# Generalized global symmetries, Goldstone modes, and hydrodynamics

03.11.2017 14:15 – 15:15

In quantum field theory, conserved particle numbers are associated with ordinary global symmetries. However, many theories can also possess a conserved density of extended objects such as strings, branes, etc — the generalized symmetry principle associated with such conservation laws is just as powerful as that for ordinary symmetries but has only recently been systematically explored. I will explain some of the resulting insights, discussing the classification of low-energy phases and discussing the emergence of gapless Goldstone modes when they are spontaneously broken. Such a symmetry also plays an important role in characterizing the long-distance physics of familiar Maxwell electrodynamics in four dimensions; as an application, I will discuss the realization of this symmetry at finite temperature and provide a reformulation of magnetohydrodynamics from the point of view of symmetry and effective field theory.

### Lieu

Bâtiment: Ecole de Physique

Auditoire Stuckelberg

### Organisé par

Département de physique théorique### Intervenants

Nabil Iqbal, Durhamentrée libre