1/1-2 - Aula "C. Voci" (Dipartimento di Fisica e Astronomia - Edificio Marzolo)
1/1-2 - Aula "C. Voci"
Dipartimento di Fisica e Astronomia - Edificio Marzolo
32
Description
Effective Field Theories (EFTs) find applications in diverse branches of physics, in particular, particle physics, cosmology, and condensed matter systems. Thus narrowing down the space of `consistent' EFTs is an important and useful exercise. In this talk, I will discuss causality and unitarity constraints on dimension 6 and dimension 8 Gluon field strength operators in QCD. In particular, I'll compare the two different ways to get these bounds: the "IR avatar" - where one demands that the speed of fluctuations about any non-trivial background should not exceed the speed of light, and the "UV avatar" - where one uses dispersion relation for 2→2 scattering in the forward limit. Finally, I will mention an interesting non-relativistic example where the IR avatar (i.e., subluminality) produces a stronger bound than the UV avatar (i.e., S-matrix positivity).