Effective string models for Lattice Gauge Theories

by Michele Caselle (Università di Torino)

Monday 31 Mar 2014, 16:00 → 18:00 Europe/Rome

Aula Conversi (Dipartimento di Fisica - ed. G. Marconi)

The interquark potential of whatever confining gauge theory in D space-time dimensions can be described, at large quark separation, by an effective string theory. Recently two important advances improved our understanding of this effective theory. First, it was realized that the form of the effective action is strongly constrained by the requirement of the Lorentz invariance of the gauge theory, which is spontaneously broken by the formation of a long confining flux tube in the vacuum. This constraint is strong enough to fix uniquely the first few subleading terms of the action which turn out to coincide with those of the Nambu-Goto string theory. Second, it was understood how to obtain the  exact Nambu-Goto spectrum by a suitable integrable perturbation of the 2d c=1 Conformal Field Theory. In this talk we first review the general implications of these two results for Lattice Gauge Theories and then, as a test of the power of these methods, use them to construct the first few boundary corrections to the effective string action. Finally, as a side application of effective string models, we discuss a new approach to the evaluation of glueball masses in finite temperature Lattice Gauge Theories.