Non-Hermitian Hubbard model without the sign problem

Abstract

We study the Hubbard model with non-Hermitian asymmetric hopping terms. The conjugate hopping terms are introduced for two spin components so that the negative sign is canceled out. This ensures that the quantum Monte Carlo simulation is free from the negative sign problem. We analyze the antiferromagnetic order and its suppression by the non-Hermiticity.

Comments: 5 pages, 4 figures; (v2) version accepted for publication in PRB