Institut für Theoretische Physik

08.04.2024

Theoretische Physik

Quantenfeldtheorie (Forschungsseminar M.Phy.412)

Emre Artan

Representation theory and anomalies

Kontakt: K.-H. Rehren

11.04.2024

Theoretische Physik

Seminar Statistical Physics

Aritra Bose

Anomalous fluctuations in active matter condensate

Kontakt: Peter Sollich

18.04.2024

Theoretische Physik

Seminar Statistical Physics

Gabriel Knotz

Mean Back Relaxation for Position and Densities

Kontakt: Peter Sollich

25.04.2024

Theoretische Physik

BornHilbertSeminar

Ezio Vasselli

Superselection sectors and the cohomology of Haag-Kastler nets

Superselection sectors, whose analysis is one of the major achievements of local quantum physics, have been approached in several ways, depending on the spacetime and the criterion of interest. In the present talk we give a general scheme to define sectors, independent of the above choices. The input is given by a family of spacetime regions, where the sectors are supposed to be localized, and a factorial Haag-Kastler net fulfilling relative Haag duality on such regions. The output is a superselection structure localized on regions of the given family, covariant with respect to spacetime symmetries preserving the regions themselves.
Our scheme is based on the notion of covariant cohomology of a Haag-Kastler net, and covers all the types of regions previously considered both in (4d) Minkowski space and in curved spacetimes. Moreover, it allows detection of topological phenomena as the Aharonov-Bohm effect. Hypercones (used by Buchholz and Roberts in the massless case) fit our scheme, yet the energetic aspects are the subject of a work in progress with D. Buchholz.
Joint work with F. Ciolli and G. Ruzzi http://arxiv.org/abs/2306.08449

Kontakt: K.-H. Rehren

25.04.2024

Theoretische Physik

Seminar Statistical Physics

Kristian Blom

tba

Kontakt: Peter Sollich

02.05.2024

Theoretische Physik

Seminar Statistical Physics

Juliana Caspers

tbc

Kontakt: Peter Sollich