Analog wormholes and black hole laser effects in hydrodynamics

PublishedWe numerically study water wave packets on a spatially varying countercurrent in the presence of surface tension. Depending on the details of the velocity profile, we show that traversable and bidirectional analogue wormholes exist in fluid mechanics. The limitations on traversability of wormholes in general relativity are absent here because of the dispersion of water waves and the ability to form flow profiles that are not solutions of Einstein’s equations. We observe that negative energy can be trapped between analogue horizons forming a laserlike cavity. Six horizons are involved in the trapping cavity because of the existence of two dispersive scales, in contrast to previous treatments which considered two horizons and one dispersive scale.This research was supported by the University of Poitiers (ACI UP on Wave-Current Interactions 2013–2014), by the Interdisciplinary Mission of CNRS (PEPS PTI 2014 DEMRATNOS) and by the University of Tours in a joint grant with the University of Poitiers (ARC Poitiers-Tours 2014–2015). The French National Research Agency (ANR) funds the current work on the subject through Grant No. HARALAB (ANR-15-CE30-0017-04). We thank Scott Robertson, Renaud Parentani and Florent Michel for comments on the draft