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Aktuelle Veranstaltungen

 

Kolloquium

Thema:

Nuts to soup: QCD in the Regge limit, the Color Glass Condensate, and the approach to thermalization in heavy-ion collisions

Datum:

10.12.18

Uhrzeit:

16:15

Ort:

H6

Vortragender:

Prof. Dr. Raju Venugopalan

Brookhaven National Laboratory

Inhalt:

It was proposed about 25 years ago that the Regge limit of QCD could be described by a many-body classical effective field theory now known as the Color Glass Condensate (CGC). This conjecture was prompted by the phenomenon of gluon saturation, whereby many-body gluodynamics leads to the emergence of a semi-hard scale that screens color charge in the infrared. In the first part of this talk, we will introduce the concepts of the CGC effective theory, emphasizing a paradigm shift in what constitutes fundamental degrees of freedom in the Regge limit. We shall also outline a color memory effect in the CGC which bears an exact analogy to the gravitational memory effect that could be discovered by LIGO in the near future. This correspondence in turn prompts one to speculate that asymptotic BMS-like symmetries analogous to those in gravity may also apply in QCD's Regge limit, leading to novel insight into how pions form "soft hair" on glue. In the second part of the talk, we discuss how the CGC provides an ab initio picture of thermalization and hydrodynamics in ultrarelativistic heavy-ion collisions. We focus on the discovery of a pre-thermal turbulent attractor, its topological properties, and a remarkable universality between this attractor and cold atomic gases prepared with the same boundary conditions.

Ansprechpartner:

F. Karsch/TR211

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:

QCD at finite temperature and chemical potential from Dyson-Schwinger equations

Datum:

11.12.18

Uhrzeit:

14:15

Ort:

D6-135

Vortragender:

Christian Fischer

Univ. Giessen

Inhalt:

We review results for the phase diagram of QCD, the properties of quarks and gluons and the resulting properties of strongly interacting matter at finite temperature and chemical potential. We discuss the progress in this field from a theoretical perspective, focusing on non-perturbative QCD as encoded in the functional approach via Dyson-Schwinger and Bethe-Salpeter equations. We discuss various aspects associated with the variation of the quark masses and assess recent results for the QCD phase diagram including the location of a putative critical end-point for $N_f=2+1$ and $N_f=2+1+1$.

Ansprechpartner:

Ch. Schmidt

Seminar Kondensierte Materie

Thema:

Equilibration of expectation values for statically and dynamically generated initial conditions

Datum:

14.12.18

Uhrzeit:

14:15

Ort:

D2-240

Vortragender:

Christian Bartsch

Universität Osnabrück

Inhalt:

We investigate dynamical equilibration of expectation values in closed quantum systems for realistic non-equilibrium initial states. For statically generated initial states we find that the long time expectation values depend on the initial expectation values if eigenstate thermalization is violated. An analytical expression for the deviation from the expected ensemble value is derived for small displacements from equilibrium based on linear response theory. Analogous derivations show that this deviation vanishes for dynamically generated initial states, at least within the linear response regime. Additional numerics for magnetization and energy equilibration in an asymmetric anisotropic spin-1/2-ladder illustrate the behavior beyond linear response for both cases.

Ansprechpartner:

Peter Reimann

Seminar Mathematische Physik

Thema:

tba

Datum:

20.12.18

Uhrzeit:

15:00

Ort:

D5-153

Vortragender:

Yanik-Pascal Foerster

Bielefeld University

Inhalt:

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



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