Here you find the upcoming and past talks and colloquia. The colour code and abbreviations:
Seminar of the Institute Quantum Theory Seminar General Relativity Seminar
Video seminar of the SFB Colloquium of the Faculty Other Talks
Seminar of Research Training Group

HS: Hörsaal (Lecture Hall), SR: Seminarraum (Seminar room), URZ Universitätsrechenzentrum (Computer Center)

Upcoming Talks

Mon, 2016-05-02 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Wie entstanden die ersten festen Körper im jungen Sonnensystem?
Prof. Dr. Jürgen Blum, TU Braunschweig
Tue, 2016-05-03 16:15(SR 5, HHW 4)
Hawking Radiation
Prof. Dr. Andreas Wipf, TPI Jena
Wed, 2016-05-11 16:15
Nonequilibrium entropy production for open quantum systems
Prof. Eric Lutz (FAU Erlangen)


Entropy production is a fundamental quantity of nonequilibrium thermodynamics. We here discuss exact microscopic expressions for the nonequilibrium entropy production of closed and open quantum systems that are driven arbitrarily far from equilibrium, in particular beyond the linear response regime. We additionally consider the entropy production rate, which provides information about the speed of nonequilibrium processes, and show that they are bounded from above for quantum systems. The connection with the notion of quantum speed limit is addressed.
Thu, 2016-05-12 14:15
Spontaneous breaking of Lorentz symmetry in QED3
Dr. Lukas Janssen (TU Dresden)

Abstract: The phase diagram of quantum electrodynamics in three space-time dimensions as a function of fermion flavor number N exhibits two well-known phases: at large N > Nc1 the system is in a conformal gapless state, while for small N < Nc2 the fermions are expected to develop a dynamical mass due to spontaneous chiral symmetry breaking. Using epsilon expansion near the lower critical dimension of two, in combination with the recent results on the generalization of the F theorem to continuous dimension, we show that Nc1 > Nc2. There is therefore an intermediate range of values of N at which a third phase is stabilized. We demonstrate that this phase is characterized by spontaneous breaking of Lorentz symmetry, in which a composite vector boson field acquires a vacuum expectation value with the fermions and the photon remaining massless.
Mon, 2016-05-23 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Prof. Dr. Christian Eggeling, Univ. of Oxford
Wed, 2016-05-25 16:15
Dr. Andre Sternbeck, TPI Jena
Thu, 2016-05-26 14:15
Prof. Dr. Martin Schaden, Rutgers University
Thu, 2016-06-02 14:15
reserved (Felix)
Wed, 2016-06-08 16:15(HS 2, Abbeanum)
Dual Foliation Formulations of General Relativity
or "how I learned to stop worrying and love coordinates"

by Dr. David Hilditch, TPI Jena

Abstract: When solving general relativity numerically for a given physical problem we must use a formulation of the field equations for which the resulting partial differential equation problem is well-posed. Building such a good formulation usually requires making a coordinate choice. This leads to the standard statement that `gauge freedom in general relativity is the choice of coordinates'. The
latter two facts have long bothered me, because one of the first lessons in relativity is that coordinates should in some sense not matter. In my talk I will explain the solution to my earlier confusion. Time permitting I will also describe ongoing work to exploit the solution for practical calculations.

Thu, 2016-06-09 14:15
Mon, 2016-06-13 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
X, Y, Z - Ein exotisches Hadronen-Alphabet
Prof. Dr. Klaus Peters, GSI Darmstadt
Mon, 2016-06-27 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Habilitationsvorstellung: Tailoring Light Fields with Silicon Hygens' Metasurfaces
Dr. Isabelle Staude, Abbe Center of Photonics, FSU Jena
Fri, 2016-07-01 16:15
Wed, 2016-07-06 16:15
Numbers and functions in quantum field theory
Dr. Oliver Schnetz, Univ. Erlangen

Quantum field theories describe the fundamental interactions between physical particles. Perturbation theory organizes quantum field theory calculations as expansions in Feynman graphs. Each Feynman graph stands for a multi-dimensional integral over a differential form which is a rational function with integer coefficients. We report on the mathematical structures of the numbers and functions which arise from these integrals. We also indicate how these structures can be used to perform (some) quantum field theory calculations to very high order.
Thu, 2016-07-07 14:15(SR 5, Helmholtzweg 4)
Tetraquarks from Lattice QCD
Prof. Dr. Marc Wagner, Univ. Frankfurt


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Past Talks

Talks from 2014-10-01 up to Today
Wed, 2016-04-27 16:15
Nonlinear evolution of perturbed anti-de Sitter spacetime
Dr. Piotr Bizon (Krakow)

Abstract: Dynamics of asymptotically AdS spacetimes is an interesting meeting point of fundamental problems in general relativity, PDE theory, theory of turbulence, and AdS/CFT correspondence. In my talk I will describe recent progress in understanding this problem, focusing on evidence for the instability of AdS spacetime.
Tue, 2016-04-26 17:15(HS 2, Helmholtzweg 5)
Disputation "Untersuchungen von rotierenden und geladenen Staubscheiben mit hochgenauen Näherungslösungen und der Grenzübergang zu Schwarzen Löchern"
Disputation of Martin Breithaupt
Tue, 2016-04-26 14:30(SR 5, Helmholtzweg 4)
Thermodynamics of higher spin black holes
Tim Nitzsche

Thu, 2016-04-21 16:00(Hörsaal 9, Carl-Zeiß-Str. 3)
Magnetic Vortices, vortex lattices and automorphic functions
Prof. Dr. Israel Michael Sigal, Univ. Toronto

I will review recent results concerning the Ginzburg - Landau equations. These equations were first developed to understand macroscopic behaviour of superconductors; later, together with their non-Abelian generalizations - the Yang-Mills-Higgs equations, they became a key part of the standard model in elementary particle physics. They also have found important applications in geometry and topology.

The Ginzburg - Landau equations have remarkable solutions, localized topological solitons, called the magnetic vortices in the superconductivity and the Nielsen-Olesen or Nambu strings in the particle physics, as well as extended ones, magnetic vortex lattices.

I will review the existence and stability theory of the vortex lattice solutions and how they relate to the modified theta functions appearing in number theory and algebraic geometry. Certain automorphic functions play a key role in the theory described in the talk.
Thu, 2016-04-21 14:15(SR 5, Helmholtzweg 4)
Critical scaling in the Large-N O(N) model and its possible connection to quantum gravity
Dr. Péter Mati (Budapest/Szeged)

The critical scaling of the large-N O(N) model in higher dimensions using the exact renormalization group equations will be discussed. Particular attention is paid to the case of d=5 where the scaling exponent of the correlation length has the value 1/3, which coincides with the scaling exponent of quantum gravity in one fewer dimensions. Convincing results show that this relation could be generalized to arbitrary number of dimensions above five. Some aspects of AdS/CFT correspondence will be also discussed.
Wed, 2016-04-20 10:15(HI Jena, Fröbelstieg 3)
QED in the infrared
Dr. Péter Mati (Budapest/Szeged)
Joint Seminar with Helmholtz Institute Jena

Infrared (IR) singularities in massless gauge theories are known since the foundation of quantum field theories. The root of this problem can be tracked back to the very definition of these long-range interacting theories such as QED. The IR catastrophe and its resolution by cancelling the divergences will be discussed. The Bloch-Nordsieck model provides the deep IR description of QED, and in its framework all the radiative corrections to the electron propagator can be fully summed, giving the infra-particle interpretation to the electron. This solution can be obtained by using the functional technique based on the Schwinger-Dyson equation with the aid of the Ward-Takahashi identities. At finite temperatures we use the Keldysh description, that will give a matrix structure to the equation. Again an analytic solution can be obtained for the exact spectral function. The finite temperature solution provides a natural explanation of IR finiteness.
Tue, 2016-04-19 16:15(SR 5, Helmholtzweg 4)
Thermodynamics in GR
Prof. Dr. Gernot Neugebauer, TPI Jena
Mon, 2016-04-11 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Habilitationsvorstellung: Verdrilltes Licht: Physik und Anwendungen
Dr. Marco Ornigotti, Institut für Angewandte Physik, FSU Jena
Thu, 2016-04-07 14:30(SR 5, Helmholtzweg 4)
Verteidigung Masterarbeit
Birger Böning
Mon, 2016-04-04 17:15(HS 1, Abbeanum)
First Observation of Gravitational Waves from a Binary Black Hole Merger
Prof. Dr. Bernd Brügmann, FSU Jena
Fri, 2016-03-11 16:15
Collapse of the Brill waves in a moving-puncture-like gauge (WIP)
Anton Khirnov


One of the open problems in numerical relativity is that of the critical collapse of gravitational waves into a black hole. Quite interestingly, it has been discovered that the supercritical Brill waves, a commonly used family of initial data, cannot be successfully evolved with the moving puncture gauge, popular for black hole simulations. In this talk, we present our work in progress on using a modification of the moving puncture gauge to evolve such data.
Fri, 2016-03-04 16:15(HS 2, Abbeanum)
Verteidigung der Masterarbeit
Anika Dathe
Thu, 2016-02-11 16:15(SR 5, Helmholtzweg 4)
The fate of Halpern-Huang directions
Dr. Alfio Bonanno (INAF, Catania)
Wed, 2016-02-10 14:15
Cosmological Implications of Quantum Quadratic Gravity
Dr. Alfio Bonanno (INFN Catania)
Mon, 2016-02-08 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Habilitationsvorstellung: Optische Signaturen des Quantenvakuums in starken elektromagnetischen Feldern
Dr. Felix Karbstein, FSU Jena
Thu, 2016-02-04 14:15
Nonperturbative renormalization group flow for scalar fields in de Sitter space
Dr. Maxime Guilleux, Univesite Paris Diderot
Wed, 2016-02-03 16:15
Thu, 2016-01-28 14:15
Phase diagram of an asymptotically free model through lattice dualization
Dr. Falk Bruckmann, Universität Regensburg
Wed, 2016-01-27 16:15(HS 2, Abbeanum)
Numerics and Astrophysics of Neutron Stars
Prof. Stephan Rosswog, Universität Stockholm
Tue, 2016-01-26 16:15(SR 5, Helmholtzweg 4)
Dr. Javier Rubio, Heidelberg
Mon, 2016-01-25 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Wie könnte man die Gravitation beeinflussen?
Prof. Dr. Martin Tajmar, TU Dresden
Thu, 2016-01-21 14:00
Higgs inflation and the cosmological frame debate
Dr. Christian Steinwachs, Universität Freiburg
Wed, 2016-01-20 16:15(HS 2, Abbeanum)
Binary Black holes: Numerical simulations and their applications
Prof. Harald Pfeiffer, Canadian Institute of Theoretical Astrophyiscs, University of Toronto
Thu, 2016-01-14 14:15
Worldsheet string theory in AdS/CFT: perturbation theory and beyond
Dr. Valentina Forini, HU Berlin

Abstract: It is discussed how the integrable structure underlying the AdS/CFT system and the cross-fertilization of established field-theretical tools to strings can be used to enhance our knowledge on
the string sigma model and thus the predictivity of the duality.
Tue, 2016-01-12 16:15
Monte Carlo Methods for Approximation Problems
Robert Kunsch
Mon, 2016-01-11 18:00(Aula der FSU)
Antrittsvorlesung: Predicting new materials and their properties with supercomputing
Prof. Dr. Silvana Botti, FSU Jena
Wed, 2016-01-06 16:15(HS 2, Abbeanum)
Conformal properties of the Schwarzschild-de Sitter spacetime
Dr. Juan Valiente-Kroon, School of Mathematical Sciences at Queen Mary, University of London

In this talk I will show how the asymptotic initial value problem for the conformal Einstein field equations, whereby one prescribes initial data on a spacelike hypersurface representing the conformal boundary, can be used to study various conformal aspects of the Schwarzschild-de Sitter spacetime. The analysis presented covers the subextremal, extremal and hyperextremal cases. The implications of this analysis for the study of nonlinear perturbations of members of the Schwarzschild-de Sitter family of spacetimes are discussed.
Tue, 2016-01-05 16:15(SR 5, Helmholtzweg 4)
Introduction to Information-Based Complexity (IBC)
Robert Kunsch
Fri, 2015-12-18 16:15
Lösung axialsymmetrischer Wellengleichungen in der Kerr-Metrik durch eine Laplacetransformations-Methode
Verteidigung der Masterarbeit
Jörg Dommaschk, FSU Jena
Thu, 2015-12-17 14:15
Maximally supersymmetric Yang--Mills-Theory on the lattice
Dr. David Schaich
Syracuse University
Wed, 2015-12-16 16:15(HS 2, Abbeanum)
Dr. Omar Zanusso (TPI, FSU Jena)
Thu, 2015-12-10 14:00
A holographic phase diagram of QCD and the critical point
Roman Yaresko (Helmholtz-Zentrum Dresden-Rossendorf)
Tue, 2015-12-08 16:15
From spectral functions to viscosity in the Quark-Gluon Plasma
Dr. Nicolai Christiansen, Universität Heidelberg
Mon, 2015-12-07 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Cosmic Matter in the Laboratory
Prof. Dr. Horst Stöcker, Universität Frankfurt
Fri, 2015-12-04 16:15(HS 2, Abbeanum)
Nichtlineare Wechselwirkungen ebener Gravitationswellen
Verteidigung der Masterarbeit von Marco Vockert
Thu, 2015-12-03 14:15(SR 5, Helmholtzweg 4)
The Overlap Dirac operator and its Application to the Quark Sector of QCD in Coulomb Gauge
Dr. Markus Pak (Uni Graz)
Fri, 2015-11-27 16:15
A New ADER-DG Scheme based on a Local Continuous Runge-Kutta Method
Verteidigung der Masterarbeit
Matthias Pilz, FSU Jena
Tue, 2015-11-24 16:15(SR 5, Helmholtzweg 4)
Towards quasicrystals in non-commutative spaces
Felix Pogorzelski


In 2011, Dan Shechtman was awarded the Nobel prize in chemistry for his discovery of physical quasicrystals. Via diffraction experiments, he observed in 1982 that for some materials, there are interference patterns whose symmetries are not compatible with crystallographic structures in three-dimensional space. This triggered the mathematical examination of those structures as Dirac combs over uniformly discrete point sets in Euclidean space.
In the past decades, mathematical diffraction theory evolved into a beautiful and rich research topic combining various disciplines such as functional analysis, fourier analysis and dynamical systems. One method to obtain a large class of interesting quasicrystals is via so-called cut-and-project schemes, introduced by Meyer in the 70s. This talk presents the basics of diffraction for cut-and-project schemes over locally compact abelian groups and describes how the theory can be extended to the non-commutative case.
This is joint work with Michael Björklund (Chalmers Göteborg) and
Tobias Hartnick (Technion Haifa).
Mon, 2015-11-23 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Carrier lifetime and diffusion constant: How to determine solar Cell material Proberties by time-resolved photoluminescence
Prof. Dr. Roland Scheer, MLU Halle-Wittenberg
Thu, 2015-11-19 14:15
Entanglement entropy in a holographic model of the Kondo effect
Mario Flory
MPI Munich

Starting from a holographic model a magnetic impurity interacting with a strongly coupled system, I focus on the challenges of computing gravitational backreaction in this model, which demands a study of the Israel junction conditions. I present general results on these junction conditions which may be relevant more generally in the AdS/boundary CFT correspondence. Furthermore, similar junction conditions for a bulk Chern-Simons field appearing in the holographic Kondo model are discussed. I then focus on the computation and interpretation of entanglement entropy in the holographic Kondo model. The holographic g-theorem will be discussed as well as a geometric construction that allows to reproduce results obtained by conformal perturbation theory on the boundary.
Wed, 2015-11-18 16:15(HS 2, Abbeanum)
Theoretical spectroscopy: how to calculate electronic excitations of materials from first-principles
Prof. Silvana Botti, FSU Jena
Tue, 2015-11-17 16:15(SR 5, Helmholtzweg 4)
Conformal Field Theory
Prof. Martin Ammon
Fri, 2015-11-13 10:15(SR 2, HHW 5 (gelbes Haus))
Atomic Quantum Simulation of Abelian and non-Abelian Gauge Theories (II)
Prof. Wiese
Thu, 2015-11-12 16:15(SR 5, HHW 4)
Atomic Quantum Simulation of Abelian and non-Abelian Gauge Theories (I)
Prof. Wiese
Tue, 2015-11-10 16:15(SR 5, Helmholtzweg 4)
Conformal Field Theory
Prof. Martin Ammon
Mon, 2015-11-09 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Von seinen eigentlichen künstlerischen Leistungen wissen wir wenig. - Der Architekt Ernst Neufert und das Abbeanum in Jena
Dip.-Ing. Udo Gleim, TU Darmstadt
Thu, 2015-11-05 17:00
Prof. Dr. Anne L'Huillier, Universität Lund (Schweden)

HS 1, Max-Wien-Platz
Tue, 2015-11-03 16:15(SR 5, Helmholtzweg 4)
Conformal Field Theory
Prof. Martin Ammon
Thu, 2015-10-29 14:15
Massless modes and Spontaneous Symmetry Breaking in QFT and Holography
Dr. Amadeo Jimenez Alba
FSU Jena
Wed, 2015-10-28 16:15(HS 2, Abbeanum)
Constructing interacting QFTs via OPEs
Dr. Markus Fröb, Universität Leipzig

Abstract: I will review a new approach to constructing interacting (Euclidean) QFTs in 4 dimensions via the operator product expansion (OPE), and a number of important results that have been proven in the last years using the Polchinski-Kopper flow equation framework, such as existence, convergence and factorisation properties of the OPE in a perturbative sense for non-gauge theories. Lastly, I present on-going work on the generalisation to gauge theories.
Mon, 2015-10-26 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
100 Jahre Forschung zur allgemeinen Relativitätstheorie (Physikalisches Kolloquium anläßlich des 75. Geburtstages von Prof. Dr. Gernot Neugebauer)
Prof. Dr. Hubert Goenner, Universität Göttingen

Zusammenfassung: Nach einer kurzen Einführung in die Allgemeine Relativitätstheorie gibt der Vortrag eine historisch-chronologisch angeordnete Übersicht über die Forschung seit Einsteins Publikation von 1915 und eine Auswahl der beteiligten Personen. Die aus der Theorie folgenden beobachtbaren Effekte, durch die die Theorie eindrucksvoll bestätigt wurde, werden ausführlich besprochen ebenso wie zukünftige geplante Messungen. Die Frage, ob es es "eine goldene Periode" der Gravitationsforschung gegeben hat, wird zum Schluss kommentiert.
Thu, 2015-10-22 14:15(SR 5, Helmholtzweg 4)
Nucleon structure from Lattice QCD at nearly physical quark masses
Dr. Andre Sternbeck
Tue, 2015-10-20 16:15(SR 5, Helmholtzweg 4)
Introduction to Lattice QCD
Dr. Andre Sternbeck
Tue, 2015-09-01 16:15(SR 5, Helmholtzweg 4)
Multicritical Point and Competing Orders of Graphene's Dirac Electrons
Laura Classen, Heidelberg
Tue, 2015-07-21 16:15(SR 5, Helmholtzweg 4)
Invariant classification and limits of superintegrable systems
Dr. Jonathan Kress, University of New South Wales (Sydney)

A classical Hamiltonian system possessing more globally defined conserved quantities than degrees of freedom is said to be superintegrable. Such systems possessing the maximum number of conserved quantities quadratic in the momenta have been much studied because of their connection with separation of variables and special functions. In two dimensions it has been shown that singular limits between `non-degenerate' superintegrable systems mirror limits between othogonal polynomials in the Askey scheme. As a first step in extending this to higher dimensions, all second order superintegrable systems with a `non-degenerate' potential have recently been classified and shown to arise by singular limits from a generic system on the 3-sphere. This classification and the relationships between the systems, which is joint work with Joshua Capel and Sarah Post, will be discussed.
Thu, 2015-07-16 14:15(SR 5, Helmholtzweg 4)
Gauge Theory of the (infinite-dimensional) Translation Group and Gravitation
Dr. Christian Wiesendanger, Zurich
Short Abstract: The seminar will address two interrelated questions:
- What if inertial and gravitational masses would differ off the mass shell? Could this be the basis of a theory of gravitation?
- Can gauge theories of infinite-dimensional gauge groups (example is the 4-dim Translation Group) be mathematically consistently defined so that the classical gauge field Hamiltonian is positive-definite and the quantum theory renormalizable?
Fri, 2015-07-10 16:15(HS 2, Abbeanum)
Finite differencing schemes for GLM-RMHD (Master Thesis Defense)
by Tom Dörffel
A class of finite differencing high-resolution shock-capturing methods for special relativistic magnetohydrodynamics is presented. The divergence condition is controlled by the divergence cleaning approach of Dedner (2002). By performing a series of standard tests the schemes are proven to be high-order accurate for smooth solution and stable in the case of strong shocks.
Tue, 2015-07-07 16:15(SR 5, Helmholtzweg 4)
On the phase structure of imbalanced fermionic systems
Dr. Tina Herbst, ITP Heidelberg
Tue, 2015-06-30 16:15
QCD effective potential with strong magnetic fields
Dr. Sho Osaki (KEK, Japan)
Mon, 2015-06-29 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Die Neudefinition des Kilogramm: Aktueller Stand und mögliche Auswirkungen auf die Darstellung und Weitergabe der Einheit
Dr. Michael Borys, Physikalisch-Technische Bundesanstalt
Tue, 2015-06-23 16:15(SR 5, Helmholtzweg 4)
Exploring some elliptic operators in Gravitation and Physical Oceanography
Dr. Jose Luis Jaramillo, Universität Brest

We discuss two physical problems in which the study of
the spectral properties of certain elliptic operators,
related to the Laplace-Beltrami operator on compact
Riemannian manifolds, appear naturally. The first problem
dwells in a gravitational context, namely the stability of
black hole apparent horizons, and addresses the properties
of a non-selfadjoint elliptic operator defined on closed
codimension-2 surfaces. The second problem deals with the
slow motions in the ocean and brings about the discussion of
the Laplace-Beltrami operator associated with an effective metric
in the oceanic basic, namely a compact manifold with boundaries.
The two problems are technically and conceptually related, in
particular through the spectral approach we adopt for their study.
The main goal in this talk is to present a brainstorm exercise
aiming at identifying the most suited mathematical strategy
for these problems.
Thu, 2015-06-18 14:15(SR 5, Helmholtzweg 4)
How much nonperturbative is the nonperturbative regime of QCD?
Dr. Matthieu Tissier,
LPTMC (Laboratoire de Physique Théorique de la Matière Condensée),
Université Pierre et Marie Curie, Paris.


Studying the high energy regime of QCD is a problem that can be tackled by perturbation theory. This is a consequence of asymptotic freedom, which states that the coupling constant of QCD decreases when increasing the energy. The low energy regime (often called the "nonperturbative regime") is much more difficult to access, mainly because the standard perturbation theory is not applicable anymore.

Nonetheless, I will discuss the possibility of studying the low-energy regime of QCD perturbatively. The main idea is to perform perturbation theory not around the usual Faddeev-Popov action, but around a simple extension of the latter, known as the Curci-Ferrari model. I will discuss the properties of this model and present several 1-loop calculations 1) for correlation functions 2) for the phase diagram of QCD. Comparison with lattice data show that all these quantities can be reproduced with a precision of the order of 15-20%.
Mon, 2015-06-15 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Power and Magnet Applications of High Temperature Superconductors
Prof. Dr. Bernhard Holzapfel, Karlsruher Institut für Technologie
Thu, 2015-06-11 14:15(SR 5, Helmholtzweg 4)
On the Search for Inhomogeneous Phases in Fermionic Models
Dr. Felix Karbstein
Helmholtz-Institut Jena

We revisit the Gross-Neveu model with N fermion flavors in
1+1 dimensions and compute its phase diagram at finite
temperature and chemical potential in the large-N limit.
To this end, we double the number of fermion degrees of
freedom in a specific way which allows us to detect
inhomogeneous phases in an efficient manner. We show
analytically that this "fermion doubling trick" predicts
correctly the position of the boundary between the
chirally symmetric phase and the phase with broken chiral
symmetry. Most importantly, we find that the emergence of
an inhomogeneous ground state is predicted correctly. We
critically analyze our approach based on this trick and
discuss its applicability to other theories, such as
fermionic models in higher dimensions, where it may be
used to guide the search for inhomogeneous phases.
Thu, 2015-06-04 14:15(SR 5, Helmholtzweg 4)
Glueballs in the Dyson-Schwinger approach
Dr. Helios Sanchis Alepuz, Justus-Liebig Universität, Gießen
Tue, 2015-06-02 16:15(SR 5, Helmholtzweg 4)
The Topology of Chiral Vector Bundles (topological insulators of type AIII)
Dr. Giuseppe de Nittis, Friedrich-Alexander-Universität Erlangen-Nürnberg

The classification of topological states of matter is an important hot topic in mathematical physics. In this talk I will describe a new approach to the classification of topological quantum systems in class AIII which is based on the study of a new category of vector bundles. The objects of this category, the chiral vector bundles, are pairs constituted by a complex vector bundle along with one of its automorphisms. We provide a classification for the homotopy equivalence classes of these objects which is based on the construction of a suitable classifying space. The computation of the cohomology of the latter allows us to introduce a proper set of characteristic cohomology classes: Some of those just reproduce the ordinary Chern classes but there are also new odd-dimensional classes which take care of the extra topological information introduced by the chiral structure. Chiral vector bundles provide the proper geometric model for topological quantum systems in class AIII, namely for systems endowed with a (pseudo-)symmetry of chiral type. The classification of the chiral vector bundles over sphere and tori (explicitly computable up to dimension 4) recover the commonly accepted classification for topological insulators of class AIII which is usually based on the K-group K1. However, this new classification turns out to be even richer since it takes care also for the possibility of non trivial Chern classes.
Mon, 2015-06-01 17:15(Hörsaal 1 Abbeanum, Fröbelstieg 1 (PAF Kolloquium))
Keine Panik! Die Physik der Fußgängerdynamik und Evakuierungsprozesse
Prof. Dr. Andreas Schadschneider, Universität Köln
Tue, 2015-05-26 16:15(SR 5, Helmholtzweg 4)
Entanglement entropy as a probe for quantum gravity
Dr. Michael Ferlaino
University of Swansea, UK
Thu, 2015-05-21 14:15(SR 5, Helmholtzweg 4)
Induced QCD with Nc-1 auxiliary bosonic fields
Dr. Bastian Brandt, Universität Regensburg
Wed, 2015-05-20 16:15(SR 5, Helmholtzweg 4)
Binary Neutron Stars with Spin
Prof. Wolfgang Tichy, Florida Atlantic University

Note: Changed time from usual slot on Tuesday to Wednesday
Tue, 2015-05-19 16:15(SR 5, Helmholtzweg 4)
Modeling Liquids and Bulk Metallic Glasses
Prof. Jean Bellissard, Georgia Institute of Technology Atlanta, USA
Mon, 2015-05-18 16:15(HS 2, Abbeanum)
New efficient algorithm for the isometric embedding of 2-surface metrics in 3 dimensional Euclidean space
Wolfgang Tichy, Florida Atlantic University

We present a new numerical method for the isometric embedding of 2-geometries specified by their 2-metrics in three dimensional Euclidean space. Our approach is to directly solve the fundamental embedding equation supplemented by six conditions that fix translations
and rotations of the embedded surface. This set of equations is discretized by means of a pseudospectral collocation point method. The resulting nonlinear system of equations are then solved by a Newton-Raphson scheme. We explain our numerical algorithm in detail. By studying several examples we show that our method converges provided we start the Newton-Raphson scheme from a suitable initial guess. Our novel method is very efficient for smooth 2-metrics.
Wed, 2015-05-13 16:00(HS 2, Abbeanum)
Spinning particle in a Kerr background
Dr. Georgios Lukes-Gerakopoulos, Institute of Theoretical Physics, Charles University in Prague, Czech Republic
Tue, 2015-04-28 16:15
Modeling the Electronic Properties of Graphene
Prof. Lorenz von Smekal - Technische Universität Darmstadt
Fri, 2015-03-06 16:15(HS 2, Abbeanum)
Das Spätzeitverhalten relativistischer Wellen (Masterverteidigung)
Martin Becker, FSU Jena
Wed, 2015-01-28 17:15(Seminarraum HI Jena, Fröbelstieg 3)
Lightlike inhomogenities in worldline pair creation
Dr. Anton Ilderton, Chalmers University Göteborg

The locally constant field approximation (LFCA) is commonly used to calculate the nonperturbative pair production probability in electromagnetic fields.
In certain classes of fields, for example longitudinal electric fields depending on lightfront time, the LCFA is known to be exact. Using the worldline description of the effective action, we show that the reason for this is closely tied to the zero-mode problem of lightfront quantisation, and the so-called “triviality” of the lightfront vacuum.
Tue, 2015-01-27 16:15(SR 5, Helmholtzweg 4)
The Callias Index Theorem Revisited
Dr. Marcus Waurick, Technische Universität Dresden
Wed, 2015-01-21 16:15(HS 2, Abbeanum)
New Frontiers in integrated photonics: supersymmetry and unphysical phenomena
Prof. Dr. Alexander Szameit, IAP Universität Jena
Tue, 2015-01-20 16:15(SR 5, Helmholtzweg 4)
Asymptotic Safety in Gravity
Dr. Astrid Eichhorn, Imperial College London
Wed, 2015-01-14 16:00(SR 309, Carl-Zeiß-Str. 3)
From Schwarzschild to General Relativity: modeling physical phenomena with the help of geometry
Dr. Carla Cederbaum, Universität Tübingen
Tue, 2015-01-13 16:15
Spectral theory for continuum one-dimensional quasicrystal models
Dr. Christian Seifert, Technische Universität Hamburg-Harburg

We consider an ergodic family $(H_\omega)_{\omega\in\Omega}$ of continuum one-dimensional Schr\"odinger operators, where we allow for measures as potentials. We show that the random operator $H$ has Cantor type spectra of Lebesuge measure zero under suitable finite local complexity conditions on the potentials. Such operator families appear in the study of quasicrystalline models.
Thu, 2015-01-08 14:15(SR 5, HH 4, instead of the quantum theory seminar)
Perturbative Quantum Gravity III
Prof. Ilya Shapiro
Universidade Federal de Juiz de Fora
Wed, 2015-01-07 16:15(HS 2, Abbe., instead of the seminar of the institute)
Perturbative Quantum Gravity II
Prof. Ilya Shapiro
Universidade Federal de Juiz de Fora
Tue, 2015-01-06 16:15(SR 5, Helmholtzweg 4)
Perturbative Quantum Gravity I
Prof. Ilya Shapiro
Universidade Federal de Juiz de Fora
Thu, 2014-12-18 14:15
Critical behavior in spherical and hyperbolic space
Dr. Dario Benedetti (AEI Potsdam)
Wed, 2014-12-17 16:15
A Simple Proof of the Kochen-Specker Theorem on the Problem of Hidden Variables
Prof. Norbert Straumann, Universität Zürich
Tue, 2014-12-16 16:15(SR 5, Helmholtzweg 4)
Rendering integrands positive - subset method for lattice QCD at high density
Dr. Falk Bruckmann
Universität Regensburg
Wed, 2014-12-10 16:00(HS 2, Abbeanum)
apl.: AG Fachdidaktik der Physik und Astronomie
Prof. Lotze
Tue, 2014-12-09 16:15(SR 5, Helmholtzweg 4)
(Non)-Fermi Liquids
Dr. Tilman Enss
Ruprecht-Karls-Universität Heidelberg
Fri, 2014-12-05 11:30(Rosensäle)
Binary neutron stars: what we understand and what we don't
From Luciano Rezzolla for the GWA14 conference

I will review the recent progress made in modelling binaries of compact stars and the role played by magnetic fields and the equation of state in their evolution. Special attention will be paid to highlighting how the progress of ab-initio fully relativitistic calculations can be used to explain several aspects of the phenomenology of short gamma-ray burst, but also how new observations on the X-ray afterglows represent new riddles for the theoretical modeling.
Fri, 2014-12-05 10:00(Rosensäle)
Constraining the nature of gravitational waves with binary pulsar experiments
From Paulo Freire for the GWA14 conference

In this talk I present some recent pulsar timing experiments for double neutron stars that test general relativity's quadrupolar gravitational wave emission formula with unprecedented precision. I then present the results of timing of millisecond pulsar - white dwarf systems that severely constrain the emission of dipolar gravitational waves (DGW) for a wide range of neutron star masses. Apart from constraining (and in some cases excluding) alternative theories of gravity that predict DGW emission, these results reinforce our confidence in the templates being used to search for the GW signal of NS-NS and NS-BH inspiral events in the advanced LIGO and Virgo detectors.
Fri, 2014-12-05 09:00(Rosensäle)
Highest order post-Newtonian dynamics of non-spinning and spinning compact binaries in general relativity
From Gerhard Schäfer for the GWA14 conference

The talk delivers insight into the calculations of highest order post-Newtonian (PN) Hamiltonians for binary black holes. The conservative dynamics is presented up to 4 PN order for binaries with both non-spinning and spinning components, where the spins are counted of 0.5 PN order. The related dissipative radiation reaction dynamics is known up to 4.5 PN order. As application, the Innermost Stable Circular Orbit for spinless binaries is given through 4 PN order and the test-body limit is compared with the exactly known ISCO of a test-body orbiting a Schwarzschild black hole.
Thu, 2014-12-04 10:00(Rosensäle)
Binary black holes: Waveform modeling and two-body dynamics
From Harald Pfeiffer for the GWA14 conference

This talk will introduce the Spectral Einstein Code, a general relativistic code to solve the inspiral and merger of two black holes. I will give an update on numerical results with SpEC, and will discuss several applications of the simulations, among them the construction of waveform models within the effective-one-body formalism, the study of gravitational self-force effects through comparable-mass binary black hole simulations, and a comparison of the post-Newtonian precession dynamics with numerical simulations.
Thu, 2014-12-04 09:00(Rosensäle)
Gravitational waves from coalescing neutron star binaries
From Masaru Shibata for the GWA14 conference

Wed, 2014-12-03 10:00(Rosensäle)
Post-merger Oscillations in Binary Neutron Star Mergers
from Nikolaos Stergioulas for the GWA14 conference

Because of the recent discovery of two-solar-mass neutron stars, the equation of state of high density matter is likely to be sufficiently stiff to allow for a long-lived remnant, when two neutron stars merge. The merger excites a number of oscillation modes, having large (nonlinear) amplitude, that are interesting as gravitational waves sources for second- and third-generation interferometric detectors. Apart from a dominant linear oscillation mode, additional nonlinear contributions appear. I discuss the main properties of these oscillations as well as the prospects of constraining the mass and radius (and thus the equation of state) with future detections.
Wed, 2014-12-03 09:00(Rosensäle)
Searching for gravitational waves from the early Universe
from Fabian Schmidt for the GWA14 conference

Tue, 2014-12-02 11:30(Rosensäle)
Gravitational wave detection using squeezed light
from Roman Schnabel for the GWA14 Conference

Current gravitational wave (GW) detectors are Michelson-type kilometre-scale laser interferometers measuring the distance changes between in vacuum suspended mirrors. The sensitivity of these detectors is limited by quantum noise of the laser light. Since 2010, GEO600 has been using so-called nonclassical light that has a ‘squeezed’ quantum noise, and it has been demonstrated that squeezed light is able to increase the GW detector sensitivity at shot-noise limited frequencies. In future, squeezed light might be used to further improve the sensitivity of GW detectors, then also at radiation pressure noise dominated frequencies and at frequencies where photon-phonon scattering is limiting the detectors performance.
Tue, 2014-12-02 10:00
Gravitational waves from black-hole binaries
from Mark Hannam for the GWA14 Conference
Tue, 2014-12-02 09:00
Progress in Three-dimensional Supernova Modeling
from Hans-Thomas Janka for the GWA14 conference

3D supernova simulations have become possible only very recently and have already led to the discovery of novel and unexpected phenomena, although they still need to confirm the basic theoretical concepts of the explosion mechanism. The talk will review the status of 3D modeling and interesting new perspectives to probe the supernova core dynamics by neutrinos and gravitational waves measured in the case of a next galactic event.
Mon, 2014-12-01 19:00(Max-Wien-Platz 1, Lecture Hall 1)
Gravitationswellenastronomie: Bald Neues von der dunklen Seite des Universums!
Public Talk of the GWA14 Conference from Karsten Danzmann

Können wir das Universum hören? Auf den ersten Blick ist das eine unsinnige Frage, denn natürlich gibt es im Weltall keine Luft, in der sich der Schall ausbreiten könnte. Wenn aber un­sere Ohren nur empfindlich genug wären, dann könn­ten sie auf eine besondere Art von Wellen reagieren: auf Gravitationswellen! Vor mehr als 90 Jahren sagte Al­bert Einstein die Existenz von Gravitationswellen als Konsequenz seiner allgemeinen Relativitätstheorie vor­aus. Gravitationswellen sind winzige Verbiegungen des Raumes und der Zeit, die von schnellbewegten, großen Massen erzeugt werden und sich mit Lichtgeschwindig­keit wellenförmig ausbreiten. Sie wurden noch nie di­rekt nachgewiesen. Mehrere laserinterferometrische Gravitationswellendetektoren mit Armlängen von Ki­lometern werden gegenwärtig auf der Erde betrieben, um Gravitationswel­len zu erforschen, darunter auch GEO600 in der Nähe von Hannover. Bald folgen Detektoren im Weltraum mit Millionen km Armlänge, insbesondere die Satelliten-Mission LISA. Ausgangspunkt für diese geheimnis­vollen Wellen könnten z. B. verschmelzende Doppel­sterne, Neutronensterne, Supernovae, Schwarze Löcher und der Urknall sein. Ihre Beobachtung erfordert modernste Lasertechnologie und Messungen an der quantenmechanischen Nachweisgrenze.
Mon, 2014-12-01 15:00(Rosensäle)
Beyond the second generation of gravitational wave detectors
from Ronny Nawrodt for the GWA14 Conference

Gravitational wave detectors are currently upgraded to the 2nd generation achieving extremely high sensitivities in a wide frequency band. A first direct detection of gravitational waves is expected once these instruments are getting online. Such a detection will mark the starting point for a gravitational wave based astronomy. Thus, detectors of the third generation are designed to be used as efficient astronomical observatories. For this purpose the sensitivity of the 2nd generation detectors has to be enhanced. As the sensitivity of current instruments approaches the thermal noise floor of their fused silica components a radical change of materials is necessary. Additionally, 3rd generation detectors will be operated at cryogenic temperatures to further reduce thermal noise and increase their sensitivity. This talk will give an overview of proposed technologies towards 3rd generation detectors leading to a 10 times higher sensitivity throughout the audio band. The focus will lie on the selection of materials for the optics as well as the suspension elements according to their properties. The characterisation of these materials and the choice of their operational temperature is discussed as well.
Mon, 2014-12-01 14:00
From the beginning to the second generation of gravitational wave detectors
from David Shoemaker for the GWA 2014 Conference

A brief history of gravitational wave detection using laser interferometers will be given, followed by a status report on one example of the second generation of detectors, Advanced LIGO.
Tue, 2014-11-25 16:00(SR 5, Helmholtzweg 4)
Dark energy and the uniqueness of general relativity
Prof. Matthias Bartelmann
Ruprecht-Karls-Universität Heidelberg
Thu, 2014-11-20 14:15
Hamiltonian approach to QCD in Coulomb gauge: From the vacuum to finite temperatures
Prof. Dr. Hugo Reinhardt, Universität Tübingen
Wed, 2014-11-19 16:15(HS 2, Abbeanum)
Lightfront quantisation and strong field QED
Greger Torgrimsson (Chalmers)
Fri, 2014-11-14 16:00(HS 2, Abbeanum)
Ab Initio Simulationen zur Struktur und Dynamik warmer dichter Aluminiumplasmen
Hannes Rüter, MSc,
Universität Rostock
Thu, 2014-11-13 14:15
Non-Equilibrium Dynamics of a Holographic Superfluid
Andreas Samberg,
Ruprecht-Karls-Universität Heidelberg
Thu, 2014-11-06 14:15
Can effects of quantum gravity be observed in the CMB?
Prof. Claus Kiefer, University Cologne
Tue, 2014-11-04 16:15(SR 5, Helmholtzweg 4)
Supersymmetric Yang Mills Theories
Dr. Georg Bergner, Universität Bern
Tue, 2014-10-28 16:15(SR 5, Helmholtzweg 4)
Coupling constant metamorphosis and conformally covariant Laplacians
Dr. Jonathan Kress (University of New South Wales, Sydney)