Title: Topological orbital superfluid with chiral d-wave order in a rotating optical lattice,
Abstract: Topological superfluid is an exotic state of quantum matter that possesses a
nodeless superfluid gap in the bulk and Andreev edge modes at the boundary of a
finite system. Here, we study a multi-orbital superfluid driven by attractive
s-wave interaction in a rotating optical lattice. Interestingly, we find that
the rotation induces the inter- orbital hybridization and drives the system
into topological orbital superfluid in accordance with intrinsically chiral
d-wave pairing characteristics. Thanks to the conservation of spin, the
topological orbital superfluid supports four rather than two chiral Andreev
edge modes at the boundary of the lattice. Moreover, we find that the intrinsic
harmonic confining potential forms a circular spatial barrier which accumulates
atoms and supports a mass current under injection of small angular momentum as
external driving force. This feature provides an experimentally detectable
phenomenon to verify the topological orbital superfluid with chiral d-wave
order in a rotating optical lattice.