Numerical study of a recent black-hole lasing experiment

We theoretically analyse a recent experiment reporting the observation of a self-amplifying Hawking radiation in a flowing atomic condensate (Steinhauer J., Nat. Phys., 10 (2014) 864). We are able to accurately reproduce the experimental observations using a theoretical model based on the numerical solution of a mean-field Gross-Pitaevskii equation that does not include quantum fluctuations of the matter field. In addition to confirming the black-hole lasing mechanism, our results show that the underlying dynamical instability has a classical hydrodynamic origin and is triggered by a seed of deterministic nature, linked to the non-stationary of the process, rather than by thermal or zero-point fluctuations.