CPT

Calendar of Physics Talks Vienna

Non-relativistic expansion of general relativity
Speaker:Jelle Hartong (University of Edinburgh)
Abstract:Joint TU/UV Theory Seminar: I will discuss recent progress in the 1/c expansion of general relativity where c is the speed of light. This is an off shell and covariant approximation of general relativity that is similar to the post-Newtonian approximation. I will show that it provides an action principle for matter coupled Newton-Cartan gravity which on shell is described by torsionless Newton-Cartan geometry. For certain choices of matter, instead of leading to Newton-Cartan gravity, it rather gives rise to matter coupled Galilean gravity and I will discuss these cases as well. Finally, time permitting, I will end with some comments about the 1/c expansions of the Nambu-Goto and Polyakov actions for strings.
Date: Tue, 10.12.2019
Time: 13:45
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:S. Fredenhagen, D. Grumiller

The perturbative gradient flow
Speaker:Robert Harlander (RWTH Aachen University)
Abstract:im Rahmen des Teilchenphysikseminars: The so-called Yang-Mills gradient flow has become a successful concept in lattice calculations during the last few years. Besides its technical virtues in the non-perturbative regime, it was shown to be accessible in perturbation theory as well. In this talk, I present a number of promising applications, among them a potential extraction of $\alpha_s(M_Z)$ from first-principle calculations, and a novel lattice definition of the energy-momentum tensor.
Date: Tue, 10.12.2019
Time: 16:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, S. Plätzer

Hadronic effects and effective field theories at the precision frontier
Speaker:Peter Stoffer (University of California, San Diego)
Abstract:Traditionally,low-energy precision experiments have taken a complementary role to direct searches for physics beyond the Standard Model(SM)at high-energy colliders.The absence of direct signals of new physics at the LHC makes it plausible that particles beyond the SM are much heavier than the electroweak scale. Therefore, collider experiments also play the role of precision indirect searches.Effective field theories(EFTs)provide a model-independent unified framework for describing and constraining new physics in experiments from LHC energies down to the hadronic scale.The increasing precision at the experimental frontier calls for a better control of theory uncertainties, which at low energies are usually dominated by non-perturbative hadronic effects. Theoretical progress is required both in the description of hadronic SM contributions, as well as in the EFT description of new physics.
Date: Wed, 11.12.2019
Time: 16:15
Duration: 60 min
Location:Fakultät für Physik, Kleiner Seminarraum, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, S. Plätzer, M. Procura

Stability of the positive mass theorem for axisymmetric manifolds
Speaker:Edward Bryden (Tübingen)
Abstract:Im Rahmen des Literaturseminars: We investigate the stability of the Positive Mass Theorem for three-dimensional axisym- metric manifolds. It is widely known that asymptotically at manifolds with nonnegative scalar curvature have nonnegative ADM mass, and that the only asymptotically at manifold with nonnegative scalar curvature and zero ADM mass is Euclidean space. We will show that axisymmetric manifolds with nonnegative scalar curvature and small ADM mass, and which satisfy an additional technical assumption, are close to Euclidean space in a Sobolev sense.
Date: Thu, 12.12.2019
Time: 14:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien
Contact:P.T. Chrusciel, D. Fajman

2D Materials are like people – it is the defects that make them interesting
Speaker:Sarah Haigh, University of Manchester
Abstract:The talk takes place in the frame of the first VDSP Science Day. Please register: https://vds-physics.univie.ac.at/activities/science-day/
Date: Thu, 12.12.2019
Time: 16:20
Duration: 60 min
Location:Sky Lounge, OMP
Contact:VDS Physics

Differential equations and iterated integrals for massive multi-loop Feynman integrals
Speaker:Stefano Di Vita (INFN Mailand)
Abstract:In this talk I will give an overview of the differential equations method for the calculation of multi-loop Feynman integrals, which was recently applied to several cases where massive legs and propagators are present. I will discuss how the systems of differential equations arise, how they are brought in canonical form with the help of the Magnus exponential, what functions can be used to give a closed-form representation of the solution, and how they are analytically continued to the kinematic regions of interest. Some examples will be given, such as the master integrals for the NNLO QED corrections to mu-e scattering, which are crucial for the physics program of MUonE, an experiment proposed with the goal of determining the leading hadronic contribution to the muon g-2 in a novel way.
Date: Fri, 13.12.2019
Time: 16:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, S. Plätzer, M. Procura