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Calendar of Physics Talks Vienna
| Infinite derivative gravity in 2+1 spacetime dimensions |
| Speaker: | Georg Stettinger (Univ. of Groningen, NL) |
| Abstract: | I we will consider the most general quadratic curvature action of massless gravity in 3 space time dimensions which is parity invariant, torsion free and contains the same off-shell degrees of freedom as the Einstein-Hilbert action in general relativity. In the ultraviolet, with an appropriate choice of the propagator given by the exponential of an entire function, the point-like curvature singularity can be smoothened by a Gaussian distribution, while in the infrared the theory reduces to that of the predictions of general relativity. I will also show how to embed new massive gravity in ghost free infinite derivative gravity in Minkowski background as one of the infrared limits. Finally, I will provide the perturbative unitarity conditions for infinite derivative gravity in presence of a cosmological constant in deSitter and Anti-deSitter space times in 3 spacetime dimensions. |
| Date: | Tue, 08.01.2019 |
| Time: | 13:45 |
| Duration: | 60 min |
| Location: | TU Wien, Getreidemarkt 9, Maschinenbaugebäude, 1. Stock, HS Kleiner Schiffbau |
| Contact: | S. Fredenhagen, D. Grumiller, J. Knapp |
| Renormalons, R-evoultion and Renormalon Sum Rule |
| Speaker: | Christoph Regner (Univ. Wien) |
| Abstract: | Perturbation series in QCD are generally known to be divergent and can at best be considered asymptotic.The asymptotic behaviour is caused by contributions from small and large loop momenta in perturbative calculations and manifests itself in poles of the corresponding Borel transform.These poles are usually referred to as renormalons and lead to ambiguities in the definition of perturbative series.In this talk we discuss the implications of these ambiguities and investigate how well renormalon ambiguities can be quantified.Furthermore it will be shown how the introduction of a new scale R can be used to improve the poor convergence behaviour of perturbative series suffering from renormalon ambiguities. From the solution of renormalization group equations with respect to the scale R (R-evolution),one can deduce an analytic all-order expression for the Borel transform of perturbative .... |
| Date: | Tue, 08.01.2019 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, S. Plätzer, M. Procura |
| De Donder-Weyl Hamiltonian theory and precanonical quantization: an untrodden path to quantization of fields and gravity |
| Speaker: | Igor Kanatchikov (Univ. of St. Andrews, UK) |
| Abstract: | I will discuss(I)the De Donder-Weyl (DW) Hamiltonian and Hamilton-Jacobi formulation of classical fields and the underlying mathematical structures which can be used for quantization (the polysymplectic structure and the Poisson-Gerstenhaber brackets),(II)a field quantization based on those structures (precanonical quantization) which leads to a hypercomplex rather than infinite-dimensional generalization of quantum theory as a description of quantum fields,(III)examples of precanonical quantization of a nonlinear scalar field on flat and curved background, and the pure Yang-Mills field, (IV) the consistency of precanonical quantization with the Ehrenfest theorem,(V)the relation to the standard QFT in the functional Schrödinger representation, which appears as a singular limiting case,(VI)precanonical quantization of general relativity in vielbein Palatini formulation and the ..... |
| Date: | Thu, 10.01.2019 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien |
| Contact: | P.T. Chrusciel, D. Fajman |
| Open quantum dynamics induced by light scalar fields |
| Speaker: | Christian Käding (U. Nottingham & TU Wien) |
| Abstract: | Light scalar fields have been interesting subjects for modifications of the standard model or general relativity in recent years. For example, a commonly employed alteration of Einstein‘s theory of gravity
is achieved by conformally coupling a scalar field to the metric tensor. Light conformally coupling scalar fields are expected to cause a gravity-like fifth force of Nature and some have successfully been
constrained in quantum experiments like atom interferometry. In this context it is important to understand open quantum dynamical effects like decoherence which can be induced by the presence of scalar
fluctuations. I will illustrate how a robust and practicable formalism based on the influence functional can be used to derive a single particle momentum subspace
master equation which describes the open quantum dynamics induced by conformally coupled scalar fields. |
| Date: | Thu, 10.01.2019 |
| Time: | 16:00 |
| Location: | Institute for Theoretical Physics, TU Wien, Seminar room 10th floor (yellow area), Wiedner Haupstr. 8-10, 1040 |
| Contact: | Anton Rebhan |
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