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Kolloquium

Thema:

Dynamics of ions under confinement: Ionic liquids moving through regular nanoporous frameworks

Datum:

27.06.22

Uhrzeit:

16:15

Ort:

H6

Vortragender:

PD Dr. Lars Heinke

Karlsruhe Institute of Technology, Institute of Functional Interfaces

Inhalt:

Transport phenomena of molecules and ions inside porous materials are crucial for various fields, ranging from energy storage and transformation to molecular separation. In many advanced energy storage devices like supercapacitors charged molecules are confined in small pores. There, nanoconfinement effects may change the ion properties fundamentally. For detailed insights, the dynamic properties of molecular cations and anions, forming ionic liquids (ILs), confined in the nanopores of crystalline metal-organic frameworks (MOFs) are explored. Such well-defined model systems allow a precise understanding of the ion dynamics under confinement and unveil unexpected effects like strong guest-guest and host-guest correlations. In the presentation, these confinement effects of the ion dynamics are discussed.

Ansprechpartner:

A. Gölzhäuser

Kolloquium Mathematische Physik

Thema:

Vertex Algebras for 2- and 4-Dimensional Conformal Field Theories

Datum:

01.07.22

Uhrzeit:

16:15

Ort:

D5-153

Vortragender:

Sven Möller

Universität Hamburg

Inhalt:

Vertex (operator) algebras axiomatise 2-dimensional conformal field theories in physics. They were introduced in the 1980s to explain mysterious connections between number and representation theory (monstrous moonshine). Not long ago, they were also shown to capture certain aspects of 4-dimensional superconformal field theories. In this talk I will describe recent classification results for holomorphic vertex algebras of central charge 24 by means of certain modular forms (vector-valued Eisenstein series). Moreover, I will sketch classification problems arising in the context of 4-dimensional field theories.

Ansprechpartner:

G. Akemann

Seminar Hochenergiephysik

Thema:

Axion warm inflation and reheating

Datum:

30.06.22

Uhrzeit:

14:15

Ort:

D6-135

Vortragender:

Simona Procacci

Universität Bern

Inhalt:

After introducing a simple homogeneous and isotropic inflationary model, we add interactions via an axion-like decay to Yang-Mills gauge bosons. As these rapidly thermalize, the friction felt by the inflaton field is increased by non-Abelian “strong sphalerons”. The resulting self-amplifying process can efficiently heat up the system. Such a reheating period may produce gravitational waves via hydrodynamic fluctuations and particle collisions.

Ansprechpartner:

D. Bödeker

Seminar Kondensierte Materie

Thema:

Das Perzeptron: Grundbaustein neuronaler Netze und kuenstlicher Intelligenz

Datum:

30.06.22

Uhrzeit:

14:15

Ort:

D5-153

Vortragender:

Paul Angelike

Universität Bielefeld

Inhalt:

Ansprechpartner:

Peter Reimann

Seminar Mathematische Physik

Thema:

Many-particles diffusing with resetting: study of the large-deviation properties of the flux distribution

Datum:

05.05.22

Uhrzeit:

16:00

Ort:

D5-153

Vortragender:

Costantino Di Bello

Inhalt:

In this paper we studied a model of noninteracting particles moving on a line following a common dynamics. In particular we considered either a diffusive motion with Poissonian resetting, and a run-and-tumble motion with Poissonian resetting. We were interested in studying the distribution of the random variable $Q_t$ defined as the flux of particles through origin up to time $t$. We used the notation $P(Q,t)$ to identify the probability $\mathbb{P}\{Q_t=Q\}$. We considered particles initially located on the negative half line with a fixed density $\rho$. In fully analogy with disordered systems, we studied both the annealed and the quenched case for initial conditions. In the former case we found that, independently from the specific dynamics, $P_\mathrm{an}(Q,t)$ has a Poissonian shape; while in the latter case, for what concerns the diffusive dynamics with resetting, the large deviation form of the quenched distribution reads $P_\mathrm{qu}(Q,t)\sim \exp\left[-r^2t^2 \Psi_\mathrm{diff}\left(\dfrac{Q}{\rho t}\right)\right]$ with the large deviation function $\Psi_\mathrm{diff}(x)$ exhibiting a discontinuity in the third derivative, hence aiming, despite the simplicity of the model, at the exhistence of a dynamical phase transition. The quenched distribution for the run-and-tumble dynamics, instead, does not exhibit any kind of phase transition. Importance sampling Monte Carlo simulations were performed to prove the analytical results. References: Current fluctuations in noninteracting run-and-tumble particles in one dimension Tirthankar Banerjee, Satya N. Majumdar, Alberto Rosso, and Grégory Schehr, Phys. Rev. E 101, 052101 https://doi.org/10.1103/PhysRevE.101.052101 Current Fluctuations in One Dimensional Diffusive Systems with a Step Initial Density Profile B. Derrida and A. Gerschenfeld, J. Stat. Phys. 137, 978 (2009) https://doi.org/10.1007/s10955-009-9830-1

Ansprechpartner:

Gernot Akemann

Seminar AG Zufallsmatrizen

Thema:

tba

Datum:

29.06.22

Uhrzeit:

09:00

Ort:

ZOOM / Konferenzschaltung

Vortragender:

Dario Rosa

Daejeon and Stony Brook

Inhalt:

Ansprechpartner:

Gernot Akemann



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