Current seminars

In addition to the Vienna relativity seminars, the calendar above sometimes contains other events of interest to members of the relativity group. The seminars of the Vienna relativity group are listed below.

Location (unless indicated otherwise): Währinger Str. 17
- Room 218 on the 2nd floor for standard seminars, and
- Common room, first floor, for lunch seminars. Unless explicitly stated otherwise, the regular (not-lunch) relativity seminars take place in Room 218 2nd floor, Währingerstrasse 17.

The Mathematical Physics Seminars take place on Tuesdays at 14.15.

The Particle Physics Seminars take place on Tuesdays at 16.15.

  • Thursday, June 14, 14:00, Gernot Heißel (Vienna): From analytical to numerical relativity

Abstract: I am going to present the research I have done for my Master’s and my PhD theses.
For the former, at the University of Vienna, I worked with Mark Heinzle on spatially homogenous cosmology and dynamical systems. We determined the past and future asymptotic dynamics of a particular class of models, locally rotationally symmetric Bianchi type VIII with an anisotropic fluid, and investigated the question if anisotropic matter matters. It does!
For the latter, at Cardiff University and in the LIGO Scientific Collaboration, I worked with Mark Hannam on initial data for black hole simulations. I will explain what trumpet initial data is and why it is of interest, in particular with regards to binary black hole simulations for gravitational wave extraction, and how this ties in with the LSC’s task of detecting gravitational waves in the broader context. I will present our numerical approach to derive trumpet initial data for Schwarzschild and extreme Kerr black holes, and argue that it should be generalisable to slow Kerr as well.

  • Thursday, June 21, 14:00, Jahanur Hoque (Chennai): Gravitational waves in deSitter background

Abstract: Cosmological observations have established that our universe has positive cosmological constant. A positive cosmological constant profoundly alters the asymptotic structure of space-time. In this talk, we discuss the linearized gravitational field produced by compact sources in the background with positive cosmological constant -- de Sitter space. Using the covariant phase space formalism, we obtain the quadrupole formula in such a setting. We also show that the energy flux of gravitational waves measured at future null infinity is the same as that measured across the cosmological horizon of the compact source. To get an order of estimate we also discuss power radiated by a binary system in de Sitter background.

  • Monday, June 25, 14:00, Carla Cederbaum (Tuebingen): On extensions of CMC-Bartnik data

Abstract: Bartnik data are a Riemannian 2-sphere of positive Gaussian curvature equipped with a non-negative function H to be thought of as its mean curvature in an ambient Riemannian 3-manifold. Mantoulidis and Schoen suggested a construction of asymptotically flat Riemannian 3-manifolds of non-negative scalar curvature which allows to isometrically embed given Bartnik data of vanishing mean curvature, i.e. H=0. They use their construction to explore — and disprove — stability of the Riemannian Penrose inequality. In collaboration with Cabrera Pacheco, McCormick, and Miao, we adapt their construction to constant mean curvature (CMC) Bartnik data, i.e. H=const.>0. Moreover, with Cabrera Pacheco and McCormick, we extend their construction to the asymptotically hyperbolic setting both for H=0 and for H=const.>0 Bartnik data.
I will present the construction as well as the motivation for such a construction which is related to Bartnik’s quasi-local capacity/mass functional and its minimizing properties.

  • Tuesday, June 22, lunch seminar, 13:00, David Edward Bruschi (Vienna): On the weight of entanglement: the role of quantum correlations in physics at the overlap of relativity and quantum science

Abstract: In recent years, quantum correlations have gained a prominent role in many areas of physics, from quantum information science to tests of alternative theories of gravity. Quantum correlations are the core ingredient of many tasks in the most diverse areas of science, such as quantum refrigeration, quantum communication or the Hawking effect. A thorough investigation of the nature of these correlations and their role is paramount to advance our knowledge of nature.
We present a body of work that aims at understanding the role of quantum correlations in phenomena that exhibit genuine relativistic and quantum features. This body of work covers different aspects of relativistic quantum physics, from quantum communication in curved spacetimes, to ultra-precise measurements of the gravitational field and the contributions of quantum correlations in the theory of gravitation. We discuss possible applications and potential attempts for experimental demonstrations.

  • Friday, June 29, 15:00 (at ESI, as part of a joint Analysis, Relativity and Geometry seminar), Andras Vasy (Stanford): Global analysis for linear and nonlinear waves and the stability of Kerr-de Sitter space

Abstract: I will discuss the problem of proving the stability of the family of Kerr-de Sitter (KdS) black holes as solutions of Einstein's vacuum equation: spacetimes evolving from initial data close to those of $(M,g)$ stay globally close to $(M,g)$, and are indeed asymptotic to $(M,g)$ or another nearby member of the KdS family.
I will focus on analytic aspects of this problem together with the choice of a gauge to break the diffeomorphism invariance of Einstein's equation and the role of constraint damping. The analytic framework is that of global non-elliptic Fredholm problems. The main ingredients are, first, the microlocal control of the regularity of waves by means of elliptic, real principal type, and radial point estimates on a suitable compactification of the spacetime; and second, the asymptotic analysis in which model operators and resonance expansions play a role.