Nonadiabatic creation of macroscopic superpositions with strongly   correlated 1D bosons on a ring trap
  We consider a strongly interacting quasi-one dimensional Bose gas on a tight ring trap subjected to a localized barrier potential. We explore the possibility to form a macroscopic superposition of a rotating and a nonrotating state under nonequilibrium conditions, achieved by a sudden quench of the barrier velocity. Using an exact solution for the dynamical evolution in the impenetrable-boson (Tonks-Girardeau) limit, we find an expression for the many-body wavefunction corresponding to a superposition state. The superposition is formed when the barrier velocity is tuned close to multiples of integer or half-integer number of Coriolis flux quanta. As a consequence of the strong interactions, we find that (i) the state of the system can be mapped onto a macroscopic superposition of two Fermi spheres, rather than two macroscopically occupied single-particle states as in a weakly interacting gas, and (ii) the barrier velocity should be larger than the sound velocity to better discriminate the two components of the superposition. 
C. Schenke, A. Minguzzi and F. W. J. Hekking
cond-mat.quant-gas