Detecting Entrainment in Fermi-Bose mixtures.

The defining property of superfluids is that they flow without resistance. Entrainment -- where one superfluid drags along another as it flows -- may thus seem counter-intuitive, yet it is perfectly consistent with the Galilean covariance and absence of dissipation in superfluid mixtures, and may play a critical role in neutron stars where proton and neutron entrainment may underlie the puzzeling occurance of pulsar glitches. Although predicted by Andreev and Bashkin in 1975 for superfluid $^{3}$He and $^{4}$He mixtures, entrainment remains to be detected experimentally in cold atomic gases since it is a small effect, appearing at second order in the inter-particle interaction. In this talk I shall present an experimental proposal for detecting entrainment in $^{6}$Li-$^{174}$Yb Fermi-Bose mixture, taking advantage of the large mass ratio and carefully suppressing mean-field effects.