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Calendar of Physics Talks Vienna
| Chiral power counting of one- and two-body currents, isospin violation, and the pion-nucleon sigma-term |
| Speaker: | Martin Hoferichter (TU Darmstadt) |
| Abstract: | im Rahmen des Teilchenphysikseminar: Nuclear matrix elements are crucial ingredients for the consistent interpretation of direct-
detection experiments searching for dark matter. In the talk I will discuss how chiral power counting provides a scheme to organize the
calculation of these matrix elements, both concerning the relative
scaling of different one-body operators and the suppression of
operators where the (putative) dark-matter particle interacts
with multiple nucleons. Moreover, I will show how the combination of
recent precision measurements in pionic atoms and general constraints
from analyticity, unitarity, and crossing symmetry imposed in the form
of Roy-Steiner equations leads to a very ccurate determination of the
pion-nucleon sigma-term, which measures the scalar matrix ements of
up-and down-quarks.
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| Date: | Tue, 14.04.2015 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, H. Neufeld |
| Introduction to tractor calculus and BGG complexes |
| Speaker: | Callum Sleigh (Universität Wien) |
| Abstract: | im Rahmen des Seminars in Geometric Analysis and Physics (GAP Seminar):
Using the example of projective differential geometry, I will give an
introduction to a collection of geometric tools known as "the tractor
calculus" (following the etymology of 'vector', 'tensor','spinor',
'twistor' etc.) I will show how to use this calculus to construct
complexes of invariant differential operators and discuss applications.
No knowledge beyond elementary Riemannian geometry will be required. |
| Date: | Thu, 16.04.2015 |
| Time: | 11:00 |
| Duration: | 60 min |
| Location: | Fakultät für Mathematik, Oskar-Morgenstern-Platz 1,1090 Wien, 2. Stock, Besprechungszimmer |
| Contact: | M. Bauer (Fak. Math, U.V.), V. Branding (Fak. Math, T.U.), D. Fajman (Fak. Phys, U.V.), J. Joudioux (Fak. Phys, U.V.) |
| Introduction to a Local Thermal Interpretation of the Unruh Effect |
| Speaker: | Albert Georg Passegger (Vienna) |
| Abstract: | im Rahmen des Literaturseminars: Based on the algebraic setting of the Unruh effect discussed in the previous talk ("Algebraic Foundations of the Unruh Effect"), I present recent results by D. Buchholz and C.
Solveen on a new interpretation of the thermal aspects of the Unruh
effect for scalar free fields. If the notion of temperature is defined
using so-called local thermal observables, the local temperature of the
Minkowski vacuum is zero also for the accelerated observer. Finally, I
mention some open physical questions in this approach. |
| Date: | Thu, 16.04.2015 |
| Time: | 14:00 |
| Location: | Arbeitsgruppe Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock, 1090 Wien |
| Contact: | P.T. Chrusciel |
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