Matti Krusius, Aalto University, Finland
Title: Dynamics of quantized vortices in helium superfluids in the zero temperature limit
Matti Krusius is a researcher in the Low Temperature Laboratory of Aalto University. Currently his work deals with superfluids. The interest centers on the dynamics of these quantum systems in the largely unexplored zero-temperature limit. Particularly the isotropic B-phase of the fermion p-wave 3He superfluids is at the forefront at temperatures below 0.5 mK which can be explored only in 3 or 4 laboratories. New dissipation sources are identified in both turbulent and laminar vortex flow and new processes have been described by which the equilibrium state is reached when fluid flow is disturbed. One of the central questions is the loss of coupling of the superfluid to the external experimentally controlled reference frame in the limit of vanishing density of quasiparticle excitations. The work is performed with a rotating refrigerator where the lowest temperature is reached using adiabatic demagnetization cooling of a nuclear paramagnet. Only 2 or 3 such installations have been constructed so far and the apparatus at Aalto is unique in reaching the zero-temperature limit in rotation for the 3He superfluids.