Chiral superfluid in a one-dimensional bipartite optical lattice

Abstract

We study the formation of a chiral mode in a one-dimensional bipartite optical potential with a double-well dispersion. The geometry of the first excited state is tuned such that two degenerate energy minima are formed at the quasimomentum $q=\ifmmode\pm\else\textpm\fi{}\ensuremath{\hbar}{k}_{0}/2$ of the first Brillouin zone. Based on the coupled-mode theory, an unconventional superfluid order ${p}_{q}\ifmmode\pm\else\textpm\fi{}i{p}_{\ensuremath{-}q}$ is formed between the interacting condensate components within the double-well dispersion band under well-defined phase-locked steady states.