Density matrix embedding theory for interacting electron-phonon systems

TL;DR

This paper extends density matrix embedding theory to include coupled fermion-boson systems, enabling accurate treatment of electron-phonon interactions in models like the Hubbard-Holstein, with results benchmarked against DMRG.

Contribution

It introduces a frequency-independent entanglement embedding formalism for fermion-boson systems within the DMET framework, applied to the Hubbard-Holstein model.

Findings

Successfully extended DMET to fermion-boson systems

Achieved results consistent with DMRG benchmarks

Demonstrated effectiveness on the Hubbard-Holstein model

Abstract

We describe the extension of the density matrix embedding theory (DMET) framework to coupled interacting fermion-boson systems. This provides a frequency-independent, entanglement embedding formalism to treat bulk fermion-boson problems. We illustrate the concepts within the context of the one-dimensional Hubbard-Holstein model, where the phonon bath states are obtained from the Schmidt decomposition of a self-consistently adjusted coherent state. We benchmark our results against accurate density matrix renormalization group calculations.