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Aktuelle Veranstaltungen

 

Kolloquium

Thema:

Antrittsvorlesung tba

Datum:

14.01.19

Uhrzeit:

15:15

Ort:

H6

Vortragender:

Prof. Dr. Sören Schlichting

Universität Bielefeld

Inhalt:

Ansprechpartner:

Dekan

Kolloquium Mathematische Physik

Thema:

tba

Datum:

01.02.19

Uhrzeit:

16:15

Ort:

U2-228

Vortragender:

Martin Zirnbauer

University of Cologne

Inhalt:

Ansprechpartner:

G. Akemann

Seminar Hochenergiephysik

Thema:

Extracting topology from lattice QCD near Tc

Datum:

18.12.18

Uhrzeit:

14:15

Ort:

D6-135

Vortragender:

Rasmus Larsen

BNL, Upton, NY, USA

Inhalt:

We report our study on the properties of the topological structures present in the QCD medium around the critical temperature Tc. We use dynamical domain wall fermion configurations on lattices of size $32^3x8$ and detect the topological structures through the zero modes of the overlap operator. We explicitly show that the properties of the zero modes of the QCD Dirac operator agrees well with that of calorons with non-trivial holonomy. Different profiles of the zero modes are observed, and when we change the boundary condition of the overlap operator in the temporal direction, the zero mode moves to another location . All of this indicates the presence of instanton-dyons in the hot QCD medium around Tc, where the distance between dyons control the shape and extent of the zero modes.

Ansprechpartner:

Ch. Schmidt

Seminar Kondensierte Materie

Thema:

tba

Datum:

24.01.19

Uhrzeit:

14:15

Ort:

D5-153

Vortragender:

Oliver Waldmann

Universitaet Freiburg

Inhalt:

Ansprechpartner:

Jürgen Schnack

Seminar Mathematische Physik

Thema:

Eigenvector correlations for quaternionic Ginibre ensembles

Datum:

20.12.18

Uhrzeit:

15:00

Ort:

D5-153

Vortragender:

Yanik-Pascal Foerster

Bielefeld University

Inhalt:

Non-Hermitian matrices feature distinct left and right eigenvectors, neither of which forms an orthonormal system, while both sets together satisfy bi-orthogonality. It was suggested by Chalker and Mehlig in 2000 to study the statistics of eigenvector overlaps, in particular their correlation functions. For complex Ginibre ensembles they obtained one-point and two-point eigenvector correlations via Schur decomposition for finite $N$ as well the corresponding limiting behaviour. Recently, several works by Bourgade, Dubach, and Fyodorov have brought new attention to the topic, establishing the results for the complex ensembles rigorously and deriving similar results for the real and quaternionic cases. In this talk, I will present how Chalker's and Mehlig's approach is applied to quaternionic Ginibre matrices, leading to correlation functions that can be written compactly in terms of Pfaffian determinants. Given one purely imaginary eigenvalue, the formulae simplify, enabling us to derive the limiting behaviour near the origin of the complex plane. Finally, I will report on the limiting behaviour for one-point and two-point correlation functions for eigenvalues inside the bulk, which turn out to be identical to the limits in the real and complex cases.

Ansprechpartner:

Gernot Akemann

Seminar AG Zufallsmatrizen

Thema:

The level spacing distribution at the hard edge

Datum:

28.11.18

Uhrzeit:

16:15

Ort:

V3-201

Vortragender:

Valentin Gorski

Bielefeld University

Inhalt:

The level spacing distribution in the bulk of a spectrum is approximately given by the Wigner surmise. Yet, at the hard and the soft edge one can expect strong deviations from these laws. Using the orthogonal polynomial method we derive the spacing distribution of the smallest two singular values of the chiral Gaussian unitary ensemble (chGUE) at finite matrix dimension with additional characteristical polynomials in the weight. The number of these polynomials represents the number of flavors (types of quarks) in the physical system. This ensemble approximates the Euclidean Dirac operator in Quantum Chromodynamics (QCD). In my talk, I will report on the behavior of the level spacing distribution in this particular setting.

Ansprechpartner:

Gernot Akemann



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  • | Letzte Änderung: 23.11.2011
  •  Olaf Kaczmarek
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