Quantum-embedding description of the Anderson lattice model with the ghost Gutzwiller Approximation

TL;DR

This paper introduces the ghost Gutzwiller approximation, a new method for the Anderson lattice model, which accurately captures complex physics and agrees with dynamical mean field theory, outperforming the standard Gutzwiller approximation.

Contribution

The paper develops and benchmarks the ghost Gutzwiller approximation, demonstrating its effectiveness over the standard approach in modeling strongly correlated systems.

Findings

Standard Gutzwiller approximation can be significantly inaccurate in some regimes.

Ghost Gutzwiller approximation aligns well with dynamical mean field theory results.

The new method is computationally efficient and applicable to ab-initio studies.

Abstract

We present benchmark calculations of the Anderson lattice model based on the recently-developed "ghost Gutzwiller approximation". Our analysis shows that, in some parameters regimes, the predictions of the standard Gutzwiller approximation can be incorrect by orders of magnitude for this model. We show that this is caused by the inability of this method to describe simultaneously the Mott physics and the hybridization between correlated and itinerant degrees of freedom (whose interplay often governs the metal-insulator transition in real materials). Finally, we show that the ghost Gutzwiller approximation solves this problem, providing us with results in remarkable agreement with dynamical mean field theory throughout the entire phase diagram, while being much less computationally demanding. We provide an analytical explanation of these findings and discuss their implications within the context of ab-initio computation of strongly-correlated matter.