Abstract:
The method of two-time Green's functions is used to obtain an expression for the free energy
as a cumulant expansion in irreducible correlation functions; this is represented as an
expansion in the renormalized anharmonic interaction. A selfeonsistent approach to the calculation
of the free energy is considered and a closed expression is obtained for it in the second
order in the interaction.
Fulltext:
PDF file (1236 kB)
