Calendar of Physics Talks Vienna

Search for new strain-induced multiferroics with high critical temperatures
Speaker:S. Kamba (Academy of Sciences of the Czech Republic, Prague )
Abstract:Recently, we have experimentally verified that biaxial strain can induce the ferroelectric (FE) and ferromagnetic state in epitaxial thin film of EuTiO3, which is paraelectric and antiferromagnetic in the bulk form. [1] We have found that 1% tensile strain in EuTiO3/DyScO3 films induces ferroelectricity at 250 K and ferromagnetism at 4.2 K. My talk will be devoted to the experimental search for other strain-induced multiferroics with higher critical temperatures than EuTiO3. We will focus on the study of EuO, Ca3Mn2O7 and SrMnO3 thin films, which were recently predicted to be multiferroic using first principles calculations.[2-4] Finally, I will speak about THz and infrared studies of  phase of Fe2O3. This material crystallizes in the non-centrosymmetric orthorhombic Pna21 space group, but no ferroelectricity was reported in this system. Below 500 K, it becomes ferrimagnetic and near 100 K it undergoes a phase transition to an incommensurately modulated magnetic structure. Below 100 K we found in IR spectra a new broad reflection band near 70 cm-1. Its intensity increases on cooling, while the intensity of the phonon near 90 cm-1 decreases. This is an evidence of a coupling between the new excitation and the polar phonon. Due to the absence of a structural phase transition at 100 K, the new polar excitation reminds an electromagnon. [1] J.H. Lee et al. Nature, 466, 954 (2010); ibid 476, 114 (2011). [2] E. Bousquet, N.A. Spaldin et al., Phys. Rev. Lett. 104, 037601 (2010). [3] J.H. Lee and K.M. Rabe, Phys. Rev. Lett. 104, 207204 (2010). [4] N.A. Benedek and C.J. Fennie, Phys. Rev. Lett. 106, 107204 (2011).
Date: Wed, 30.05.2012
Time: 16:00
Duration: 45 min
Location:Seminarraum 138B, 7. OG, roter Bereich, Freihausgebäude, TU Wien
Contact:Andrei Pimenov

Mass Effects in DIS
Speaker:Johannes Blümlein (DESY, Zeuthen)
Abstract:im Rahmen des Teilchenphysikseminars
Date: Thu, 31.05.2012
Time: 14:15
Duration: 60 min
Location:Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, H. Neufeld

The gravitational two body problem in the post-Newtonian approximation via effective field theory methods
Speaker:Riccardo Sturani (Urbino)
Abstract:im Rahmen des Literaturseminars
Date: Thu, 31.05.2012
Time: 14:15
Duration: 60 min
Location:Arbeitsgruppe: Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock
Contact:R. Beig

Black hole thermodynamics under the microscope
Speaker:Kevin Falls (University of Sussex)
Abstract:We discuss the thermodynamics of black holes from a Wilsonian perspective with the help of the renormalization group. Conditions are formulated under which the thermodynamic properties of black holes persist even under the renormalization group evolution of couplings. From the thermodynamical consistency of our setting we deduce that the relevant renormalization group scale must be set by the horizon area of the black hole, which acts as a diffeomorphism invariant cutoff. Provided, additionally, that gravity becomes asymptotically safe at high energies, we find the existence of a smallest black hole mass and, at high energies, reproduce conformal scaling behaviour.
Date: Thu, 31.05.2012
Time: 16:00
Location:TU Wien (Wiedner Hauptstr. 8-10), yellow area, 10th floor, seminar room E136
Contact:Daniel Grumiller

How deterministic is gene transcription
Speaker:Manuel Schölling (Med.Univ.Wien)
Abstract:im Rahmen der gemeinsam veranstalteten Seminare "Komplexe Stochastische Systeme" (Univ. Wien) und "Analyse Komplexer Systeme" (Med.Univ.Wien)
Date: Fri, 01.06.2012
Time: 14:15
Duration: 90 min
Location:Medizinische Universität Wien, Informatikbibliothek Bauteil 88, E 03, Spitalgasse 23
Contact:H. Hüffel, Stefan Thurner

The effect of the earth's gravity and rotation on the quantum mechanical phase of the neutron
Speaker:Sam WERNER (Neutron Physics Group, NIST Gaithersburg)
Date: Fri, 01.06.2012
Time: 15:30
Location:TU Wien Atominstitut, Hörsaal, Stadionallee 2, 1020 Wien
Contact:H. Rauch