The Mott insulator - 10th order perturbation theory extended to infinite order using QMC

TL;DR

This paper introduces a novel method combining analytical and numerical techniques within DMFT to extend 10th order perturbation theory to infinite order, providing highly precise estimates for the Mott insulator's properties.

Contribution

It extends strong-coupling perturbation theory to infinite order using QMC within DMFT, achieving unprecedented precision in energy and double occupancy calculations.

Findings

Precise estimates of energy and double occupancy for the Mott insulator.

Identification of the critical interaction strength U_{c1}=4.78.

Relevance to experimental studies on V_2O_3.

Abstract

We present a new method, based on the combination of analytical and numerical techniques within the framework of the dynamical mean-field theory (DMFT). Building upon numerically exact results obtained in an improved quantum Monte Carlo (QMC) scheme, 10th order strong-coupling perturbation theory for the Hubbard model on the Bethe lattice is extrapolated to infinite order. We obtain continuous estimates of energy E and double occupancy D with unprecedented precision O(10^{-5}) for the Mott insulator above its stability edge U_{c1}=4.78 as well as critical exponents. The relevance for recent experiments on Cr-doped V_2O_3 is pointed out.