Orbital coupled dipolar fermions in an asymmetric optical ladder

Abstract

We study a quantum ladder of interacting fermions with coupled s and p orbitals. Such a model describes dipolar molecules or atoms loaded into a double-well optical lattice, dipole moments being aligned by an external field. The two orbital components have distinct hoppings. The tunneling between them is equivalent to a partial Rashba spin-orbital coupling when the orbital space (s, p) is identified as spanned by pseudo-spin 1/2 states. A rich phase diagram, including incommensurate orbital density wave, pair density wave and other exotic superconducting phases, is proposed with bosonization analysis. In particular, superconductivity is found in the repulsive regime.

Topological phases and edge modes of an uneven ladder

“…[10,11] Since the discovery of topological matters, intensive efforts have been devoted to more complicated architectures, among which topological ladders, consisting of several coupled chains, become a focus. Due to the quasione-dimensional (1D) nature and compatibility with various experimental tools, versatile topological properties have been explored in ladder architectures by further including interactions, [12][13][14] orbital degree, [15][16][17] spin degree, [18][19][20][21] disorder, [22,23] or implementing spin-orbit coupling and synthetic gauge field, [24,25] or engineering flat bands. [26][27][28] Recently, nonequilibrium dynamics [29][30][31][32] and quantum Hall signatures [33][34][35][36][37][38][39] induced by topology have also been investigated in ladder systems both theoretically and experimentally.…”