Dynamics and thermodynamics of the pseudospin-electron model in the case of absence of the electron Hubbard correlation. I. The analytical consideration

TL;DR

This paper analyzes the dynamics and thermodynamics of a pseudospin-electron model without electron Hubbard correlation, using diagrammatic and mean field methods to compute correlation functions, mean values, and thermodynamic potential.

Contribution

It provides an analytical investigation of the pseudospin-electron model neglecting Hubbard correlation, employing diagrammatic and Hubbard-I approximations.

Findings

Calculated correlation functions and mean values.

Derived thermodynamical potential.

Analyzed the model's behavior without Hubbard correlation.

Abstract

Dynamics and thermodynamics of the model with local anharmonism in the case of absence of the electron (Hubbard) correlation is investigated in the present work. The correlation functions, mean values of pseudospin and particle number as well as the thermodynamical potential are calculated. The calculation is performed by diagrammatic method in the mean field approximation. Single--particle Green functions are taken in the Hubbard--I approximation.