Physikalisches Kolloquium

Programm für das Sommersemester 2024

Tuesdays, 16 Uhr c.t.

Institut für Physik

HS KPH
16.04.24Prof. Dr. Ulrich Stroth, Max Planck Institute for Plasma Physics, Garching
In times of a shift towards a low CO2 energy supply and boosted by the recent success of laser fusion, the advantages of nuclear fusion in general have come into the focus of politics and private investors as an attractive energy source. This talk introduces the concept of magnetic fusion and outlines the path to a fusion reactor. The perspectives of magnetic fusion will be compared with those of laser fusion and the concepts of startups. The role of plasmas, in which energy is obtained from the fusion of hydrogen isotopes, and their physical properties are explained.
Slides here...
16:15 Uhr s.t., HS KPH

30.04.24Prof. Dr. Joacim Rocklöv, Heidelberg University
In this talk I will introduce infectious diseases and their sensitivity to climate variability and change. I will describe and contrast experimental evidence with empirical observations and data. In the talk I will discuss systems and interactions enabling introduction and transmission of emergent vectors, hosts, and pathogens. I will further give examples of how mathematical process-based models and machine learning approaches are used and how they can be applied to study patterns and responses to these changes. Finally, I will talk about novel applications of machine learning in surveillance and early warnings, as well as the evaluation of interventions to guide effective responses.
Slides here...
16:15 Uhr s.t., HS KPH

07.05.24Prof. Dr. Michael Kramer, Max Planck Institute for Radio Astronomy, Bonn
Pulsars, the natural beacons of the universe, put physics to extreme test. As neutron stars, they are not only the densest objects in the observable universe, but they also serve as high-precision laboratories for testing the general theory of relativity. Pulsars not only allow the observation of predicted effects that cannot be observed by other methods, but they provide also extremely precise tests of the properties of gravitational waves. The latest results even use pulsars as galactic gravitational wave detectors, which detect a continuous "hum" of space-time. This buzz is, most likely, caused by the merging of supermassive black holes in the early universe. The talk gives an overview of the latest results and an outlook into the future.
Slides here...
16:15 Uhr s.t., HS KPH

aktuell

14.05.24Prof. Dr. Jochem Marotzke, Max Planck Institute for Meteorology, Hamburg

The cause and the future of climate change 

I will first illustrate two key conclusions from the latest report of the Intergovernmental Panel on Climate Change, IPCC, from 2021. The first states that “it is unequivocal that human influence has warmed the atmosphere, ocean and land”. The second states that “global warming of 1.5°C and 2°C will be exceeded during the 21st century unless deep reductions in CO2 and other greenhouse gas emissions occur in the coming decades.” I will then explain how these results built on the work of Klaus Hasselmann and Syukuro Manabe, respectively, who shared the Nobel Prize in physics in 2021. The second of the statements was made possible through remarkable research progress during the past decade, and I will demonstrate how the scientific process within the IPCC turned a seeming scientific crisis into substantial progress. Finally, I will look at the still unsolved problem of understanding the future of the Atlantic Ocean circulation and how we tackle this problem in current research.
Slides here...
16:15 Uhr s.t., HS KPH

zukünftige Termine
21.05.24Prof. Dr. Cristian Micheletti, SISSA, Trieste, Italy
Sampling equilibrium ensembles of dense polymer mixtures is a paradigmatically hard problem in computational physics, even in lattice-based models. For instance, using real-space Monte Carlo to sample polymer systems becomes impractical for increasing size, rigidity, and density of the chains. In response to these challenges, we introduce and apply a formalism to recast polymer sampling as a quadratic unconstrained binary optimization (QUBO) problem [1]. Thanks to this mapping, dense systems of stiff polymers on a lattice can be efficiently sampled with classical QUBO solvers, resulting in more favourable performance scaling compared to real-space Monte Carlo [2]. Tackling the same problems with the D-Wave quantum annealer leads to further performance improvements [2]. As an application, we discuss the use of the quantum-inspired encoding on a hitherto untackled problem, namely the linking probability of equilibrated melts of ring polymers, for which we unveil counterintuitive topological effects. References [1] C.Micheletti, P. Hauke and P. Faccioli, "Polymer physics by quantum computing", Phys. Rev. Lett. 127, 080501 (2021) [2] F. Slongo, P. Hauke, P. Faccioli and C. Micheletti "Quantum-inspired encoding enhances stochastic sampling of soft matter systems", Sci. Adv. 9, art. no adi0204 (2023)
Slides here...
16:15 Uhr s.t., HS KPH

28.05.24Prof. Dr. Ingo Rehberg, University of Bayreuth
Spherical magnets are an invaluable but affordable physics toy! While vividly demonstrating chemical, physical and mathematical problems, they can also greatly inspire creativity: Questions concerning the favoured state of dipole cluster configurations lead – via an encounter with tipping points – to the invention of magnetic gears based on degenerate continua. Open source animations and patent-free hardware to play with shall garnish this triptychon.
Slides here...
16:15 Uhr s.t., HS KPH

04.06.24Prof. Dr. Claudia Felser, Max Planck Institute for Chemical Physics of Solids, Dresden
Topology, a well-established concept in mathematics, has nowadays become essential to describe condensed matter. At its core are chiral electron states on the bulk, surfaces and edges of the condensed matter systems, in which spin and momentum of the electrons are locked parallel or anti-parallel to each other. Magnetic and non-magnetic Weyl semimetals, for example, exhibit chiral bulk states that have enabled the realization of predictions from high energy and astrophysics involving the chiral quantum number, such as the chiral anomaly, the mixed axial-gravitational anomaly and axions. The potential for connecting chirality as a quantum number to other chiral phenomena across different areas of science, including the asymmetry of matter and antimatter and the homochirality of life, brings topological materials to the fore.
Slides here...
16:15 Uhr s.t., HS KPH

11.06.24Dr. Karen Alim, TU München
Propagating, storing and processing information is key to take smart decisions – for organisms as well as for autonomous devices. In search for the minimal units that allow for complex behaviour, the slime mould Physarum polycephalum stands out by solving complex optimization problems despite its simple make-up. Physarum’s body is an interlaced network of fluid-filled tubes lacking any nervous system, in fact being a single gigantic cell. Yet, Physarum finds the shortest path through a maze. We unravel that Physarum’s complex behaviour emerges from the physics of active flows shuffling through its tubular networks. Flows transport information, information that is stored in the architecture of the network. Thus, tubular adaptation drives processing of information into complex behaviour. Taking inspiration from the mechanisms in Physarum we outline how to embed complex behaviour in active microfluidic devices and how to program human vasculature.
Slides here...
16:15 Uhr s.t., HS KPH

18.06.24Dr. Thomas Cocolios, KU Leuven, Belgium
Nuclear medicine is currently experiencing some major changes and developments: Lu-177 has become a standard radionuclide for patient care, in particular with Lutathera® and Pluvito®, two recently marketed drug for endocrine and prostate cancers, respectively. Those successes are but the tip of the iceberg of possibilities: with 3000 radionuclides synthesized in the laboratory, it seems unbelievable that only a handful are actually used in medical applications. This is mostly due to the absence of a supply pipeline to support research until their production is picked up by the industry. To break that paradigm, CERN has established the MEDICIS facility (MEDical Isotopes Collected from ISolde), where the techniques developed for the last 50 years on radioactive ion beams are now applied to produce medical radionuclides for research. The success of the development of non-carrier-added Sm-153 has led it to first clinical trials in 2024. At the European level, this has triggered a new consortium, federated around MEDICIS but with a larger reach, as PRISMAP, the European medical radionuclide programme.
Slides here...
16:15 Uhr s.t., HS KPH

25.06.24Prof. Dr. Klaus Blaum, Max-Planck Institute for Nuclear Physics
The four fundamental interactions and their symmetries, the fundamental constants as well as the properties of elementary particles like masses and moments, determine the basic structure of the universe and are the basis for our so well tested Standard Model (SM) of physics. Performing stringent tests on these interactions and symmetries in extreme conditions at lowest energies and with highest precision by comparing, e.g., the properties of particles and their counterpart, the antiparticles, will allow us to search for physics beyond the SM. Any improvement of these tests beyond their present limits requires novel experimental techniques. An overview is given on recent mass and g-factor measurements with extreme precision on single or few cooled ions stored in Penning traps. Among others the most stringent test of bound-state quantum electrodynamics could be performed. Here, the development of a novel technique, based upon the coupling of two ions as an ion crystal, enabled the most precise determination of a g-factor difference to date. This difference, determined for the isotopes 20,22Ne9+ with a relative precision of 5 × 10−13, improved the precision for isotopic shifts of g factors by about two orders of magnitude. Our latest results on precision measurements with exotic ions in Penning traps will be presented.
Slides here...
16:15 Uhr s.t., HS KPH

02.07.24Prof. Dr. Laura Kreidberg, Max Planck Institute for Astronomy, Heidelberg
The recent launch of the James Webb Space Telescope (JWST) has revolutionized the field of exoplanet atmosphere characterization, thanks to its unprecedented sensitivity and broad wavelength coverage. In this talk, I will give a tour of the latest JWST results for transiting exoplanets, from gas giants down to rocky worlds. For the largest planets, I'll focus on the complex physical processes recently revealed in their atmospheres, including photochemistry, 3D effects, and cloud formation. Pushing down to smaller worlds, I'll share the first measurements of chemical composition for the elusive sub-Neptune population; and finally give an update on which (if any) rocky planets have atmospheres at all.
Slides here...
16:15 Uhr s.t., HS KPH

09.07.24Dr. Kerem Çamsarı, University of California, Santa Barbara
tba
16:15 Uhr s.t., HS KPH

16.07.24Dr. Frank Saueressig, Radboud University, NL
Fusing the principles of general relativity and quantum mechanics in a consistent theoretical framework still constitutes one of the main open challenges in theoretical physics today. Over the last decades, the gravitational asymptotic safety program has taken significant steps towards achieving this goal. A central virtue, driving the success of the approach, is its conservative nature: the program builds on well-established principles of quantum field theory and extends them in a rather minimalistic way. In this talk, we will review the key developments in the program, building up to its present status. I will also attempt to give an outlook on the challenges that need to still be addressed in the future.
Slides here...
16:15 Uhr s.t., HS KPH

16.07.24Prof. Dr. Reinhard Noack, Philipps University Marburg
Colloquium in honor of Prof. Dr. Peter G. J. van Dongen and Prof. Dr. Martin Reuter (Part 2): Correlated Electrons from Zero to Infinite Dimensions: Early Days of KOMET in Mainz
16:15 Uhr s.t., HS KPH

Koordination: Kontakt:

Prof. Dr. Hans Jockers
Institut für Physik
jockers@uni-mainz.de

Prof. Dr. Concettina Sfienti
Institut für Kernphysik
sfienti@uni-mainz.de

Caroline Hoffmann
Sekretariat Prof. Dr. Hans Jockers
Institut für Physik
choffman@uni-mainz.de

Sibylle Wittek
Sekretariat Prof. Dr. Concettina Sfienti
Institut für Kernphysik
swittek@uni-mainz.de