CPT

Calendar of Physics Talks Vienna

Breaking translations, keeping SUSY
Speaker:Matthew Roberts (Imperial College London)
Abstract:Despite supersymmetry being the square root of the Poincare algebra, it is possible to construct SUSY field theories which break some space-time symmetries. This preserves calculational control even when going to strong coupling. I will discuss general deformations, as well as special cases which come from maximally supersymmetric field theories, and construct holographic duals.​
Date: Tue, 10.03.2020
Time: 13:45
Duration: 60 min
Location: Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:S. Fredenhagen, D. Grumiller

The covariance of physical laws in quantum reference frames
Speaker:Caslav Brukner (Univ. Wien)
Abstract:Every observation in physics is made with respect to a frame of reference.In practise, we use real physical systems as reference frames and as such they obey quantum mechanical laws.I will introduce a general method to quantise reference frame transformations,which generalises the usual reference frame transformation to a “superposition of coordinate transformations”.I will describe how states, measurements,and dynamical evolutions transform between different quantum reference frames.While entanglement and superposition will be shown to be frame-dependent features,the form of the dynamical physical laws(e.g.the Schrödinger equation)remain the same in all frames,which generalises the notion of covariance of physical laws to quantum reference frames.I will end with two applications of our results: a definition of the rest frame for a quantum particle in a superposition of velocities ....
Date: Tue, 10.03.2020
Time: 16:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-HS, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, S. Plätzer, M. Procura

Classical de Sitter string backgrounds and swampland conjectures
Speaker:David Andriot (TU Wien)
Abstract:Solutions of string theory with a four-dimensional de Sitter space-time could serve as an interesting starting point to build cosmological models of the early universe, or the present one. Obtaining such solutions in a well-controlled manner is however notoriously difficult. This has recently led to various conjectures, in the context of the swampland program, that strongly constrain the existence of de Sitter solutions in string effective models, with drastic consequences regarding single field inflation or quintessence. Focusing on classical string backgrounds, these conjectures can be precisely tested, with sharp no-go theorems, as well as promising counter-examples, that could eventually serve in stringy cosmological models. We will present an overview and new results on this topic.
Date: Thu, 12.03.2020
Time: 16:00
Duration: 60 min
Location:TU Wien, Wiedner Hauptstraße 10, Yellow Area, Seminar Room 10th floor
Contact:Anton Rebhan

The Semigroup Approach to Evolution Equations: An Overview
Speaker:Horst R. Beyer (Instituto Tecnológico Superior de Uruapan, Michoacán, México)
Abstract:The talk gives an overview of the application of abstract operator theoretic methods, from the area of semigroups of operators, to evolution equations, in particular, of the hyperbolic type. For the case of time-dependent linear and quasi-linear evolution equations, the talk focuses on applications of the late Tosio Kato’s most recent theorems. Complete details are given in the speaker’s book, ”Beyond partial differential equations: On linear and quasi-linear abstract hyperbolic evolution equations”, Springer Lecture Notes in Mathematics, LNM 1898, Springer: Berlin, 2007
Date: Fri, 13.03.2020
Time: 13:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Straße 17, Seminarraum 218, 2. Stock
Contact:D. Fajman, R. Beig