project title: Hydraulic jump in superfluids
project leader: Etienne Rolley
access given (in days): 14
access used (in days): 7
local host: Grigory Volovik
home institution: Department of Physics, ENS, Paris
country of institution: France
starting date (yyyy-mm-dd): 2006-03-26
In recent experiments with superfluid helium-4 made in ENS (Paris), the hydraulic jump has been observed and investigated. Inside the hydraulic jump the standing surface waves have been observed, which demonstrated the instability of the surface of the liquid towards the formation of surface waves -- ripplons. A very similar instability towards the formation of the ripplons has been observed at the interface between superfluid 3He-A and superfluid 3He-B in the experiments made at the rotating cryostat in the Low Temperature Laboratory of HUT. The goal of the project is to study this common phenomenon, which also has analog with the instability of the quantum vacuum inside the black hole or white hole horizons and ergo-regions. This will finally allow us to model in the laboratory the processes related to the behavior of the quantum fields in the curved space of general relativity.
Further investigations demonstrated that under the conditions of the experiment the hydraulic jump in superfluid 4He is very similar to that in the normal liquid 4He. The position of the hydraulic jump as a function of temperature does not experience discontinuity at the superfluid transition. Moreover, the standing surface waves inside the horizon have been also observed in normal liquid 4He and even in water. This demonstrated that the dynamics of instability of the white-hole and black-hole horizons can be simulated in a large class of condensed matter systems.