Variational path-integral treatment of a translation invariant many-polaron system

TL;DR

This paper develops a variational path-integral approach to analyze a translation invariant N-polaron system across all coupling strengths, providing bounds on ground state energy and insights into multipolaron formation.

Contribution

It introduces a novel variational path-integral method for N-polaron systems that accounts for electron-electron interactions and Fermi statistics, offering new bounds and criteria for multipolaron states.

Findings

Derived an upper bound for the ground state energy.

Analyzed addition energies and conditions for multipolaron formation.

Accounted for electron-electron interactions and Fermi statistics.

Abstract

A translation invariant N-polaron system is investigated at arbitrary electron-phonon coupling strength, using a variational principle for path integrals for identical particles. An upper bound for the ground state energy is found as a function of the number of spin up and spin down polarons, taking the electron-electron interaction and the Fermi statistics into account. The resulting addition energies and the criteria for multipolaron formation are discussed.