Girma Hailu

Brane couplings from bulk loops

Abstract We compute loop corrections to the effective action of a field theory on a five-dimensional S 1 / Z 2 orbifold. We find that the quantum loop effects of interactions in the bulk produce infinite contributions that require renormalization by four-dimensional couplings on the orbifold fixed planes. Thus bulk couplings give rise to renormalization group running of brane couplings.

Chiral fermions, orbifolds, scalars and fat branes

We note that orbifold boundary conditions that produce chiral fermion zero modes in compactified higher dimensional theories may distort scalar field vacuum expectation values, giving rise to nontrivial dependence on the extra dimensions. We illustrate this in a simple five dimensional model which has chiral fermion zero-modes stuck to fat branes. The model could provide a simple and explicit realization of the separation of quarks and leptons in the fifth dimension. We discuss the KK expansion in some detail. We find that there are in general non-zero-mode states stuck to the brane, like the chiral zero modes. We see explicitly the transition from states dominated by the internal structure of the fat brane to those dominated by the compactification.

N = 1 supersymmetric SU ( 2 ) r moose theories

We study the quantum moduli spaces and dynamical superpotentials of four-dimensional

On exact superpotentials, free energies and matrix models

{\mathrm{SU}(2)}^{r}

Quantum moduli spaces of linear and ring mooses

linear and ring moose theories with

Glueball masses from linearly confining supergravity

\mathcal{N}=1

Linear Confinement of Quarks from Supergravity

supersymmetry and link chiral superfields in the fundamental representation. Nontrivial quantum moduli spaces and dynamical superpotentials are produced. When the moduli space is perturbed by a generic tree level superpotential, the vacuum space becomes discrete. The ring moose is in the Coulomb phase and we find two singular submanifolds with a nontrivial modulus that is a function of all the independent gauge invariants needed to parametrize the quantum moduli space. The massive theory near these singularities confines. The Seiberg-Witten elliptic curve that describes the quantum moduli space of the ring moose is produced.

Gravity Dual to Pure N=1 SU(N) Gauge Theory

We discuss exact results for the full nonperturbative effective superpotentials of four dimensional = 1 supersymmetric U(N) gauge theories with additional chiral superfield in the adjoint representation and the free energies of the related zero dimensional bosonic matrix models with polynomial potentials in the planar limit using the Dijkgraaf-Vafa matrix model prescription and integrating in and out. The exact effective superpotentials are produced including the leading Veneziano-Yankielowicz term directly from the matrix models. We also discuss how to use integrating in and out as a tool to do random matrix integrals in the large-N limit.

Quantum geometries of A2

Abstract Quantum moduli spaces of four-dimensional SU (2) r linear and ring moose theories with N =1 supersymmetry and link chiral superfields in the fundamental representation are produced starting from simple pure gauge theories of disconnected nodes.

Cosmology on Compact and Stable Supergravity Background

Mass spectrum of