Würzburg Seminar on Quantum Field Theory and Gravity

Anomalies can give rise to long lived modes, significantly altering the dynamics of near equilibrium systems. We will consider magnetic black branes in the low temperature limit and argue that, in the presence of a large Chern–Simons coupling, modes with arbitrarily small decay rates generically appear — independent of the matter content of the theory. This universality suggests that such modes could serve as experimentally accessible signatures of anomalies in condensed matter systems. I will also discuss possible connections between these excitations — including a fully backreacted analysis — and (holographic) time crystals, i.e., stable, time-periodic solutions to the bulk equations of motion that spontaneously break time translation symmetry.