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Upcoming Events

 

Colloquium

Topic:

Used Nuclear Fuel - Past, Present, and Future

Date:

29.01.18

Time:

16:15

Place:

H6

Guest:

Dr. Maik Stuke

Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) gGmbH

Abstract:

After a short introduction and overview of the company GRS I will focus on the past, present, and future of nuclear fuel used in German nuclear reactors. A summary of the origin and composition of different types of used nuclear fuel will be followed by an overview of the current situation and future plans of storage. This includes an overview of the foreseen steps until a final repository. I summarize my talk by discussing some open scientific questions.

Contact person:

D. Schwarz

Colloquium Mathematical Physics

Topic:

Mesoscopic eigenvalue correlations of random matrices

Date:

01.12.17

Time:

16:00

Place:

V2-210/216

Guest:

Antti Knowles

University of Geneva

Abstract:

Ever since the pioneering works of Wigner, Gaudin, Dyson, and Mehta, the correlations of eigenvalues of large random matrices on short scales have been a central topic in random matrix theory. On the microscopic spectral scale, comparable with the typical eigenvalue spacing, these correlations are now well understood for Wigner matrices thanks to the recent solution of the Wigner-Gaudin-Dyson-Mehta universality conjecture. In this talk I focus on eigenvalue density-density correlations between eigenvalues whose separation is much larger than the microscopic spectral scale; here the correlations are much weaker than on the microscopic scale. I discuss to what extent the Wigner-Gaudin-Dyson-Mehta universality remains valid on such larger scales, for Wigner matrices and random band matrices.

Contact person:

G. Akemann

Seminar High Energy Physics

Topic:

Novel Critical Behavior: From Spin Systems to Bird Swarms

Date:

23.01.18

Time:

14:15

Place:

D6-135

Guest:

Helmut Satz

Bielefeld

Abstract:

Twenty years ago, Tam´as Vicsek and collaborators introduced “a novel type of dynamics to investigate self-ordered motion of particles with biologically motivated interaction”. The model is a generalized spin system, proposed to account for the swarm formation of birds; the birds’ velocities become the spins. The resulting two-dimensional spin system has continuous rotational symmetry, but because of dynamical features it leads to spontaneous symmetry breaking and a phase transition to a state of long-range order in both one and two dimensions. It has become of considerable interest in different areas of statistical physics and continues to pose challenging problems.

Contact person:

H. Satz

Seminar Condensed Matter

Topic:

Finite-temperature dynamics using matrix product states

Date:

26.01.18

Time:

14:15

Place:

V2-205

Guest:

Salvatore Manmanna

Universität Göttingen

Abstract:

Contact person:

Jürgen Schnack

Seminar Mathematical Physics

Topic:

Eigenvector-related correlation functions and their connection with generalized chiral random matrix ensembles with a source

Date:

11.01.18

Time:

16:00

Place:

D5-153

Guest:

Jacek Grela

LPTMS Université Paris-Sud

Abstract:

We will introduce eigenvector-related correlation functions, discuss briefly their significance in dynamical Ginibre ensemble [1,2] and present asymptotic results in the large matrix size limit. Motivated by recent work [3] on joint eigenvector-eigenvalue correlation function valid for finite matrix size N in the complex and real Ginibre Ensembles, we study integrable structure of a certain generalized chiral Gaussian Unitary Ensemble with a source [4]. This model can be also interpreted as a deformation of the complex Ginibre Ensemble with an external source with additional determinant term. We present compact formulas for the characteristic polynomial, inverse characteristic polynomial and the kernel. In the case of a special source, we calculate asymptotics in the joint "bulk-edge" regime of all aforementioned objects and show their Bessel-type behaviour. References: [1] ''Dysonian dynamics of the Ginibre ensemble'', Z. Burda, J. Grela, M. A. Nowak, W. Tarnowski, P. Warcho?, Phys. Rev. Lett. 113, 104102 (2014) [2] ''Unveiling the significance of eigenvectors in diffusing non-hermitian matrices by identifying the underlying Burgers dynamics'', Z. Burda, J. Grela, M. A. Nowak, W. Tarnowski, P. Warcho?, Nucl. Phys. B 897, 421 (2015) [3] ''On statistics of bi-orthogonal eigenvectors in real and complex Ginibre ensembles: combining partial Schur decomposition with supersymmetry'', Y. V. Fyodorov, arXiv:1710.04699 [4] ''On characteristic polynomials for a generalized chiral random matrix ensemble with a source", Y. V. Fyodorov, J. Grela, E. Strahov, arXiv:1711.07061

Contact person:

Gernot Akemann

Seminar AG Zufallsmatrizen

Topic:

Exploring the boundaries of universality for Gaussian perturbations of Hermitian matrices

Date:

24.01.18

Time:

14:15

Place:

V3-201

Guest:

Thorsten Neuschel

University Catholique de Louvain

Abstract:

We explore the boundaries of sine kernel universality for the eigen- values of Gaussian perturbations of large deterministic Hermitian ma- trices. Equivalently, we study for deterministic initial data the time after which Dyson's Brownian motion exhibits sine kernel correlations. We explicitly describe this time span in terms of the limiting density and rigidity of the initial points. This is joint work with Tom Claeys and Martin Venker.

Contact person:

Gernot Akemann



  • @ 2008 Uni Bielefeld
  • | Letzte Änderung: 23.11.2011
  •  Olaf Kaczmarek
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