Entanglement spectrum and entropy in non-Hermitian systems*

In this talk, we study both the entanglement spectrum and the entanglement entropy by use of a biothogonal basis in non-Hermitian free fermion systems. We show the entanglement spectrum can characterize topological features in the non-Hermitian Su-Schrieffer-Heeger model with parity and time reversal symmetry. In addition, we find the entanglement entropy at the critical point of this model has a logarithmic scaling with corresponding central charge c=-2, which can be described by the non-unitary conformal field theory.