Quantum Fields near Black Holes

This review gives an introduction into problems, concepts and techniques when quantizing matter fields near black holes. The first part focusses on quantum fields in general curved space-times. The second part is devoted to a detailed treatment of the Unruh effect in uniformly accelerated frames and the Hawking radiation of black holes. Paricular emphasis is put on the induced energy momentum tensor near black holesComment: 33 pages, Latex, 5 figure

Functional Schroedinger Equation for Fermions in External Gauge Fields

We discuss the functional Schroedinger picture for fermions in external fields for both stationary and time-dependent problems. We give formal results for the ground state and the solution of the time-dependent Schroedinger equation for QED in arbitrary dimensions, while more explicit results are obtained in two dimensions. For both the massless and massive Schwinger model we give an explicit expression for the ground state functional as well as for the expectation values of energy, electric and axial charge. We also give the corresponding results for non-abelian fields. We solve the functional Schroedinger equation for a constant external field in four dimensions and obtain the amount of particle creation. We solve the Schroedinger equation for arbitrary external fields for massless QED in two dimensions and make a careful discussionof the anomalous particle creation rate. Finally, we discuss some subtleties connected with the interpretation of the quantized Gauss constraint.Comment: 44 pages, LaTex File, preprint Freiburg THEP-94/2 and ETH-TH/93-17, hep-th/9306161, corrected version (in particular the particle production

The Phase Diagram for Wess-Zumino Models

Dynamical supersymmetry breaking is an important issue for applications of supersymmetry in particle physics. The functional renormalization group equations allow for a nonperturbative approach that leaves supersymmetry intact. Therefore they offer a promising tool to investigate dynamical supersymmetry breaking. Here we will employ this method to derive the phase diagram and a surprisingly rich RG fixed-point structure with corresponding critical exponents for the $\mathcal N=1$ Wess-Zumino model in two dimensions.Comment: 4 pages, 4 figures, talk given at SUSY09, Boston, MA, 5-10 June 2009, to appear in the proceeding

Two-dimensional N=2\mathcal{N}=2 Super-Yang-Mills Theory

Supersymmetry is one of the possible scenarios for physics beyond the standard model. The building blocks of this scenario are supersymmetric gauge theories. In our work we study the $\mathcal{N}=1$ Super-Yang-Mills (SYM) theory with gauge group SU(2) dimensionally reduced to two-dimensional $\mathcal{N}=2$ SYM theory. In our lattice formulation we break supersymmetry and chiral symmetry explicitly while preserving R symmetry. By fine tuning the bar-mass of the fermions in the Lagrangian we construct a supersymmetric continuum theory. To this aim we carefully investigate mass spectra and Ward identities, which both show a clear signal of supersymmetry restoration in the continuum limit.Comment: 8 pages, 3 figures, 2 tables, talk presented at the 35th International Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spai