1308.0750 (M. Burrello et al.)

Topological phase transitions driven by non-Abelian gauge potentials in
optical square lattices    [PDF]

M. Burrello, I. C. Fulga, E. Alba, L. Lepori, A. Trombettoni

We analyze a tight-binding model of ultracold fermions loaded in an optical square lattice and subjected to a synthetic non-Abelian gauge potential featuring both a magnetic field and a translational invariant SU(2) term. We consider in particular the effect of broken time-reversal symmetry and its role in driving non-trivial topological phase transitions. By varying the spin-orbit coupling parameters, we find both a semimetal/insulator phase transition and a topological phase transition between insulating phases with a different number of edge states. The spin is not a conserved quantity of the system and the topological phase transitions can be detected by analyzing its polarization in time of flight images, providing a clear diagnostics for the characterization of the topological phases through the partial entanglement between spin and lattice degrees of freedom.

View original: http://arxiv.org/abs/1308.0750