Thermodynamics of the Quantum Critical Point at Finite Doping in the 2D Hubbard Model: A Dynamical Cluster Approximation Study

TL;DR

This study investigates the thermodynamics near the quantum critical point in the 2D Hubbard model using dynamical cluster approximation and quantum Monte Carlo, revealing signatures of quantum criticality in entropy, double occupancy, and specific heat behaviors.

Contribution

It introduces a detailed thermodynamic analysis of the 2D Hubbard model at finite doping, highlighting quantum critical behavior using advanced computational methods.

Findings

Peak in entropy/S at critical doping

Strong increase in C/T as temperature decreases

Kinetic and potential energies vary as T^2 ln(T)

Abstract

We study the thermodynamics of the two-dimensional Hubbard model within the dynamical cluster approximation. We use continuous time quantum Monte Carlo as a cluster solver to avoid the systematic error which complicates the calculation of the entropy and potential energy (double occupancy). We find that at a critical filling, there is a pronounced peak in the entropy divided by temperature, S/T, and in the normalized double occupancy as a function of doping. At this filling, we find that specific heat divided by temperature, C/T, increases strongly with decreasing temperature and kinetic and potential energies vary like T^2 ln(T). These are all characteristics of quantum critical behavior.