Calendar of Physics Talks Vienna

CoQuS Colloquium - Seminar Talk by Myungshik Kim
Speaker:Myungshik Kim (CoQuS)
Abstract:Single-boson level operations in quantum optics Dirac writes that the mathematical structure of bosonic operations is one of the most fundamental results of quantum mechanics, which enables a unification of the wave and corpuscular theories of light. The technology to manipulate photons has been developed to subtract or to add single quanta from/to a bosonic system. In this talk, we discuss what we can do with the single-boson level operations for a test of principles of quantum mechanics and for quantum state engineering.
Date: Mon, 15.05.2017
Time: 16:30
Duration: 120 min
Location:Atominstitut, Stadionallee 2, 1020 Vienna
Contact:CoQuS Team

Path integrals for Wilson lines and Wilson surfaces
Speaker:Anton Alekseev (University of Geneva)
Abstract:im Rahmen des Seminars für Mathematische Physik: Wilson lines in gauge theory admit several path integral presentations based on the theory of coadjoint orbits. We will discuss an interpretation of these theories as 2-dimensional sigma-models using equivariant cohomology and consider toy model applications in 2-dimensional Yang-Mills theory.
Date: Tue, 16.05.2017
Time: 14:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:S. Fredenhagen, H. Steinacker

Interactions of MHC Class I proteins discovered on antibody-micropatterned surfaces
Speaker:Cindy Dirscherl & Sebastian Springer (Jacobs University Bremen, Germany)
Abstract:Microcontact printing allows us to generate patterns of antibodies on glass surfaces. If cells that express GFP tagged 'target' membrane proteins are grown on such antibody micropatterns, the target membrane protein become arranged according to the printed patterns, as seen by fluorescence microscopy. We have applied this approach to Major Histocompatibility Class I (MHC I) proteins, the peptide-binding membrane receptors that play a central role in the adaptive immune system. We have shown that they can be specifically captured on micropatterns in living cells, and that they remain fully functional and even bind their specific peptide ligands. We have expanded this approach towards a two-hybrid in cis interaction assay for membrane proteins, where one protein is tagged with an antibody epitope and the other with GFP, and we have discovered that MHC I proteins form such in cis interactio
Date: Tue, 16.05.2017
Time: 16:00
Location:Tuesday, 16th May 2017, 16:00 s.t. 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. G. Schütz

Magneto-optical infrared studies of the Weyl semimetals TaAs, TaP and NbP
Speaker:A. V. Pronin (1. Physikalisches Institut, Universität Stuttgart, Germany)
Abstract:We report on infrared and magnetotransport measurements of the Weyl semimetals TaAs, TaP, and NbP in zero magnetic field and in fields of up to 30 T. In all compounds, we can reliably trace the optical transitions between different Landau levels. The transition frequencies demonstrate a square-root field dependence, typical for the linearly dispersed bands. In TaP, we can also see a sizeable shift of the plasma edge in magnetic field and interplay between this plasma-edge shift and the Landau-level transitions. We compare the optical spectra of the three compounds, describe the spectra by the recent models for the (magneto)optical response of Weyl semimetals, and extract such parameters as the Fermi velocities of the carriers in the Weyl bands and the positions of the Fermi levels relative to the Weyl points.
Date: Wed, 17.05.2017
Time: 16:00
Duration: 45 min
Location:Seminarraum DC rot 07 (Freihaus, roter Bereich, 7. OG), Wiedner Hauptstraße 8-10, 1040 Wien
Contact:Andrei Pimenov

The hunt for the elusive photon-photon elastic scattering: the PVLAS experiment and more
Speaker:Prof. Edoardo Milotti (Dipartimento di Fisica, Università di Trieste and INFN-Sezione di Trieste)
Abstract:Photon-photon scattering is forbidden in classical electromagnetism, but it becomes possible in quantum field theory thanks to the fluctuations of charged matter fields. The first theoretical calculations are associated with the names of Euler, Heisenberg, and Weisskopf, and date back to more than 80 years ago, but to date a laboratory measurement is still missing. The predicted effect is extremely minute with visible photons, and measurements require an exceedingly high level of precision. Currently, a bunch of experimentalists are painstakingly trying to get to the required level of precision. There is much at stake: by reaching this difficult experimental goal we could open a new window on the nature of quantum vacuum, and maybe discover some essential clues on dark matter. In this talk...[complete last paragraph available at https://indico.smi.oeaw.ac.at/event/217/]
Date: Wed, 17.05.2017
Time: 17:00
Duration: 60 min
Location:Stefan-Meyer-Institut, Boltzmanngasse 3, 1090 Wien, Seminarraum 3-2-08 (2. Stock)
Contact:Prof. Dr. Eberhard Widmann, Dr. Martin Simon

Gravitational Memory, Information, and Black Holes
Speaker:Stefan Hollands (Leipzig)
Abstract:A burst of gravitational radiation passing through an arrangement of freely falling test masses far from the source will cause a permanent displacement of the masses, called the ``gravitational memory''. It has recently been found that this memory is closely related to the change in the so called ``super-translation'' charge carried by the spacetime, where ``super-translations'' here refer to an unexpected enlargement of the asymptotic symmetries of general relativity beyond the expected asymptotic Poincare-transformations, known already since the work of Bondi et al. in the early 60s (no relation with ``supersymmetry''). I will describe these concepts from an intuitive perspective and point out that super-translations, as well as gravitational memory, are a phenomenon that is unique to relativity in 3+1, but not higher, dimensions. I close the talk by outlining the relation ...
Date: Thu, 18.05.2017
Time: 14:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien
Contact:P.T. Chrusciel

Unifying inflation with the axion, dark matter, baryogenesis and the seesaw mechanism
Speaker:Carlos Tamarit (IPPP Durham)
Abstract:A minimal extension of the standard model (SM) with a single new mass scale and providing a complete and consistent picture of particle physics and cosmology up to the Planck scale is presented. We add to the SM three right-handed SM-singlet neutrinos, a new vectorlike color triplet fermion, and a complex SM-singlet scalar σ that stabilizes the Higgs potential and whose vacuum expectation value at ∼1011  GeV breaks lepton number and a Peccei-Quinn symmetry simultaneously. Primordial inflation is produced by a combination of σ (nonminimally coupled to the scalar curvature) and the SM Higgs boson. Baryogenesis proceeds via thermal leptogenesis. At low energies, the model reduces to the SM, augmented by seesaw-generated neutrino masses, plus the axion, which solves the strong CP problem and accounts for the dark matter in the Universe.
Date: Thu, 18.05.2017
Time: 14:00
Duration: 60 min
Location:HEPHY, Nikolsdorfer Gasse 18, 1050 Wien - Bibliothek
Contact:Josef Pradler

Strongly coupled Weyl semi-metals
Speaker:Francisco Pena-Benitez (INFN Perugia)
Abstract:In this talk I will review the main properties of Weyl semimentals. Including a recent experiment which claims the observation of the so-called mixed gauge-gravitational anomaly in a Weyl semimetal. Then I’ll discuss a holographic model that realize some of the features of the these materials. In particular, I will analyze the electrical conductivity, its frequency dependence and phase diagram; I will finish discussing some predictions of the model.
Date: Thu, 18.05.2017
Time: 16:00
Duration: 60 min
Location:10th floor seminar room in yellow tower of TU Wien Freihaus (Wiedner Hauptstrasse 8-10, A-1040 Vienna)