1203.5541 (Achim Rosch)

Unwinding of a one-dimensional topological insulators    [PDF]

Achim Rosch

We show that a topological insulator made of four chains of superconducting spinless fermions characterized by four Majorana edge states can adiabatically be deformed into a trivial band insulator. To unwind this time-reversal invariant topological insulator, interactions to {\em spinful} fermions are switched on along an adiabatic path. Thereby, we couple modes which belong to two different representations of the time-reversal symmetry operator T with T^2=1 and T^2=-1, respectively. This observation can easily be understood by investigating how the relevant symmetries act on the entanglement spectrum giving rise to a Z_4 instead of a Z_8 classification of the interacting system. We also show that a simple level crossing of doubly and singly degenerate states occurs in the entanglement spectrum upon deforming the quantum state.

View original: http://arxiv.org/abs/1203.5541