Journal of Physical Studies 7(3), 275–282 (2003) DOI: https://doi.org/10.30970/jps.07.275 THE SPECTRAL REPRESENTATION OF STATISTICAL OPERATOR AND GREEN'S FUNCTIONS AT THE FINITE TEMPERATURE M. V. Vavrukh, S. B. Slobodyan The Ivan Franko National University of Lviv, Department for Astrophysics, 8 Kyryla and Mefodia Str., Lviv, UA-79005, Ukraine

The spectral representation of the statistical operator for the electron liquid model was suggested previosly by one of autors. This approach is generalized for homogeneous Fermi or Bose systems with many-particle interactions, as well as for the electron-phonon model. The spectral representation of Green's functions reference systems (particle or phonon) was proposed. It allows to formalize the calculation of the sum over the frequency and simplify the procedure of calculation of the pertubation theory diagram.

PACS number(s): 05.30.Fk

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