal effects and difficult to identify unambiguously.…”