Programma 11 Aprile
Teorie di Campo e di Corda (F. Gliozzi)
Abstract:After a general introduction on the present status of the gauge/string correspondence, we present several AdS/CFT checks for a newly found family of N=1 dual pairs, and also discuss interesting non-conformal deformations of the former. The corresponding theories display non-trivial RG-flows for which a dual supergravity description is available, but a runaway behavior in the deep IR. Hence, we finally comment on the possibility (and the problems) of finding, in this specific context, suitable string duals of QCD-like theories.
Abstract: We illustrate different mechanisms of color confinement relating them to properties of the QCD vacuum and discussing evidence coming from lattice QCD simulations.
Abstract:The Nambu-Goto string in d dimensions is considered as an effective model of physical situations dominated by the d.o.f. of fluctuating strings, such as Polyakov loop correlators in confining gauge theories, or fluid interfaces in statistical systems. By using standard covariant quantization, it is possible to integrate the NG partition function over the world-sheet, getting an exact expressions in dependence of the geometry of the surface spanned by the string in target space. This expressions resums the perturbative expansion of the functional integral approach in the "physical gauge" and compares very well to avaliable MC data in the regime of sufficietly large sizes where the conformal anomaly for d < 26 has negligible effects.
Abstract: Usando il modello sigma nonlineare come paradigma, viene proposto un metodo di rinormalizzazione e vengono illustrate alcune proprieta' dello sviluppo perturbativo per teorie "non rinormalizzabili"
Abstract: I summarize the current theoretical knowledge in lattice supersymmetry with special emphasis on recent results in the framework of N=1 supersymmetric Yang Mills theory, Wess-Zumino model and Yang-Mills theory with extended supersymmetries.
Abstract: I discuss a field theory on the noncommutative plane endowed with the Moyal product. The symmetry is to be understood in the quantum sense, in that while the commutation relations are unchanged and form two copies of the Virasoro algebra, the coaction id deformed by terms depending on the noncommutativity parameter theta. We then quantize the theory. We show that to satisfy the Kac-Moody current algebras (which imply conformal invariance) we must impose a deformation of the commutation relations between the creation and annihilation operators of the theory.