Abstract I review some aspects of BPS magnetic monopoles and of electric-magnetic duality in theories with arbitrary gauge groups. When the symmetry is maximally broken to a U(1)r subgroup, all magnetically charged configurations can be understood in terms of r species of massive fundamental monopoles. When the unbroken group has a non-Abelian factor, some of these fundamental monopoles become ...

The path integral for randomly forced incompressible fluids is shown to have an underlying Becchi-Rouet-Stora (BRS) symmetry as a consequence of Galilean invariance. This symmetry must be respected to have a consistent generating functional, free from both an overall infinite factor and spurious relations amongst correlation functions. We present a procedure for respecting this BRS symmetry, ak...

We show that the controversies on the gauge dependence and the infrared singularity emerged in the generalized factorization approach for nonleptonic heavy meson decays within the framework of the operator product expansion can be resolved by perturbative QCD factorization theorem. Gauge invariance of the decay amplitude is maintained under radiative corrections by assuming onshell external qua...

The spin-field interaction is considered, in the context of the gauge fields/string correspondence, in the large ’t Hooft coupling limit. The latter can be viewed as a WKB-type approximation to the AdS/CFT duality conjecture. Basic theoretical objects entering the present study are (a) the Wilson loop functional, on the gauge field side and (b) the sigma model action for the string propagating ...

The Global Color-symmetry Model of QCD is extended to deal with a background electromagnetic field and the associated conserved current is identified for composite ¯ qq pion modes of the model. Although the analysis is limited to tree level in the bilocal fields that bosonize the model, the identified photon-pion vertex produces the charge form factor associated with ladder Bethe-Salpeter pion ...

We consider the ordinary and noncommutative Dirac-Born-Infeld theories within the open string σ-model. First, we propose a renormalization scheme, hybrid point splitting regularization, that leads directly to the Seiberg-Witten description including the two-form Φ. We also show how such a form appears within the standard renormalization scheme just by some freedom in changing variables. Second,...

We study planar gluon scattering amplitudes and Wilson loops in non-commutative gauge theory. Our main results are: 1. We find the map between observables in non-commutative gauge theory and their holographic dual. In that map, the region near the boundary of the gravitational dual describes the physics in terms of T-dual variables. 2. We show that in the presence of a large magnetic background...

We construct a calculable model of electroweak symmetry breaking in which the Higgs doublet emerges from the meta-stable SUSY breaking sector as a pseudo Nambu-Goldstone boson. The Higgs boson mass is further protected by the little Higgs mechanism, and naturally suppressed by a two-loop factor from the SUSY breaking scale of 10 TeV. Gaugino and sfermion masses arise from standard gauge mediati...

The landscape of string/M theory is surveyed over a large class of type IIB flux compactification vacua. We derive a simple formula for the average size of the gauge group rank on the landscape under assumptions that we clearly state. We also compute the rank under the restriction of small cosmological constant, and find a slight increase. We discuss how this calculation could impact proton sta...

We consider the renormalisation of the Fayet-Iliopoulos D-term in a softly-broken supersymmetric gauge theory with a non-simple gauge group containing an abelian factor, and present the associated β-function through three loops. We also include in an appendix the result for several abelian factors. We specialise to the case of the minimal supersymmetric standard model (MSSM), and investigate th...