Jul 22 – 25, 2019
ECT* - Villa Tambosi
Europe/Rome timezone
Abstracts submission open. Posters do not require abstract submission.

Wave amplification in rotating reference frames

Jul 22, 2019, 3:00 PM
30m
Meeting room (ECT* - Villa Tambosi)

Meeting room

ECT* - Villa Tambosi

Strada delle Tabarelle, 286 38123 - Villazzano (TN) Italy

Speaker

Prof. Daniele Faccio (University of Glasgow)

Description

Superradiant gain is the process in which waves are amplified via their interaction with a rotating body, examples including evaporation of a spinning black hole and electromagnetic emission from a rotating metal sphere.
We will first discuss the case of photon fluids, i.e. room temperature superfluids generated by a laser beam propagating in a nonlinear defocusing material. Prior work has already demonstrated the superfluid nature of the 2D beam profile in this setting and we have recently studied that by injecting a vortex pump beam, it is possible to generate a rotating spacetime metric and experimentally identify the horizon and ergosphere. Numerical studies based on the Nonlinear Schrodinger equation now illustrate the conditions under which experiments are expected to observe superradiance by analyzing the optical currents in the system.
Finally, we will examine a different scenario, more akin to the sutation examined in 1971 by Zel’dovich, i.e. a rotating cylinder. We elucidate theoretically how superradiance may be realized in the field of acoustics, and predict the possibility of non-reciprocally amplifying or absorbing acoustic beams carrying orbital angular momentum by propagating them through an absorbing medium that is rotating. We discuss a possible geometry for realizing the superradiant amplification process using existing technology.

Primary authors

Prof. Daniele Faccio (University of Glasgow) Dr Maria Chiara Braidotti

Presentation materials

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