Waterlike density anomaly in fermions

Abstract

In this work we explore the one-dimensional extended Hubbard model as a fluid system modelling liquid phases of different densities. This model naturally displays two length scales of interaction, which are connected with waterlike anomalies. We analyze the density anomaly as a function of the model parameters, namely the hopping, on-site and first neighbor interactions. We show that this anomaly is present for a wide range of model parameters and is connected to a ground-state liquid-liquid critical point.