3 papers
hep-th2025
Functorial properties of Schwinger-DeWitt expansion and Mellin-Barnes representation
Andrei O. Barvinsky, Alexey E. Kalugin, WÅadysÅaw Wachowski
We consider integral kernels for functions of a minimal second-order differential operator on a curved spacetime. We show that they can be expanded in…
hep-th2025
Pseudodifferential calculus in Schwinger--DeWitt formalism: UV and IR parts
A. O. Barvinsky, A. E. Kalugin, W. Wachowski
We consider expansions for the kernels of operator functions of second-order minimal operators on a curved background. We show that the terms of these expansions originate in the u…
hep-th2025
Schwinger--DeWitt expansion for the heat kernel of nonminimal operators in causal theories
Andrei O. Barvinsky, Alexey E. Kalugin, WÅadysÅaw Wachowski
We suggest a systematic calculational scheme for heat kernels of covariant nonminimal operators in causal theories whose characteristic surfaces are null with respect to a generic…