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
Dr. Florian Meinert, 5th Institute of Physics, University of Stuttgart Circular Rydberg Atoms for Quantum Simulation Dr. Florian Meinert 5th Institute of Physics, University of Stuttgart Highly excited atoms named after Janne Rydberg have played an important role throughout the history of atomic physics. In recent years, their strong mutual interaction was key to realize quantum computers and simulators with individual atoms trapped in optical tweezer arrays. Coherence times or gate fidelities reached on these devices are, however, fundamentally limited by the lifetime of the Rydberg electron. Orders of magnitude longer lived Rydberg states can be created by spinning up the electron as much as quantum mechanics allows for. Such circular Rydberg states have already led to Nobel-prize winning works on fundamentals of atom-light interaction. In our experiments, we generate, coherently control, and trap individual Strontium circular Rydberg atoms in optical tweezer arrays. Along this endeavor, we have recently gained access to giant trapped circular Rydberg states with principal quantum numbers up to n=103 and measured record lifetimes of more than 10 milliseconds. This is achieved via Purcell suppression of blackbody radiation at room temperature. Exploiting the second valence electron available in Strontium further allowed us to couple the circular Rydberg electron to inner shell excitations, which can be used for local optical control. These results now pave the way for quantum information processing and sensing utilizing the combination of extreme lifetimes and giant Rydberg blockade.
