Institute for Theoretical Physics

25/04/24

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

25/04/24

Theoretische Physik

Seminar Statistical Physics

Kristian Blom

Correlation effects in a non-reciprocal Ising model

Kontakt: Peter Sollich

02/05/24

Theoretische Physik

Seminar Statistical Physics

Juliana Caspers

tbc

Kontakt: Peter Sollich

09/05/24

Theoretische Physik

Seminar Statistical Physics

No seminar today

No seminar today

Kontakt: Peter Sollich

16/05/24

Theoretische Physik

Seminar Statistical Physics

Felix Tippner

tba

Kontakt: Peter Sollich

23/05/24

Theoretische Physik

Seminar Statistical Physics

Srikanth Sastry

tba

Kontakt: Peter Sollich

30/05/24

Theoretische Physik

Seminar Statistical Physics

Muhittin Mungan

tba

Kontakt: Peter Sollich

20/06/24

Theoretische Physik

Seminar Statistical Physics

Reimer Kuehn

tba

Kontakt: Peter Sollich

26/06/24

Theoretische Physik

Seminar Statistical Physics

Wade Hodson

tba

Kontakt: Peter Sollich

04/07/24

Theoretische Physik

Seminar Statistical Physics

Jacopo Romano

tba

Kontakt: Peter Sollich

11/07/24

Theoretische Physik

Seminar Statistical Physics

Mike Chatzittofi

tba

Kontakt: Peter Sollich