|
Calendar of Physics Talks Vienna
| The Three Laws of Future Light Cone Thermodynamics |
| Speaker: | Maulik Parikh (Arizona State University, Tempe, Arizona) |
| Abstract: | im Rahmen des Seminars für Mathematische Physik (Joint TU/UV Theory Seminar): We show that there exist *local* gravitational laws — valid near any point in any space-time — which take the form of the laws of thermodynamics. To derive these laws, we will define a surface called the stretched future light cone. Then the gravitational entropy is precisely one quarter of the area of this surface. Interestingly, we find that, like the ordinary first law of thermodynamics but unlike its black hole counterpart, our local gravitational first law also contains a work term. The existence of local gravitational laws provides evidence that gravitational entropy is a property of all space-times, and not just space-times containing event horizons. |
| Date: | Tue, 23.10.2018 |
| Time: | 13:45 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | S. Fredenhagen, D. Grumiller |
| Ion beam spectroscopy of 2D materials |
| Speaker: | Janine Schwestka (TU Wien, Institut für Angewandte Physik) |
| Abstract: | Materials with a thickness of only one atomic layer attracted the attention of theoretical as well as
experimental scientist since their first discovery. Due to their unique electronic and optical properties and
their high flexibility, 2D materials rapidly made their way as promising candidates into various fields of
applications. As a result, more and more monolayer materials are appearing, whereas still their properties
have to be investigated in more detail. With an ion beam spectrometer, charge and energy transfer
between highly charged ions and monolayer materials with different properties are measured. Therefore,
the response of semi-metal graphene as well as semiconducting molybdenum disulfide to a strong and
localized electric field can be probed. |
| Date: | Tue, 23.10.2018 |
| Time: | 16:00 |
| Location: | TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner Hauptstraße 8-10 Yellow Tower „B“, 5th floor, SEM.R. DB gelb 05 B |
| Contact: | Univ.Prof. Dr. Friedrich Aumayr |
| Sputtering of Mercury and Moon Analogue Material by Solar Wind Ions |
| Speaker: | Paul S. Szabo (TU Wien, Institut für Angewandte Physik) |
| Abstract: | The formation of thin exospheres around planets or moons is a very important topic in planetary sciences.
Sputtering by solar wind ions plays an essential role for the emission of particles from the surface. To get a
better understanding of this process, sputtering experiments with the Quartz Crystal Microbalance (QCM)
technique were performed using the mineral Wollastonite (CaSiO3) as an analogue target for the surface of
Moon or Mercury. Kinetic sputtering effects were investigated under different angles of incidence and
agreed very well with predictions from simulation codes. Potential sputtering by ions with higher charge
states was found to significantly increase the sputtering yield, showing the importance of heavy, multiply
charged ions in the solar wind. |
| Date: | Tue, 23.10.2018 |
| Time: | 16:00 |
| Location: | TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner Hauptstraße 8-10 Yellow Tower „B“, 5th floor, SEM.R. DB gelb 05 B |
| Contact: | Univ.Prof. Dr. Friedrich Aumayr |
| Top mass effects in gluon fusion processes |
| Speaker: | Thomas Rauh (IPPP, Durnham) |
| Abstract: | Im Rahmen des Teilchenphysikseminars: Gluon fusion processes are of central importance at the LHC, but suffer
from slow convergence of QCD corrections which are difficult to compute
because the processes are loop induced. They are therefore commonly
treated in the large-mt expansion (LME) which breaks down above the
top threshold. I show how LME-based predictions can be improved
significantly by contructing Pade approximations which also utilize input
from the top threshold $\hat{s}\approx4m_t^2$. The proof of principle is
provided by comparison with recent numerical NLO results for Higgs pair
production and the method can be applied to other processes and at NNLO.
|
| Date: | Tue, 23.10.2018 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, H. Neufeld, S. Plätzer, M. Procura |
| Examples of Compact Einstein four-manifolds with negative curvature |
| Speaker: | Bruno Premoselli (UL Brussels) |
| Abstract: | im Rahmen des joint geometry-relativity seminar: We construct Einstein metrics of negative sectional curvature on ramified covers
of compact hyperbolic four-manifolds with symmetries, initially considered by
Gromov and Thurston. These metrics are obtained through a deformation procedure.
The approximate Einstein metric is an interpolation between a black-hole Einstein
metric near the branch locus and the pulled-back hyperbolic metric. The deformation
relies on an involved bootstrap procedure. Our construction yields the first example
of compact Einstein manifolds with negative sectional curvature which are not locally homogeneous. This is a joint work with J. Fine (ULB).
|
| Date: | Thu, 25.10.2018 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien |
| Contact: | P.T. Chrusciel. M. Eichmair |
|