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

Correlation effects in a non-reciprocal Ising model

Kontakt: Peter Sollich

02.05.2024

Theoretische Physik

Seminar Statistical Physics

Juliana Caspers

Nonlinear Langevin equation for a driven probe

Kontakt: Peter Sollich

09.05.2024

Theoretische Physik

Seminar Statistical Physics

No seminar today

No seminar today

Kontakt: Peter Sollich

16.05.2024

Theoretische Physik

Seminar Statistical Physics

Felix Tippner

Decoding sample-to-sample fluctuations in the time-ordering of non-Markovian sample paths.

Kontakt: Peter Sollich

23.05.2024

Theoretische Physik

Seminar Statistical Physics

Srikanth Sastry

Yielding behaviour of active amorphous solids

Kontakt: Peter Sollich

30.05.2024

Theoretische Physik

Seminar Statistical Physics

Muhittin Mungan

Self-Organization and Memory in Driven Disordered Systems -- Dead or Alive

Kontakt: Peter Sollich

13.06.2024

Theoretische Physik

Seminar Statistical Physics

Lars Stutzer

Stochastic Calculus Approach to Thermodynamics of Jump Processes

Kontakt: Peter Sollich

20.06.2024

Theoretische Physik

Seminar Statistical Physics

Reimer Kuehn

Level-Set Percolation of Gaussian Free Fields on Complex Networks

Kontakt: Peter Sollich

27.06.2024

Theoretische Physik

Seminar Statistical Physics

Wade Hodson

Thermophoresis of a tracer particle coupled to a nonequilibrium harmonic medium

We investigate the transport of a tracer particle embedded in a medium with a position-dependent temperature. The model for the medium consists of a chain of harmonic oscillators, in which a temperature gradient is established by connecting each particle to its own stochastic heat reservoir. We then couple a tracer to this medium via a potential. Under these conditions, we find that the tracer preferentially diffuses in one direction due to the temperature gradient, a phenomenon known as thermophoresis. In this talk, I will focus on the dynamics of this model in the Markovian limit, when the dynamics of the medium are much faster than those of the tracer. In this limit, we are able to coarse-grain over the medium’s degrees of freedom to obtain a Langevin equation for the tracer, with a potential of mean force, a damping coefficient, and a diffusion coefficient which can be evaluated in the low-temperature regime. I will discuss the features of this low-temperature Langevin equation, with a particular interest in the parameter regimes where the tracer can potentially exhibit negative thermophoresis, in which the tracer diffuses preferentially towards higher temperatures.

Kontakt: Peter Sollich

04.07.2024

Theoretische Physik

Seminar Statistical Physics

Mike Chatzittofi

Nonlinear response theory of molecular machines

pre-print https://arxiv.org/pdf/2405.14011

Kontakt: Peter Sollich

11.07.2024

Theoretische Physik

Seminar Statistical Physics

Jacopo Romano

Defect motion from passive to driven systems

Kontakt: Peter Sollich