Dual Bose Fermi Superfluids: surprises in the ultracold world
le vendredi 14 décembre 2018 à 11h00
Colloque CPTGA
Personne à contacter :
Lieu : Amphithéâtre, maison des Magistères
Résumé : We will describe the first production and study of a novel quantum system, a mixture of Bose and Fermi superfluids. Such a mixture had long been sought in liquid helium where superfluidity was only achieved separately in bosonic 4He and fermionic 3He. Using dilute quantum gases where interactions can be tuned, we have produced a Bose-Fermi mixture where both species are in the superfluid state [1]. By exciting center of mass oscillations of the mixture we probe the equation of state of the strongly correlated Fermi gas [2]. The superfluid counterflow exhibits very small damping below a certain critical velocity [3]. This velocity is surprisingly high and is compared to a recent theoretical prediction [4]. Finally the lifetime of the Bose-Fermi mixture is governed by a very simple formula involving the fermionic two-body contact [5].
[1] Igor Ferrier-Barbut, Marion Delehaye, Sebastien Laurent, Andrew T. Grier, Matthieu Pierce, Benno S. Rem, Frédéric Chevy, Christophe Salomon, A Mixture of Bose and Fermi Superfluids, Science 345, 1035, (2014)
[2] N. Navon, S. Nascimbène, F. Chevy, C. Salomon, Science 328, 729-732 (2010)
[3] M. Delehaye, S. Laurent, I. Ferrier-Barbut, S. Jin, F. Chevy, and C. Salomon, Critical Velocity and Dissipation of an ultracold Bose-Fermi Counterflow, Phys. Rev. Lett., 115, 265303 (2015).
[4] Y. Castin, I. Ferrier-Barbut, and C. Salomon, The Landau critical velocity for a particle in a Fermi superfluid, Comptes Rendus Physique, 16, 241 (2015).
[5] S. Laurent, M. Pierce, M. Delehaye, T. Yefsah, F. Chevy, C. Salomon, Connecting few-body inelastic decay to quantum correlations in a many-body system : a weakly coupled impurity in a resonant Fermi gas, Phys. Rev. Lett., 118, 103403 (2017).
Laboratoire de Physique et Modélisation des Milieux Condensés
