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A Two‐Particle Model for the Ground State Energy of the Polaron
Author(s) -
Bader G.,
Lépine Y.
Publication year - 1981
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221030118
Subject(s) - feynman diagram , polaron , path integral formulation , vertex (graph theory) , physics , ground state , unitary state , kinetic energy , quantum electrodynamics , electron , quantum mechanics , mathematical physics , mathematics , graph , combinatorics , quantum , political science , law
The dielectric polaron is treated using the Gross unitary transform and the Matz‐Green's function techniques. A two‐particle Feynman‐like model is introduced to compare these methods with the best Feynman path integral formulation. It is found that the introduction of a second particle in the model problem does not improve on the usual result for a one‐particle model. However, a comparison of these different approaches leads to the conclusion that no vertex contributions are contained in the Feynman approximation. It is also concluded that it is the very special treatment of the kinetic energy of the electron in Feynman's theory that makes his results lower in energy.