Freitag, 2. Mai 2025 17:00 Uhr  Probing quantum gravity at all scales

Prof. Dr. Astrid Eichhorn, Institut für Theoretische Physik, Universität Heidelberg

What is the fundamental quantum structure of spacetime? This question constitutes a persistent challenge in physics and several candidate theories of quantum gravity have been developed in response to this challenge. However, experimental tests of these theories are extremely rare, because the typical scale of quantum gravity, the Planck scale, is much smaller than distance scales that can be probed experimentally.

To confront quantum theories of gravity with observations, we therefore require ``lever arms" which translate predictions of quantum gravity at the Planck scale into testable predictions at much larger scales.

In this talk, I will introduce asymptotically safe quantum gravity as an example for which such a lever arm exists, which is the Renormalization Group flow of couplings - a ``microscope" for quantum field theories, which enables us to translate Planck-scale predictions to testable predictions, for instance for properties of elementary particles in the Standard Model and beyond, for example for dark matter.

A light approach to Dark Matter: the DELight experiment

Dr. Francesco Toschi, KIT, Karlsruhe

Dienstag, 29. April 2025 16:30 Uhr  The build-up of galactic nuclei: how do black holes get there?

Nadine Neumayer, MPIA The centers of massive galaxies are special in many ways, not least because apparently all of them host supermassive black holes. Since the discovery of a number of relations linking the mass of this central black hole to the large scale properties of the surrounding galaxy bulge it has been suspected that the growth of the central black hole is intimately connected to the evolution of its host galaxy. However, at lower masses, and especially for bulgeless galaxies, the situation is much less clear. Interestingly, these galaxies often host massive star clusters at their centers, and unlike black holes, these nuclear star clusters provide a visible record of the accretion of stars and gas into the nucleus. I will present our ongoing observing programmes of the nearest nuclear star clusters, including the Milky Way Center, and the stripped galaxy nuclei Omega Centauri and M54 (still at the center of the Sagittarius dwarf galaxy). These observations provide important information on the formation mechanisms of nuclear star clusters, allow us to measure potential black hole masses and give clues on how black holes get to the centers of galaxies.

Mittwoch, 7. Mai 2025 16:30 Uhr  tba

Dr. Torsten Zache, Institut für Quantenoptik und Quanteninformation, Innsbruck