An estimate of the Kac transfer operator
The authors compare the exponential group of a Schrödinger operator with the corresponding Kac transfer operator. The result of \textit{B. Helffer} [Oper. Theory, Adv. Appl. 78, 161-174 (1995; Zbl 0835.47050)] is derived here in a more general setting and by different methods that rely on holomorphic semigroups and estimates of commutators.
scientific article; zbMATH DE number 1006671