Confining strings in a gapless phase
by
1/1-2 - Aula "C. Voci"
Dipartimento di Fisica e Astronomia - Edificio Marzolo
Confining string excitations are probably the most intriguing features of 4d gauge theories. In standard settings, such theories are expected to be gapped, and the dynamics of confining strings can be described, in the limit where they are much longer than the inverse gap, through the use of effective string theory. However, there are also interesting situations in which the bulk theory remains gapless while still exhibiting confinement. In such cases, the dynamics of confining strings require a more careful treatment. Motivated by the example of four-dimensional adjoint QCD and its conjectured infrared phase, I will present a four-dimensional infrared effective theory in which these strings can be studied perturbatively. I will then compute some of their observables explicitly, emphasizing the key differences (and similarities) from the conventional gapped case.