Modern Physics Letters B

DERIVATION OF THE EXACT ENERGY FUNCTIONAL OF THE GROUND STATE OF LARGE POLARONS

Vladimir Onoochin

Published Jul 10, 1993• 0 citations

Abstract

The functional of the ground-state energy of large polarons is considered. After a canonical transformation and elimination of the field oscillators variables, the functional is presented in form convenient for further analysis. One can conclude that the type of ground state of each field oscillator is the coherent state.

DOI: 10.1142/s0217984993001107

Related papers

Dynamical Theory of the Large Polaron: Fock Approximation

D. Matz, B.C. Burkey

A Green's-function equation-of-motion analysis of the large polaron is presented. Existing theories for the ground-state energy and effective mass are obtained from a nondiagonal form of the Fock approximation to the electron self-energy. A connection between the usual canonical transformation techniques and the Green's-function approach is given explicitly. The effects of vertex corrections and translational invariance are examined in the context of these results.

Physical review. B, Solid stateMay 15, 197144 citations

Large polaron in bilocal field theory

Marvin Rich

The formalism of bilocal field theory was applied to the calculation of the ground-state energy and the effective mass of the large polaron. This calculation illustrates the bilocal field method using a relatively realistic model of a physical system. In bilocal theory the fermion field is dependent on two spatial points (nonrelativistically). Fermi particles can then be described in terms of a center of mass and internal wave function, and field operators can be expanded in functions related to the exact one-fermion Green's function, thereby eliminating self-energy terms from the S matrix and related operators. Similarities and differences between calculated large-polaron properties using the bilocal treatment and the customary local treatment are discussed. In particular, it is found that, within the approximations made, the bilocal and local methods give the same leading term in powers of the coupling constant for the ground-state energy and effective mass in the strong-coupling limit. For weak coupling, the bilocal energy is larger (more positive) and the effective mass smaller than in the local case due to an additional kinetic energy of internal motion.

Physical Review AJun 1, 19901 citation

On the Ground State Energy of a Gas of Interacting Polarons

L. F. Lemmens, F. Brosens, J. T. Devreese

Abstract Using a canonical transformation the Hamiltonian of a gas of interacting polarons is studied. After elimination of the phonons the reduced Hamiltonian describes a system of charged particles interacting through an effective interparticle potential. The Hartree‐Fock ground state of the reduced system is analysed.

physica status solidi (b)Aug 1, 197757 citations

A Comparison of two Methods to Calculate the Ground-state Energy of a Polaron

Wen Liu, Su Xiyu, Meng Fan-hua

Based on LLP canonical transformation,a different polaron ground-state which includes the two-phonon correlation is adopted to calculate the ground-state energy of polaron.The energy created by two-phonon correlation is obtained.The result shows that the ground-state energy obtained including the correlation effect is smaller than that obtained by perturbative theory.

Journal of Qufu Normal UniversityJan 1, 20060 citations

FUNCTIONAL INTEGRAL APPROACH AND THE EIKONAL APPROXIMATION TO THE POLARON ENERGY AND MASS

Nhu Xuan Nguyen, Toan Thang Vu

This article uses the functional integral method and eikonal approximation to calculate the first-order correction for the energy and (effective) mass of the Polaron. The obtained results have demonstrated the effectiveness of the functional integral method compared to conventional perturbation theory when considering the Polaron problem in solid crystal.

Apr 30, 20240 citations

Two- and three-dimensional polarons with extended coherent states

Chen Qinghu, Fang Minghu, Zhang Qirui +2 more

The properties of two- and three-dimensional polarons are investigated with the use of extended coherent states. In the weak-coupling limit, the obtained expansions for the ground-state energy and effective mass to the second order in the coupling constant \ensuremath{\alpha} are the same as the previous exact ones. Moreover, in the intermediate-coupling regime, the numerical results for the ground-state energy and effective mass agree with the results by the Feynman path-integral method, and perhaps closer to the exact results than the Feynman ones. It is suggested that the present approach should be an effective one in polaron physics. \textcopyright{} 1996 The American Physical Society.

Physical review. B, Condensed matterMay 1, 199617 citations