Condensed Matter Physics, 1997, No 9, p. 107-116, English
DOI:10.5488/CMP.9.107
Title: BRANCHING INTEGRAL FRACTION IN THE THEORY OF THE SPECTRUM
OF QUASIPARTICLES INTERACTING WITH PHONONS
Authors: M.V.Tkach (Chernivtsi State University, Department of
Theoretical Physics, 2 M.Kotsyubynskii St., UA-274012 Chernivtsi,
Ukraine)
For the system of the quasiparticles interacting with arbitrary number of
phonon modes at T=0 K on the basis of the Feinman diagram technique the
exact representation of the Green function in the form of the infinite
branching integral fraction was obtained. It is shown that thus the
developed method of the calculation of the Green functions monotypically
takes into account virtual many-phonon processes, it gives an opportunity to
obtain the spectrum of the system at the arbitrary binding values and in any
region of energies and quasiimpulses quickly and effectively. It is
established that in the system of dispersionless quasiparticles interacting
with many-mode phonons the excited states are convergent infinite series of
energy levels.
Comments: Figs. 4, Refs. 13, Tabs. 0.