Calendar of Physics Talks Vienna

Higher-spin theories from a Hamiltonian viewpoint
Speaker:Andrea Campoleoni (ULB Brussels)
Abstract:im Rahmen des Seminars für Mathematische Physik: After an introduction to Fronsdal’s description of the dynamics of free particles of spin greater than two, we show how one can recast the action principle in Hamiltonian form. Following an approach developed by Regge and Teitelboim for general relativity, the latter step is then used to identify “higher-spin” conserved charges which generalise total energy and angular momentum. To this end, we specialise the discussion to fields propagating on an Anti de Sitter background and we discuss how the previous results fit within the conjectured AdS/CFT correspondences involving higher spins. We conclude with an overview of the potential applications of a closed-form expression for higher-spin charges.
Date: Tue, 18.10.2016
Time: 14:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:S. Fredenhagen, H. Steinacker

Self-organized TiO2 nanotube arrays: Formation, features and applications
Speaker:Prof. Dr. Patrik Schmucki (University of Erlangen-Nuremberg, Department of Materials Science, LKO, Erlangen/Germany)
Abstract:TiO2 nanomaterials have over the last 30 years attracted tremendous scientific and technological interest. Main research direction using TiO2 in functional applications are the use in photocatalysis e.g. for the direct splitting of water into H2 and O2 to generate the potential fuel of the future, hydrogen; the use in Grätzel type solar cells and in biomedical applications. Over the past decades various 1D and highly defined TiO2 morphologies were explored for the replacement of nanoparticle networks and were found in many cases far superior to nanoparticles or their assemblies. Nanotubes or wires can be grown by hydrothermal or template methods, or even more elegantly, by self-organizing anodic oxidation. The latter is not limited to TiO2 but to a full range of other functional oxide structures on various metals and alloys. These advanced and doped morphologies can be grown on conducti
Date: Tue, 18.10.2016
Time: 16:00
Location:Technische Universität Wien, Institut für Angewandte Physik, E134 yellow tower „B“, 5th floor, Sem.R. DB gelb 05 B (room number DB05L03), 1040 Wien, Wiedner Hauptstraße 8-10
Contact:Univ.Prof. Dr. Ulrike Diebold

On-shell conditions in theories with flavor mixing
Speaker:Maximilian Löschner (Univ. Wien)
Abstract:In this talk, I will present a derivation of the on-shell renormalization conditions in theories where mixing among different particle flavors or families can not be neglected. This subject is already important for precision calculations in the Standard Model, but even more so in models beyond, e.g. when neutrino masses and an unspecified number of right-handed neutrinos needs to be taken into account. The derivation will be carried out for scalar and fermionic fields in theories with and without parity conservation. I will also discuss the specifics of Majorana fermions and show how these conditions are implemented in renormalization.
Date: Tue, 18.10.2016
Time: 16:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, H. Neufeld

Singularities in General Relativity
Speaker:Bernd Schmidt (Albert Einstein Inst., Golm)
Abstract:im Rahmen des Seminars in Geometric Analysis and Physics (GAP Seminar)
Date: Thu, 20.10.2016
Time: 10:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock, 1090 Wien
Contact:V. Branding (Fak. Math, U.V.) D. Fajman (Fak. Phys, U.V.) J. Joudioux (Fak. Phys, U.V.)

Optimization of STIRAP-based state transfer under dissipation
Speaker:Yingdan Wang (ITP, Chinese Academy of Sciences )
Abstract:We quantify the influence of nonadiabatic leakage and system dissipation on the transfer fidelity with counterintuitive pulses. We found that optimizing transfer time rather than coupling profiles, leads to a significant improvement of the transfer fidelity. The upper bound of the fidelity has been found as a simple analytical function of system cooperativities. We also provide a systematic approach to reach this upper bound efficiently. By including the dissipation of all the parties, our results are widely applicable to quantum state engineering and are particularly relevant for solid-state devices, with typically non-negligible dissipation of the source and the target systems.
Date: Thu, 20.10.2016
Time: 10:30
Location:Atominstitut, Stadionallee 2, Bibliothek, 1020 Wien
Contact:Peter Rabl

Transition conditions for isolated self-gravitating bodies
Speaker:Bernd Schmidt (Albert Einstein Inst., Golm)
Abstract:Im Rahmen des Literaturseminars der Gravitationsphysik: For freely floating self-gravitating bodies the boundary conditions on physical grounds are: the vanishing of the normal stress at the boundary for all times. We expect that these conditions together with initial data determine a unique solution of the evolution equations. However, if the density of the matter at the surface of the body is positive, further "transition conditions" are needed to imply sufficient differentiability of the solution inside and outside the body. I will discuss the origin of these conditions first for a simple model problem and then for self-gravitating bodies in Newton's and Einstein's theory of gravity.
Date: Thu, 20.10.2016
Time: 14:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien
Contact:P.T. Chrusciel

BTZ black holes, warped AdS3 black holes and flat space cosmologies in higher derivative gravity theories
Speaker:Celine Zwikel (Brussels U. & Solvay Inst.)
Abstract:In this talk, we consider warped AdS3 black holes, BTZ black holes and flat space cosmologies in generic higher derivative gravity theories in 2+1 dimensions. Using the covariant phase space formalism, we prove the match between the bulk Iyer-Wald entropy of these solutions and the field theory entropy for the corresponding asymptotic symmetry algebras (CFT2, Warped CFT2, BMS3). This talk is based on the following papers: arXiv:1604.02120 and arXiv:1602.09089.
Date: Thu, 20.10.2016
Time: 16:00
Location:SEM 136, TU Wien, Freihaus, 10th floor (Wiedner Hauptstr. 8-10, A-1040 Vienna)
Contact:Daniel Grumiller

Smart interfaces in biophysics: From functional molecules to biomimetics
Speaker:Prof. Dr. Christine Selhuber-Unkel (Institute for Materials Science, Christian-Albrechts-Universität zu Kiel, Kiel/Germany)
Abstract:Smart interfaces are essential to many biomedical applications, as they can provide functional cellular environments by a variety of mechanisms, including chemical and physical stimuli. I will present results on how cells can be controlled, investigated and mimicked by such smart interfaces. These include, for example, biocompatible photoresponsive interfaces for dynamically controlling cell adhesion with molecular precision, as well as surface-­‐integrated force sensors for quantifying cellular mechanotransduction. In addition, I will introduce a biomimetic concept for transferring cellular functions into novel adaptive interfaces.
Date: Fri, 21.10.2016
Time: 09:00
Location:Technische Universität Wien, TU-Bibliothek, Resselgasse 4, 5th floor, lecture hall
Contact:Univ.Prof.Dr. Friedrich Aumayr

A Quantum Gas in a Box
Speaker:Nir Navon (University of Cambridge)
Abstract:For the past two decades harmonically trapped ultracold atomic gases have been used with great success to study fundamental many-body physics in a flexible experimental setting. Recently, we achieved the first atomic Bose-Einstein condensate in an essentially uniform potential of an optical-box trap [1], which has opened new possibilities for closer connections with condensed-matter systems and theories of the many-body problem that generally rely on the translational symmetry of the system. I will present two directions that we have recently explored with this new system: the study of the (Kibble-Zurek) dynamics of spontaneous symmetry breaking in a quenched homogeneous gas [2], and the emergence of turbulence in a periodically driven quantum gas [3]. [1] A. L. Gaunt et al., Phys. Rev. Lett. 110, 200406 (2013) [2] N. Navon et al., Science 347, 167 (2015) [3] N. Navon et al., Nature (in press, 2016), arXiv:1609.12701
Date: Fri, 21.10.2016
Time: 15:30
Location:Atominstitut, Hörsaal, Stadionallee 2, Wien 2
Contact:J. Schmiedmayer