Walter Dittrich

Effective QCD-lagrangian with ξ-function regularization

Abstract We show how to construct the effective lagrangian in QCD employing Hawkings ξ-function method. The various loops are attached to all orders to the external covariant constant colormagnetic background field. Our construction of the effective potential is far less difficult than the various computations found so far in the literature, e.g., via proper-time or dimensional regularization methods.

Finite temperature effects in QED

Abstract The one-loop effective potential at finite temperature is derived for scalar and spinor QED in presence of an external constant magnetic field. In particular, the high-temperature limit is investigated.

On the quantum corrections in synchrotron radiation

Abstract The recent controversy over the importance of the quantum corrections in synchrotron radiation up to second order in h ω/E is discussed by presenting still another calculation which indicates that there are no second-order quantum mechanical corrections which are more important than the first-order correction or even dominate the classical expression. Our analysis is based on Schwingers proper-time method; nevertheless, an independent approximation scheme had to be developed in order to discriminate between the two rival opinions on the matter.