Relativistic effects in superradiance processes

O. N. Gadomskiĭ, V. R. Nagibarov, N. K. Solovarov

Wen-Te Liao, Sven Ahrens

P. I. Bardetskiı̆, N. A. Enaki

Y. D. Kim

F. De Martini, Ottavia Jedrkiewicz, Paolo Mataloni

The process of generation of non-classical radiation in an active Fabry-Perot dye microcavity, under femtosecond excitation, has been investigated. Single photon states, with a non-classical sub-Poissonian distribution have been generated after the excitation of a small number of active molecules, located between the two mirrors. By multiple excitation of the active medium, collective emission phenomena are expected because of the strong superradiant coupling occurring within the transverse coherence area of the microcavity. In particular, we have experimentally verified the principle of relativistic causality within the process of two-dipole superradiance by transverse interaction, in condition of strong microcavity confinement.

Luca Giacomelli, Iacopo Carusotto

We theoretically investigate superradiance effects in quantum field theories in curved space-times by proposing an analog model based on Bose-Einstein condensates subject to a synthetic vector potential. The breaking of the irrotationality constraint of superfluids allows us to study superradiance in simple planar geometries and obtain intuitive insight into the amplified scattering processes at ergosurfaces. When boundary conditions are modified to allow for reflections, dynamical instabilities are found, similar to the ones of ergoregions in rotating space-times. Their stabilization by horizons in black hole geometries is discussed. All these phenomena are reinterpreted through an exact mapping with the physics of one-dimensional relativistic charged scalar fields in electrostatic potentials. Our study provides a deeper understanding of the basic mechanisms of superradiance: By disentangling the different ingredients at play, it shines light on some misconceptions on the role of dissipation and horizons and on the competition between superradiant scattering and instabilities.