arXiv subjects
Publications and source records attributed to Volkhard F. Müller.
For a linear Dirac field on a globally hyperbolic static space-time the analytic continuation of its Wightman functions (Green functions) to Schwinger functions and back at zero and finite temperature is shown.
In this article a self-contained exposition of proving perturbative renormalizability of a quantum field theory based on an adaption of Wilson's differential renormalization group equation to perturbation theory is given. The topics treated include the spontaneously broken SU(2) Yang-Mills theory. Although mainly a coherent but selective review, the article contains also some simplifications and extensions with respect to the literature. In the original version of this review the spontaneously broken Yang-Mills theory, dealt with in Chapter 4, followed Comm. Math. Phys. 209, 477 (2000) . Recently, however, the authors of this article discovered a serious deficiency in their method to restore the Slavnov-Taylor identities (intermediately violated by the regularization), which invalidates their claim. Now in Rev. Math. Phys. 21, 781 (2009) these authors have developed a new approach to accomplish the missing restoration of the Slavnov-Taylor identities. The present revised review concerns solely Chapter 4: the original Sections 4.1-4.3 are essentially unaltered, whereas the former Section 4.4, now obsolete, has been replaced by the new Sections 4.4-4.6, following the recent Rev. Math. Phys. article.
We present a renormalizability proof for spontaneously broken SU(2) gauge theory based on Flow Equations. It is a conceptually and technically simplified version of the earlier paper [KM] including some extensions. The proof of [KM] also was incomplete since an important assumption made implicitly in the proof of Lemma 2 there is not verified. So the present paper is also a corrected version of [KM].
In this paper we present an inductive renormalizability proof for massive $\vp_4^4$ theory on Riemannian manifolds, based on the Wegner-Wilson flow equations of the Wilson renormalization group, adapted to perturbation theory. The proof goes in hand with bounds on the perturbative Schwinger functions which imply tree decay between their position arguments. An essential prerequisite are precise bounds on the short and long distance behaviour of the heat kernel on the manifold. With the aid of a regularity assumption (often taken for granted) we also show, that for suitable renormalization conditions the bare action takes the minimal form, that is to say, there appear the same counter terms as in flat space, apart from a logarithmically divergent one which is proportional to the scalar curvature.
We analyse 4-dimensional massive $\vp^4$ theory at finite temperature T in the imaginary-time formalism. We present a rigorous proof that this quantum field theory is renormalizable, to all orders of the loop expansion. Our main point is to show that the counterterms can be chosen temperature independent, so that the temperature flow of the relevant parameters as a function of $T$ can be followed. Our result confirms the experience from explicit calculations to the leading orders. The proof is based on flow equations, i.e. on the (perturbative) Wilson renormalization group. In fact we will show that the difference between the theories at T>0 and at T=0 contains no relevant terms. Contrary to BPHZ type formalisms our approach permits to lay hand on renormalization conditions and counterterms at the same time, since both appear as boundary terms of the renormalization group flow. This is crucial for the proof.