Eur. Phys. J. B (2017) 90: 239
https://doi.org/10.1140/epjb/e2017-80304-4

Regular Article

Entanglement spectra of superconductivity ground states on the honeycomb lattice

Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany

^a e-mail: sonja.predin@physik.uni-regensburg.de

Received: 29 May 2017
Received in final form: 20 September 2017
Published online: 11 December 2017

Abstract

We analytically evaluate the entanglement spectra of the superconductivity states in graphene, primarily focusing on the s-wave and chiral d_x²-y² + id_xy superconductivity states. We demonstrate that the topology of the entanglement Hamiltonian can differ from that of the subsystem Hamiltonian. In particular, the topological properties of the entanglement Hamiltonian of the chiral d_x²-y² + id_xy superconductivity state obtained by tracing out one spin direction clearly differ from those of the time-reversal invariant Hamiltonian of noninteracting fermions on the honeycomb lattice.