title: Critical Velocity and Dissipation of an Ultracold Bose-Fermi Counterflow.
abstract: We study the dynamics of counterflowing bosonic and fermionic lithium atoms. First, by tuning the interaction strength we measure the critical velocity v(c) of the system in the BEC-BCS crossover in the low temperature regime and we compare it to the recent prediction of Castin et al., C. R. Phys. 16, 241 (2015). Second, raising the temperature of the mixture slightly above the superfluid transitions reveals an unexpected phase locking of the oscillations of the clouds induced by dissipation.
authors.affiliation: Laboratoire Kastler Brossel, ENS-PSL, CNRS, UPMC-Sorbonne Universités, and Collège de France, 75005 Paris, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Delehaye
authors.affiliation: Laboratoire Kastler Brossel, ENS-PSL, CNRS, UPMC-Sorbonne Universités, and Collège de France, 75005 Paris, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Laurent
authors.affiliation: Laboratoire Kastler Brossel, ENS-PSL, CNRS, UPMC-Sorbonne Universités, and Collège de France, 75005 Paris, France.
authors.forename: Igor
authors.initials: I
authors.lastname: Ferrier-Barbut
authors.affiliation: Laboratoire Kastler Brossel, ENS-PSL, CNRS, UPMC-Sorbonne Universités, and Collège de France, 75005 Paris, France.
authors.forename: Shuwei
authors.initials: S
authors.lastname: Jin
authors.affiliation: Laboratoire Kastler Brossel, ENS-PSL, CNRS, UPMC-Sorbonne Universités, and Collège de France, 75005 Paris, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Chevy
authors.affiliation: Laboratoire Kastler Brossel, ENS-PSL, CNRS, UPMC-Sorbonne Universités, and Collège de France, 75005 Paris, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Salomon