title: Measuring the superfluid fraction of an ultracold atomic gas.
abstract: We propose a method to measure the superfluid fraction of an atomic gas. The method involves the use of a vector potential generated by optical beams with nonzero angular momenta to simulate uniform rotation. The induced change in angular momentum of the atomic gas can be measured spectroscopically. This allows a direct determination of the superfluid fraction.
authors.affiliation: Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Nigel R
authors.initials: NR
authors.lastname: Cooper
authors.forename: Zoran
authors.initials: Z
authors.lastname: Hadzibabic