We overview the main features of mobile impurities moving in one-dimensional superfluid backgrounds by modeling it as a mobile Josephson junction, which leads naturally to the periodic dispersion of the impurity. The dissipation processes, such as radiative friction and quantum viscosity, are shown to result from the interaction of the collective phase difference with the background phonons. We develop a more realistic depleton model of an impurity-hole bound state that provides a number of exact results interpolating between the semiclassical weakly interacting picture and the strongly interacting Tonks-Girardeau regime. We also discuss the physics of a trapped impurity, relevant to current experiments with ultra cold atoms.
Bibliographical noteFunding Information:
AKwas supported by NSF grant DMR1306734.MSwas supported by the Danish National Research Foundation and The Danish Council for Independent Research-Natural Sciences.MS andDMGgratefully acknowledge the hospitality of the University of Minnesota.
© 2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.
- 1D quantum liquids
- Bloch oscillations
- mobile impurity
- ultracold atoms