CPT

Calendar of Physics Talks Vienna

Quantum Time
Speaker:Lorenzo Maccone (CoQuS)
Abstract:I give a fully quantum treatment of time in quantum mechanics. It requires an extensionof textbook quantum mechanics. Some philosophical and foundational considerations on the meanings of time will be given
Date: Mon, 20.01.2020
Time: 16:30
Duration: 120 min
Location:Universität Wien, Lise Meitner- Hörsaal, Strudelhofgasse 4, 1090 Wien
Contact:Susanne Ninaus-Meznik

Beyond General Relativity: causality issues and geometric inflation
Speaker:Jose Edelstein (Santiago de Compostela U.)
Abstract:We will explore the consequences of imposing consistency conditions in the introduction of higher curvature corrections to the Einstein-Hilbert Lagrangian. We will discuss two separate issues. First, we will argue that causality and unitarity put some tough restrictions at tree level, pointing in the direction of a UV stringy completion. Second, we will show that it is possible to write down an action given by an infinite series in the Riemann tensor with nice properties in terms of its spectrum and cosmology, which suggests a tantalizing mechanism of geometric inflation.
Date: Tue, 21.01.2020
Time: 13:45
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:S. Fredenhagen, D. Grumiller

The virtual photon model for interatomic Coulombic decay: solvents, surfaces and the far-field
Speaker:Robert Bennett (University of Freiburg, Institut of Physics, Freiburg/Germany)
Abstract:Multi-centre decay processes such as interatomic Coulombic decay (ICD) or resonant energy transfer (RET) are usually described through ab initio electron dynamics. While such methods are very powerful, they are based on instantaneous electron-electron interactions and therefore do not take into account the phase evolution of signals from one place to another. This is usually a good assumption due to the small distances involved, but becomes less reasonable as distances are increased. Methods based on dipole-dipole coupling in quantum electrodynamics can fully describe the smooth transition from near- to far-field behaviour, as well as take into account the dielectric response of a background medium which can be inhomogeneous. In this talk I will outline how the virtual photon model works, and discuss the limits of its applicability. Finally I will give some examples of its use in past an
Date: Tue, 21.01.2020
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

Supercritical wave maps
Speaker:Roland Donninger (Universität Wien)
Abstract:I will introduce the wave maps equation, a nonlinear geometric generalization of the wave equation. In the physics literature wave maps are known as sigma models and they play an important role in various fields like particle physics, solid state physics, and general relativity. The mathematical study of wave maps received considerable interest in the last 20 years. I will discuss some fundamental problems connected to supercriticality and outline recent progress in the understanding of singularity formation.
Date: Wed, 22.01.2020
Time: 14:15
Location:Seminar room FH gelb 10, Institute for Theoretical Physics – Vienna University of Technology, Wiedner Hauptstraße 8 – 10, 10th floor, B (yellow tower)
Contact:Stefan Rotter

Topics in massive and partially massless gravity
Speaker:Cedric Deffayet (CNRS Paris, IAP and IHES)
Abstract:The wish to "give a mass to the graviton" (or to make gravity finite range) is old and has motivations ranging from cosmology to the achievement of a theoretical challenge. After reviewing the attempts in this direction and their numerous obstacles, I will discuss recent progresses. In a second part of the talk, I will introduce some our results on the construction of a consistent partially massless graviton on curved backgrounds as well as that of a theory of multiple partially massless such fields.
Date: Thu, 23.01.2020
Time: 14:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien
Contact:P.T. Chrusciel, D. Fajman

An optical dipole trap in microgravity
Speaker:Christian Vogt (ZARM, Universität Bremen )
Abstract:Cold atom based sensors have proven to be effective tools with wide applications in measuring weakest forces and thereby in testing fundamental physics e.g. the weak equivalence principle. As the sensitivity of atom interferometer measurements scales with the square of interrogation time, great effort has been made to bring these techniques to microgravity (µg) environments. The talk will be about the ongoing cold atom activities in the drop tower in Bremen with a focus on the implementation of an optical dipole trap. Furthermore, the key techniques to produce atomic clouds of rubidium as cold as 34 pK on an atom chip will be presented.
Date: Fri, 24.01.2020
Time: 15:30
Location:Atominstitut, Hörsaal, Stadionallee 2, Wien 2
Contact:P. Haslinger