Bogoliubov depletion of the fragmented condensate in the bosonic flux   ladder
  We theoretically analyze the ground state of weakly interacting bosons in the flux ladder -- the system that has been recently realized by means of ultacold atoms in the specially designed optical lattice [M. Atala, et al., Nat. Phys. 10, 588 (2014)]. It is argued that, for the system parameters corresponding to the so-called `vortex phase', the ground state is a fragmented condensate. We study the Bogoliubov depletion of this condensate and discuss the role of boundary conditions. 
Andrey R. Kolovsky
cond-mat.quant-gas quant-ph