Orbital hybridized topological Fulde-Ferrel superfluidity in a noncentrosymmetric optical lattice

Abstract: Topological phases like topological insulators or superconductors are fascinating quantum states of matter, featuring novel properties such as emergent chiral edge states or Majorana fermions with non-Abelian braiding statistics. The recent experimental implementation of optical lattices with highly tunable geometry in cold gases opens up a new thrust on exploring these novel quantum states. Here we report that the topological non-trivial Bloch bands can arise naturally in a noncentrosymmetric lattice. It induces a controllable orbital hybridization, producing the topological band structure. In such bands, when considering attractive fermionic atoms, we find a topological Fulde-Ferrell superfluid state with finite center-of-mass momentum in the presence of onsite rotation. This topological superfluid supports Majorana fermions on its edges. Experimental signatures are predicted for cold gases in radio-frequency spectroscopy.