"Bose-Fermi dual superfluids" Christophe Salomon

We are pleased to announce the seminar by Dr. Christophe Salomon, Research Director, ENS, LKB, CNRS, France.

This lecture is a part of the summer school CQD2017

Everyone is welcome!

Speaker: Christophe Salomon
Date: Wednesday, 27 September
Time: 14:45-16:00
Venue: B250, Level B, Center Building

Title: Bose-Fermi dual superfluids

Abstract:
We will report on the production and study of a mixture of Bose and Fermi superfluids. Such a
mixture has long been sought in liquid helium where superfluidity was achieved separately in
bosonic 4He and fermionic 3He. However due to strong interactions between isotopes, phase
separation occurs when the 3He concentration exceeds 6%, which, so far, has prevented reaching
simultaneous superfluidity for both species. Using dilute quantum gases where interactions
can be tuned, we have produced a Bose-Fermi mixture where both species are superfluid
[1]. By exciting center of mass oscillations of the mixture we probe the collective dynamics
of the system. Coherent energy exchange between the Bose and Fermi gas is observed with
very small damping below a certain critical velocity. We compare this critical velocity for
superfluid counterflow to a recent theoretical prediction [2,3]. Finally raising the temperature
of the system slightly above the superfluid transition reveals an unexpected phase-locking of
the oscillations induced by dissipation.