Analogue Schwinger Pair Production in Acoustic Black Holes

Abstract

We show that an analogue Schwinger pair production can be realized in Reissner-Nordstr{ö}m-like acoustic black holes constructed from a Bose-Einstein condensate subject to a synthetic vector potential. Upon Kaluza-Klein reduction of the five-dimensional acoustic geometry, the higher-dimensional phonon modes appear as effectively charged phonons in the resulting four-dimensional spacetime, in which the electric field experienced by the charged phonons arises from the component of the synthetic vector potential along the compactified direction. Then by appropriately choosing the background flow velocity and the synthetic vector potential, the reduced acoustic metric can take the form of a Reissner-Nordstr{ö}m-like black hole. From this metric we obtain the mean number of spontaneously produced phonon pairs in both the extremal and near extremal cases, and show that in the extremal limit this mean number takes the form of the Schwinger formula. Moreover, charged-phonon pair production not only admits the same effective thermal interpretation as Schwinger pair production of real charged particles, but can also be interpreted as the analogue Hawking radiation and superradiance from the five-dimensional perspective. Finally, we make estimates of pair production using experimental parameters in Bose-Einstein condensate, providing theoretical guidance for future laboratory detection.