Critical entanglement for the half-fIlled extended Hubbard model

Abstract

We study the ground state of the one-dimensional extended Hubbard model at half filling using the entanglement entropy calculated by density matrix renormalization-group techniques. We apply curve fitting and scaling methods to accurately identify a second-order critical point as well as a Berezinskii-Kosterlitz-Thouless critical point. Using open boundary conditions and medium-sized lattices with very small truncation errors, we are able to achieve similar accuracy to that of previous authors. We also report observations of finite-size and boundary effects that can be remedied with careful pinning.