Freitag, 10. Juli 2026 17:00 Uhr KINDERKOLLOQUIUM: Regenbogen, teile Deine Farben!
Selim Jochim, Universität Heidelberg
Selim Jochim, Universität Heidelberg
Prof. Ph.D. Stefan Hollands , Theoretische Physik, Universtät Leipzig Negative Energy Prof. Ph.D. Stefan Hollands Theoretische Physik, Universtät Leipzig Ordinarily, the actual energy is not physically significant but only energy differences are. But in general relativity, the absolute energy (density) appears on the right side of the Einstein equations as a component of the stress tensor. In this colloquium I explore how negative energy densities are thereby related to exotic phenomena such as warp drive spacetimes or wormholes. I outline how quantum fluctuations enable negative energies and can be tiny, e.g. in the halos of black holes, or astronomical, e.g. inside black holes. In many interesting cases, the laws of physics limit the amount of possible negative energy. Such laws, such as the quantum null- or quantum dominant energy conditions, can be seen as a fundamental bridge between gravity and quantum information.
Prof. Dr. Christian Glaser, TU Dortmund How Deep Learning and Differential Programming Accelerate Progress in Neutrino Astronomy Prof. Dr. Christian Glaser TU Dortmund Cosmic neutrinos provide a unique probe of the universe's most extreme environments, but their detection is extraordinarily challenging. However, the extremely small flux and cross-section of cosmic neutrinos make their detection extraordinarily challenging and demand the instrumentation of enormous target volumes. In this colloquium, I will discuss how sparse arrays of radio detector stations, deployed in the polar ice sheets, can achieve unprecedented sensitivity to ultra-high-energy (UHE, E > 10¹⁷ eV) cosmic neutrinos. I will explain the detection principle and will introduce the Radio Neutrino Observatory Greenland (RNO-G) - currently under construction - and outline the plans for the next-generation IceCube-Gen2 observatory at the South Pole. I will also present my NuRadioOpt project, which leverages recent advances in deep learning and differentiable programming to enhance the performance of future radio detectors. In particular, real-time AI-based triggering may double the neutrino detection rate, while end-to-end detector optimization through differentiable programming promises substantial improvements in reconstruction accuracy and overall sensitivity.
Colin Snodgrass , University of Edinburgh The first macroscopic interstellar object (ISO) passing through our Solar System, `Oumuamua, was discovered in 2017 and caused a lot of excitement, due to both its novelty and its unexpected properties. The subsequent two discoveries, 2I/Borisov and 3I/ATLAS, appear more like comets. 3I/ATLAS has been observable for most of the last year, and as the first ISO seen in the JWST era has been well studied, and appears to be an ancient object that is significantly older than our Solar System. I will discuss what we have learned about the ISOs seen so far, what the prospects are for this field in the era of Rubin/LSST, and how we could potentially send a spacecraft to see a future visitor up close. To arrange a visit with the speaker during the visit, please contact their host: Markus Hundertmark
Prof. Francesco Scazza, Department of Physics, University of Trieste, Italy Exploring vortex and impurity dynamics in strongly interacting fermionic systems Prof. Francesco Scazza University of Trieste and CNR-INO, Italy Ultracold atoms provide a unique playground for exploring strong correlation phenomena in quantum many-body systems, owing to an exceptional control over the Hamiltonians and long coherent time scales. Recent advances in microscopic optical manipulation have extended our experimental control capabilities down to the level of single atoms or single excitation quanta, providing exciting opportunities to explore quantum many-body problems with a novel perspective. In this talk, I will first present a set of experiments where we have engineered on-demand few- and many-vortex states in strongly interacting fermionic fluids [1,2,3]. By imaging the motion of single quantized vortices, we could shed light on the elementary mechanisms behind quantized vortex energy relaxation in fermionic-pair superfluids, and observe the instability of deterministically prepared vortex crystals, reminiscent of the classical Kelvin-Helmholtz shear-flow instability. In the second part of the talk, I will report on our efforts to construct a new experimental platform in Trieste, aiming to assemble individual ytterbium atoms into mesoscopic many-particle systems with low entropy. Fermionic ytterbium isotopes especially present key features which make them ideal to investigate open questions in quantum impurity problems, such as the formation of Kondo resonances and the competition between quantum dephasing and thermal decoherence for localized spin impurities embedded in a fermionic band. [1] Kwon et al., Nature 600, 64–69 (2021) [2] Del Pace et al., Phys. Rev. X 12, 041037 (2022) [3] Hernandez-Rajkov et al., arXiv:2303.12631 (2023)
