Renormalization Flow, Duality, and Supersymmetry Breaking in Some N=1 Product-Group Theories

We discuss the renormalization group flow, duality, and supersymmetry breaking in N = 1 supersymmetric SU(N)xSU(M) gauge theories.Comment: Talk given at SUSY'96; 3 pages, LateX, style-, ps-files include

"Light from chaos" in two dimensions

We perform a Monte-Carlo study of the lattice two-dimensional gauged XY-model. Our results confirm the strong-coupling expansion arguments that for sufficiently small values of the spin-spin coupling the ``gauge symmetry breaking" terms decouple and the long-distance physics is that of the unbroken pure gauge theory. We find no evidence for the existence, conjectured earlier, of massless states near a critical value of the spin-spin coupling. We comment on recent remarks in the literature on the use of gauged XY-models in proposed constructions of chiral lattice gauge theories.Comment: 6 pages, 7 figure

Dynamical Supersymmetry Breaking versus Run-away behavior in Supersymmetric Gauge Theories

We consider Dynamical Supersymmetry Breaking (DSB) in models with classical flat directions. We analyze a number of examples, and develop a systematic approach to determine if classical flat directions are stabilized in the full quantum theory, or lead to run-away behavior. In some cases pseudo-flat directions remain even at the quantum level before taking into account corrections to the K\"ahler potential. We show that in certain limits these corrections are calculable. In particular, we find that in the Intriligator-Thomas $SU(2)$ and its generalizations, a potential for moduli is generated. Moreover, there is a region of the parameter space where K\"ahler potential corrections lead to calculable (local) minima at large but finite distance from the origin.Comment: 13 pages, uses harvmac; discussion of run-away behavior in $SU(N-M) \times SU(N)$ model is clarifie

Chiral Lattice Gauge Theories and The Strong Coupling Dynamics of a Yukawa-Higgs Model with Ginsparg-Wilson Fermions

The Yukawa-Higgs/Ginsparg-Wilson-fermion construction of chiral lattice gauge theories described in hep-lat/0605003 uses exact lattice chirality to decouple the massless chiral fermions from a mirror sector, whose strong dynamics is conjectured to give cutoff-scale mass to the mirror fermions without breaking the chiral gauge symmetry. In this paper, we study the mirror sector dynamics of a two-dimensional chiral gauge theory in the limitof strong Yukawa and vanishing gauge couplings, in which case it reduces to an XY model coupled to Ginsparg-Wilson fermions. For the mirror fermions to acquire cutoff-scale mass it is believed to be important that the XY model remain in its "high temperature" phase, where there is no algebraic ordering--a conjecture supported by the results of our work. We use analytic and Monte-Carlo methods with dynamical fermions to study the scalar and fermion susceptibilities, and the mirror fermion spectrum. Our results provide convincing evidence that the strong dynamics does not "break" the chiral symmetry (more precisely, that the mirror fermions do not induce algebraic ordering in two-dimensions), and that the mirror fermions decouple from the infrared physics.Comment: 44 pages, 18 figures; v2: clarification of fermion operators, discussion of recent related work

Dynamical Supersymmetry Breaking

I review the motivation for dynamical supersymmetry breaking, the various mechanisms which have been discovered, and the prospects for model building.Comment: 5 pages. invited talk given at SUSY97, May27-31, 1997, University of Pennsylvani

Warp Factors and Extended Sources in Two Transverse Dimensions

We study the solutions of the Einstein equations in (d+2)-dimensions, describing parallel p-branes (p=d-1) in a space with two transverse dimensions of positive gaussian curvature. These solutions generalize the solutions of Deser and Jackiw of point particle sources in (2+1)-dimensional gravity with cosmological constant. Determination of the metric is reduced to finding the roots of a simple algebraic equation. These roots also determine the nontrivial "warp factors" of the metric at the positions of the branes. We discuss the possible role of these solutions and the importance of "warp factors" in the context of the large extra dimensions scenario.Comment: 11 pages, LaTeX; References and acknowledgments adde