Topological invariants for interacting topological insulators with inversion symmetry

Understand

For interacting Z_2 topological insulators with inversion symmetry, we propose a simple topological invariant expressed in terms of the parity eigenvalues of the interacting Green's function at time-reversal invariant momenta.

• We derive this result from our previous formula involving the integral over the frequency-momenta space.
• This formula greatly simplifies the explicit calculation of Z_2 topological invariants in inversion symmetric insulators with strong interactions.