Physikalisches Kolloquium

Programm für das Wintersemester 2023/2024

Tuesdays, 16 Uhr c.t.

Institut für Kernphysik

HS KPH
24.10.23Prof. Tommaso Calarco, Forschungszentrum Juelich
Quantum optimal control has been shown to improve the performance of quantum technology devices up to their limits in terms e.g. of system size and speed of operation. I will review our recent results with a variety of quantum technology platforms, focusing in particular on ultracold atoms, and introduce our newly developed software for automatic calibration of quantum operations - the fundamental building block of next-generation quantum firmware
Slides here...
16 Uhr c.t., HS KPH

31.10.23Prof. Peter Haynes, University of Cambridge
In the last 20 years or so it has been recognised that stratospheric processes have an important effect on the circulation of the troposphere and hence on weather and climate, particularly in the extratropics. The effect is now being exploited in medium range to seasonal weather prediction. The magnitude of the effect is at first surprising given that the mass of stratosphere is only about one fifth of that of the troposphere, but there are important dynamical feedback effects, both in the coupling of troposphere and stratosphere and within the troposphere itself, that amplify the tropospheric response to changes in the stratosphere. This talk will first describe the feedback effects that operate in the extratropics and then move on to consider the tropics, where significant apparent effects of the stratosphere on the troposphere have also become evident. However, the dynamics of the tropical troposphere are very different to that of the extratropical troposphere and it cannot be assumed that the same feedbacks operate in both. Some of the physical and dynamical processes that might account for observed connections between the tropical stratosphere and the tropical troposphere will be discussed.
Slides here...
16:15 Uhr s.t., HS KPH

07.11.23CANCELED: Dr. Axel Lindner, Deutsches Elektronen-Synchrotron (DESY)
We hereby would like to inform you that the colloquium on November 7th, 2023 has been cancelled due to an important commitment of the speaker Alex Lindner. He has been invited to a podium discussion with streaming on youtube on 7 November 19:00 h https://www.desy.de/aktuelles/oeffentliche_abendvortraege/hamburg/index_ger.html Feel free to attend it if you would like (link can be found on the above web page). We are working towards getting Alex Lindner to Mainz in the SoSe 2024.
16:15 Uhr s.t., HS KPH

14.11.23Prof. Yoichiro Tanaka, Tohoku University, Japan
The digital world is producing nearly a hundred Zetta bytes of data per year and creating values for the quality of society. A huge amount of data is being stored, processed, transmitted, and then shared via large scale networked datacenters which consist of millions of data storage systems filled with perpendicular magnetic recording (PMR) hard disk drives. The PMR technology was invented by Shunichi Iwasaki in 1975 and the first commercial product was launched in 2005. Since then, the data storage has become the ever-growing foundation of the digital world and led the data-driven innovations such as bigdata AI analytics, internet of things, medical science, and even a blackhole visualization in astronomy. This lecture will provide the essential magnetics to create innovative data storage technology of PMR and the origin of the high-density recording performance which has led current recording density growth. The storage performance stands on the stacked system foundation and the building blocks are, from the base, physics of magnetics, 3D material controls of sub-nanometer in size, magnetic and electronic device design, storage device integration, and storage system architectures together with non-volatile memories to unleash the intrinsic performance. The development of new storage devices and the system requires a multi-scale approach and a right guiding principle to establish expected functions. As an extension of PMR research, the lecture will also show the prospect of future storage technology and the system architecture from the multi-scale view of the storage system development. A new computational storage system aiming at unifying computation power on data store and brain-inspired system considerations as well as the academism-industry relations to realize those systems will also be introduced.
Slides here...
16 Uhr c.t., HS KPH

21.11.23Prof. Kenneth Long, Imperial College UK
The ‘Laser-hybrid Accelerator for Radiobiological Applications’, LhARA, is conceived as a novel, uniquely flexible facility dedicated to the study of radiobiology. The technologies that will be demonstrated in LhARA have the potential to allow particle-beam therapy to be delivered in a completely new regime, combining a variety of ion species in a single treatment fraction and exploiting ultra-high dose rates. LhARA will be a hybrid accelerator system in which laser interactions drive the creation of a large flux of protons or light ions that are captured using a plasma lens and formed into a beam. Serving the Ion Therapy Research Facility (ITRF), the laser-hybrid approach will allow the exploration of the vast “terra incognita” of the mechanisms by which the biological response is modulated by the physical characteristics of the beam. I will describe the motivation for LhARA, present the status of its development and summarise the programme upon which the LhARA consortium has embarked to drive a step-change in clinical capability.
Slides here...
16:15 Uhr s.t., HS KPH

28.11.23Prof. Eberhard Bodenschatz, MPI for Dynamics and Self-Organization, Göttingen
82 years ago, the mathematician Andrei Nikolayevich Kolmogorov postulated that a turbulent flow should have universal statistical self-similar properties. Independently, the flow researcher Ludwig Prandtl concluded similar results 4 years later. Nobel laureates Werner von Heisenberg and Carl-Friedrich von Weizsäcker and Lars Onsager each came to the same conclusion shortly thereafter. Over the years, the expected power laws have been refined, but it has not been possible to measure them at very high turbulence level necessary. Simulations of driven turbulence on the world's largest computers provide evidence of this statistical universality. These simulations are highly idealized, they live in a periodic box, and the energy is introduced globally on large scales. Experimentally, this kind of turbulent flow is not feasible. So the question is: what do experiments show? For more than 100 years, the wind tunnel has been the canonical flow regime for turbulence research. When a fluid flows through a grid at high velocity, vortices form and decay after a short time; the flow then exhibits the universal statistical properties of turbulence. Today, electronics are highly optimized and there are the smallest hotwires made with advanced nanotechnology. This also makes it possible to measure velocities on the smallest length scales. However, very high turbulence intensity is required to measure universal static properties. In the past, experiments were mainly performed with air (hence the name wind tunnel). When using air at atmospheric pressure, the wind tunnel would have to be huge in diameter to achieve extremely high turbulence intensity to test Kolmogorov like theories. This is where the Variable Density Turbulence Tunnel (VDTT) at the Max Planck Institute for Dynamics and Self-Organization comes in. Among others, I will present recent results showing that universality is found, albeit with spatially dependent logarithmic dependence of the power-law exponents.
Slides here...
16 Uhr c.t., HS KPH

05.12.23Dr. Urmi Ninad, TU Berlin
Statistical inference aims to fit observed data into a model that explains the data and is able to make predictions. However, as we are repeatedly told, ‘correlation does not imply causation’, therefore robust prediction and reasoning about underlying processes governing the data distribution cannot be done by relying on observed statistical dependences alone. Causal reasoning aims to formalise the setting under which causal, rather than merely statistical, relationships can be inferred from observed data, thereby making the learned model more indicative of the true underlying process. In the last decade, the field of causal inference has gained immense popularity in the statistics and machine learning communities to develop and utilise this framework on the one hand, and in application domains such as economics, genetics and climate to use causal algorithms to practical problems of interest on the other hand. In this talk, I will lay the foundations of causal inference, explain the various approaches to do causal inference that have emerged in the recent years, and close the talk with examples of application of the causality framework to climate science.
Slides here...
16 Uhr c.t., HS KPH

12.12.23No Colloquium, ---
(Lecture Hall is occupied)
16:15 Uhr s.t., HS KPH

19.12.23Prof. Marialuisa Aliotta, University of Edinburgh
The Laboratory for Underground Nuclear Astrophysics (LUNA), located under 1.4km of rock under the Gran Sasso Mountain in central Italy, provides an ideal location for nuclear reaction studies of astrophysical interest. Thanks to its million-fold reduction in cosmic-induced background, LUNA affords unique opportunities to push reaction measurements to the lowest accessible energies. For over 30 years, the LUNA collaboration has thus pioneered studies of nuclear burning processes (pp-chain, CNO-, NeNa- and AlMg-cycles) directly at the relevant astrophysical energies, often for the first time [1]. In some cases, these efforts have led to remarkable results, such as for example the increased age of the universe, and have translated into a better understanding of stellar nucleosynthesis and the chemical evolution of our galaxy. In my talk, I will review some of the major highlights of LUNA’s activity and present exciting new opportunities for upcoming studies of helium- and carbon-burning reactions at the recently installed 3.5MV accelerator. [1] M. Aliotta, A. Boeltzig, R. Depalo, G. Gyurky, Ann. Rev. of Nucl. Part. Sci. 72 (2022) 177-204 [2] G. Imbriani, et al. A&A 420, 625–629 (2004)
Slides here...
16:15 Uhr s.t., HS KPH

09.01.24Prof. Dr. Markus Roth, TU Darmstadt
With the recent demonstration of fusion ignition and burn and the first energy gain from controlled fusion reactions, the laser-based fusion approach has become a promising concept for fusion energy. While not supported in Germany until a few years ago, Germany has a huge potential in taking the lead on laser-fusion research, based on its excellent science and technology in optics and lasers. Focused Energy is a US/German Startup company, spin-off of the TU Darmstadt that has gathered the world experts in laser fusion in the last two years. I will review the recent results at the Lawrence Livermore National Laboratory National Ignition Facility and sketch a pathway from this groundbreaking result to a first fusion reactor prototype.
Slides here...
16:15 Uhr s.t., HS KPH

16.01.24Prof. Marco Durante, GSI Helmholtzzentrum für Schwerionenforschung GmbH
Particle therapy is a rapidly growing and potentially the most effective and precise radiotherapy technique. However, only a tiny minority of patients receive protons or heavy ions rather than X-rays these days. Physics research is needed to address a few problems that hamper its wider diffusion. The efforts are toward making particle therapy cheaper, faster, and more conformal. In this lecture we will give some examples of applications of nuclear physics to particle therapy. In particular, for reducing range uncertainty we will discuss the use of radioactive ion beams (RIBs) for simultaneous treatment and online range verification using positron emission tomography (PET) within the ERC AdG BARB (Biomedical Applications of Radioactive ion Beams) project at GSI/FAIR. We will also report on recent experiments in collaboration with Helmholtz Institute Mainz.
Slides here...
16:15 Uhr s.t., HS KPH

23.01.24CANCELED: Prof. Jonathan Wurtele, University of Berkeley, California
This talk has been canceled due to illness! The ALPHA Collaboration at CERN synthesizes, traps, and investigates the properties of antihydrogen, the antimatter equivalent of hydrogen. ALPHA’s research has the goal of testing the standard model which holds that antihydrogen and hydrogen have the same spectrum, and the prediction of general relativity that antihydrogen atoms experience the same gravitational force as hydrogen atoms do. ALPHA’s experiments conducted over the last decade produced measurements of the 1S-2S line, hyperfine structure, Lyman-alpha transition, and charge neutrality of antihydrogen. This presentation will predominantly delve into our latest breakthrough. Utilizing an innovative magnet system, we have successfully observed, for the first time, the interaction of neutral antimatter with the Earth’s gravitational field. The best fit to our measurements yields a value of (0.75 ± 0.13 (stat. + syst.) ± 0.16 (simulation)) g for the local acceleration of antimatter towards the Earth, consistent with the predictions of general relativity. We rule out the possibility of antihydrogen experiencing an upwards acceleration g in the Earth’s gravity. Finally, potential paths to higher-precision gravity experiments will be discussed.
16:15 Uhr s.t., HS KPH

30.01.24Prof. Silvia Masciocchi, Heidelberg/GSI
Very high energy densities are reached in ultra-relativistic collisions of heavy ions. Under these conditions, the confinement in strongly-interacting matter is lifted, and a quark-gluon plasma (QGP) is formed. At the highest temperatures realized in the laboratory, this system offers us the opportunity to study QCD matter under extreme conditions. The successful heavy-ion program at the LHC provides data of increasing precision. I will illustrate how experimental evidence supports the description of the QGP by fluid dynamics. This has been recently extended to include even rare and penetrating probes such as heavy quarks. Through this description and making use of neural networks and Bayesian inference, we are able to determine fundamental properties of QCD with increasing precision. A quick look into the formidable detectors with which we gain this evidence in the ALICE will complete the overview.
Slides here...
16:15 Uhr s.t., HS KPH

06.02.24Prof. J.C. Seamus Davis, University of Oxford
Everything around us, everything each of us has ever experienced, and virtually everything underpinning our technological society and economy is governed by quantum mechanics. Yet this most fundamental physical theory of nature often feels as if it is a set of somewhat eerie and counterintuitive ideas of no direct relevance to our lives. Why is this? One reason is that we cannot perceive the strangeness (and astonishing beauty) of the quantum mechanical phenomena all around us by using our own senses. I will describe the history of development of techniques that allow us to visualize electronic quantum phenomena and new states of quantum matter directly at the atomic scale. As recent examples, we will visually explore the previously unseen and very beautiful forms of quantum matter making up electronic liquid crystals[1,2], high temperature superconductors[2,3,4] and electron-pair crystals[5,6,7,8]. I will discuss the implications for fundamental physics research and also for advanced materials and new technologies, arising from quantum matter visualization. References: 1. Science 344, 612 (2014) 2. Nature 570, 484 (2019) 3. Science 357, 75 (2017) 4. Science 364, 976 (2019) 5. Nature 571, 234 (2020) 6. Nature 532, 343 (2016) 7. Science 372, 1447 (2021) 8. Nature 618, 921 (2023)
Slides here...
16:15 Uhr s.t., HS KPH

Koordination:

Prof. Dr. Sonia Bacca
JGU Mainz, Institut of Physics
Excellence Cluster PRISMA+
s.bacca@uni-mainz.de

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