Chiral Fermions and AdS/CFT Duality for a Nonabelian Orbifold

We present what we believe is the minimal three-family $AdS/CFT$ model compactified on a nonabelian orbifold $S^{5}/(Q\times Z_{3})$. Nontrivial irreps of the discrete nonabelian group $Q\times Z_{3}$ are identified with the $4$ of $SU(4)$ $R$ symmetry to break all supersymmetries, and the scalar content of the model is sufficient to break the gauge symmetry to the standard model. According to the conformality hypothesis the progenitor $SU(4)^3 \times SU(2)^{12}$ theory becomes conformally invariant at an infra-red fixed point of the renormalization group.Comment: 11 pages latex and one JPG figur

Recovering Infinities in Graviton Scattering Amplitudes using Cutkosky rules

We use the Cutkosky rules as a tool for determining the infinities present in graviton scattering amplitudes. We are able to confirm theoretical derivations of counterterms in Einstein-Maxwell theory and to determine new results in the Dirac-Einstein counter-Lagrangian.Comment: 10 pages, 4 Postscript figures, uses epsf.st

Calculation of Graviton Scattering Amplitudes using String-Based Methods

Techniques based upon the string organisation of amplitudes may be used to simplify field theory calculations. We apply these techniques to perturbative gravity and calculate all one-loop amplitudes for four-graviton scattering with arbitrary internal particle content. Decomposing the amplitudes into contributions arising from supersymmetric multiplets greatly simplifies these calculations. We also discuss how unitarity may be used to constrain the amplitudes.Comment: 25 pages +5 figs. , SWAT-94-37 UCLA/TEP/94/30, Plain TeX. (Typos in eqns. fixed

Non-commutative Duality: High Spin Fields and CP1CP^1 Model with Hopf Term

We show that the non-commutative $CP^1$ model coupled with Hopf term in 3 dimensions is equivalent to an interacting spin-$s$ theory where the spin $s$ of the dual theory is related to the coefficient of the Hopf term. We use the Seiberg-Witten map in studying this non-commutative duality equivalence, keeping terms to order $\theta$ and show that the spin of the dual theory do not get any $\theta$ dependant corrections. The map between current correlators show that topological index of the solitons in the non-commutative $CP^1$ model is unaffected by $\theta$ where as the Noether charge of the corresponding dual particle do get a $\theta$ dependence. We also show that this dual theory smoothly goes to the limit $\theta\to 0$ giving dual theory in the commutative plane.Comment: 13 pages, more references and a footnote are added. Version to appear in Phys. Lett.

ADS/CFT String Duality and Conformal Gauge Field Theories

Compactification of Type IIB superstring on an $AdS_5 \times S^5/\Gamma$ background leads to SU(N) gauge field theories with prescribed matter representations. In the 't Hooft limit of large N such theories are conformally finite. For finite N and broken supersymmetry ($\cal N$ = 0) I derive the constraints to be two-loop conformal and examine the consequences for a wide choice of $\Gamma$ and its embedding $\Gamma \subset {\cal C}^3 (\supset S^5)$.Comment: 10 pages LaTe

Staggered fermions and chiral symmetry breaking in transverse lattice regulated QED

Staggered fermions are constructed for the transverse lattice regularization scheme. The weak perturbation theory of transverse lattice non-compact QED is developed in light-cone gauge, and we argue that for fixed lattice spacing this theory is ultraviolet finite, order by order in perturbation theory. However, by calculating the anomalous scaling dimension of the link fields, we find that the interaction Hamiltonian becomes non-renormalizable for $g^2(a) > 4\pi$, where $g(a)$ is the bare (lattice) QED coupling constant. We conjecture that this is the critical point of the chiral symmetry breaking phase transition in QED. Non-perturbative chiral symmetry breaking is then studied in the strong coupling limit. The discrete remnant of chiral symmetry that remains on the lattice is spontaneously broken, and the ground state to lowest order in the strong coupling expansion corresponds to the classical ground state of the two-dimensional spin one-half Heisenberg antiferromagnet.Comment: 30 pages, UFIFT-HEP-92-1

Mutations in DCC cause isolated agenesis of the corpus callosum with incomplete penetrance

Brain malformations involving the corpus callosum are common in children with developmental disabilities. We identified DCC mutations in four families and five sporadic individuals with isolated agenesis of the corpus callosum (ACC) without intellectual disability. DCC mutations result in variable dominant phenotypes with decreased penetrance, including mirror movements and ACC associated with a favorable developmental prognosis. Possible phenotypic modifiers include the type and location of mutation and the sex of the individual