Importance of subleading corrections for the Mott critical point

TL;DR

This paper investigates how subleading corrections influence the critical behavior of the Mott transition, revealing that they can cause deviations from mean-field exponents, with implications for experimental observations.

Contribution

The study demonstrates the significance of subleading corrections in the Mott critical point, using advanced cluster dynamical mean-field theory to clarify universality class deviations.

Findings

Subleading corrections can alter critical exponents from mean-field predictions.

Accurate double occupancy calculations are achieved via a sign-problem-minimized transformation.

Experimental optical lattice studies could verify the predicted effects.

Abstract

The interaction-induced metal-insulator transition should be in the Ising universality class. Experiments on layered organic superconductors suggest that the observed critical endpoint of the first-order Mott transition belongs instead to a different universality class. To address this question, we use dynamical mean-field theory and a cluster generalization that is necessary to account for short-range spatial correlations in two dimensions. Such calculations can give information on crossover effects, in particular quantum ones, that are not included in the simplest mean-field. In the cluster calculation, a canonical transformation that minimizes the sign problem in continuous-time quantum Monte Carlo calculations allows us to obtain very accurate results for double occupancy. These results show that there are important subleading corrections that can lead to apparent exponents that are different from mean-field. Experiments on optical lattices could verify our predictions.