Title: ANALYTIC PECULIARITIES OF THE POLARON MASS OPERATOR IN THE FIRST TWO ORDERS OF THE COUPLING CONSTANT
Authors: M.Tkach, O.Voitsekhivska, O.Val' (Chernivtsi State University, Department of Theoretical Physics, 2 Kotsubynsky St., UA-274012 Chernivtsi, Ukraine)

The exact analytic expression for the polaron mass operator in the second order of the coupling constant is established for the first time. It holds in the whole energy scale. The peculiarities of the mass operator are analysed. The renormalized polaron energy spectrum is obtained and analysed in this approximation.

Key words: polaron, mass operator, diagram technique
Comments: Figs. 2, Refs. 5, Tabs. 0.