Topological phase transitions for interacting finite systems

Christopher N. Varney, Kai Sun, Marcos Rigol, Victor Galitski
2011 Physical Review B  
In this paper, we investigate signatures of topological phase transitions in interacting systems. We show that the key signature is the existence of a topologically protected level crossing, which is robust and sharply defines the topological transition, even in finite-size systems. Spatial symmetries are argued to play a fundamental role in the selection of the boundary conditions to be used to locate topological transitions in finite systems. We discuss the theoretical implications of this
more » ... ult, and utilize exact diagonalization to demonstrate its manifestations in the Haldane-Fermi-Hubbard model. Our findings provide an efficient way to detect topological transitions in experiments and in numerical calculations that cannot access the ground-state wave function.
doi:10.1103/physrevb.84.241105 fatcat:e4xghanydvddhb7ooxf365g2ba