Driven by the increasingly complete observational knowledge of systems of satellite galaxies, mutual spatial alignments and relations in velocities among satellites belonging to a common host have become a productive field of research. The Planes of Satellite Galaxies issue is maybe the best-known type of such phase-space correlations. There is an ongoing, controversial debate on how much of a challenge observed, flattened distributions of apparently co-orbiting satellite galaxies pose for the ?CDM model of cosmology. With the fast expansion of proper motion measurements in recent years, largely driven by Gaia, other peculiar phase-space correlations have been uncovered among the satellites of the Milky Way. Concurrently, more complete observational samples of satellite galaxies around more distant hosts now enable us to expand the study such correlations to the Andromeda galaxy, Centaurus A, and beyond. In my talk, I will provide an introduction to this highly active field of research. I will review some of our recent results concerning planes of satellite galaxies, lopsided satellite galaxy systems, a potential Âtoo-many-satellites problem, and talk about how these (dis-)agree with cosmological expectations and other suggested formation scenarios.
16:15
Teilchen-Tee
Giuliano Giacalone
Imaging atomic nuclei at high-energy colliders: a new window onto the strong nuclear force (Pre-talk 15:30)
Institut für Theoretische Physik, Phil12, SR106
Recent experimental results obtained at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) indicate that multi-particle correlation measurements in the soft sector of heavy-ion collisions probe the details of the spatial distributions of nucleons in the colliding ions. These findings have lead to remarkable advances in matching notions from low-energy nuclear physics to hydrodynamic simulations of heavy-ion collisions, which I shall discuss in this talk. I show that nuclear structure theory is today an integral part of the hydrodynamic framework of heavy-ion collisions, and that issues opened by collider data have improved the state-of-the-art of this area in several directions. I argue that this has opened a new direction in nuclear physics research, and highlight prospects and benefits from future studies (both theoretical and experimental) connecting effective descriptions of QCD matter across different energy scales.
Friday, 17 May 2024
17:00
Physikalisches Kolloquium
Prof. Dr. Peter Hommelhoff
Particle accelerator on a nanophotonic chip
KIP, INF 227, Hörsaal 1
Particle accelerators are ubiquitous tools across scientific, industrial, and medical domains, pivotal not only in advancing particle physics but also in applications such as sterilization and radiotherapy in modern healthcare facilities. Traditionally, these accelerators harness microwave fields to impart momentum to swift electrons or other charged particles. Our research explores a paradigm shift, demonstrating the feasibility of employing laser light to achieve electron acceleration. Crucially, this approach necessitates structures capable of generating accelerating fields at the scale of the driving laser's wavelength  a scale substantially smaller than conventional accelerators, on the order of microns. Leveraging advancements in nanofabrication, we have developed the nanophotonic counterpart of an accelerator, enabling the acceleration of electrons through purely optical forces. A milestone achievement has been the realization of the electron "bucket," effectively confining and accelerating electrons within a 220nm narrow, 500 micron long accelerator channel. In our experiments, we have demonstrated electron acceleration from 28 keV to over 40 keV, marking significant progress towards compact and efficient light-driven electron devices. Furthermore, we explore intriguing phenomena arising from the natural bunching of electrons on attosecond timescales and the ability to shape individual electron wavepackets. These capabilities open new vistas for electron imaging, particularly in the realm of quantum mechanical phase imaging. In this presentation, we provide an overview of our experimental progress, offering insights into the potential of light-driven electron accelerator devices and electron wavepacket shaping and coupling.
Tuesday, 21 May 2024
14:15
Kosmologie und Elementarteilchenphysik
Luca Amendola
Improving precision and accuracy in cosmology
Institut für Theoretische Physik, Phil19
A new and promising avenue was recently developed for analyzing large-scale structure data with a model-independent approach, in which the linear power spectrum shape is parametrized with a large number of freely varying wavebands rather than by assuming specific cosmological models. Here we show, using a Fisher matrix approach, that precision of this method for the case of the one-loop power spectrum is greatly improved with the inclusion of the tree-level bispectrum. We also show that accuracy can be similarly improved by employing perturbation theory kernels whose structure is entirely determined by symmetries instead of evolution equations valid in particular models (like in the usual Einstein-de Sitter approximation).
16:30
Particle and Astroparticle Theory Seminar
Dr. Xin Wang (Univ. of Southampton, UK)
A short review on modular flavor symmetries
Seminar room Lindner 339, Gentner lab, 2nd floor
It has recently been demonstrated that the modular symmetry offers an elegant solution to the longstanding flavor mixing puzzle This innovative approach considers neutrino masses as modular forms, dependent on a complex modulus parameter. In this talk, I will briefly review recent developments in modular flavor symmetries, including their theoretical motivations, the basic knowledge about modular transformations, the generic methodology to construct a modular-invariant flavor model, and the distinctions between modular flavor symmetries and traditional flavor symmetries. In addition, I will also talk about the modulus stabilization.
Heidelberg Joint Astronomical Colloquium
Professor James Drake
Interchange magnetic reconnection as the driver of the fast solar wind
Philosophenweg 12, Main Lecture hall (gHS)
The mechanism that drives the solar wind has been a topic of extensive scientific debate since the 1960's when the existence of the solar wind was confirmed with spacecraft observations. In its recent closest approaches to the sun the Parker Solar Probe (PSP) spacecraft is revealing wind structure not seen by spacecraft at 1AU. The bursty radial flows and associated local reversals of the radial magnetic field (switchbacks) exhibit a spatial periodicity that is linked to that of network magnetic field near the solar surface (Bale et al. 2021; ApJ 923,174). The observations point to magnetic reconnection between open and closed magnetic flux in coronal holes (interchange reconnection) as the driver of these bursts. The corresponding enhancements in plasma pressure, wind speed, and energetic ions further suggest that interchange reconnection is the fundamental source of energy that drives the fast solar wind. We use the PSP data along with the basic characteristics of reconnection to deduce the local properties of interchange reconnection near the solar surface, including the characteristic strength of the reconnecting magnetic, the ambient density, the rate of reconnection and associated rate of energy release (Bale et al. 2023; Nature, vol. 628). An important conclusion of the analysis is that coronal interchange reconnection is in the collisionless regime and that the energy released by interchange reconnection is sufficient to drive the wind. Analytical estimates are supported by particle-in-cell simulations of interchange reconnection that establish that the structure of reconnection exhausts match PSP measurements. The spectra of energetic protons and alpha particles from the simulations, which take the form of powerlaws at high energy, also match the observations by the PSP. The bursty nature of interchange reconnection has implications for the development of the measured turbulence in the solar wind, which is currently being explored. These results have significant implications for understanding the winds produced by objects throughout the universe. Those unable to attend the colloquium in person are invited to participate online through Zoom (Meeting ID: 942 0262 2849, passcode 792771) using the link: https://eu02web.zoom-x.de/j/94202622849?pwd=dGlPQXBiUytzY1M2UE5oUDRhbzNOZz09 During his visit to Heidelberg, Professor Drake will be available for meetings by arrangement with his host, Brian Reville (brian.reville@mpi-hd.mpg.de)
17:00
Particle Colloquium
Aishik Ghosh
Simulation-Basted Inference Techniques and its....
Physikalisches Institut INF 226, Konferenzraum 1-3 (Room 00.101 bis 00.103)
Wednesday, 22 May 2024
09:30
Seminar Dynamik und Struktur von Atomen und Molekülen
Hannes Lindenblatt, Ionizing atoms & molecules in strong fields
Charge transfer in small Xenon-clusters
Central Seminar Room, library building
11:15
Bothe-Kolloquium
Prof. Simon Stellmer, Universität Bonn
Isotope shift spectroscopy
Central seminar room, library building
The search for "new" particles is dominated by the quest for dark matter candidates, but there are also motivations to search for yet undiscovered particles not related to dark matter. In particular, a growing community is searching for a hypothetical New Boson that would couple neutrons and electrons. Such an interaction would show up as an additional contribution to the binding energy of an electron in an atom, and can be accessed directly through the isotope shift of carefully chosen optical transitions. While this field of research has flourished in the past few years, it seems that we are re-discovering nuclear physics rather than new particles. I will give an overview on the current status of the field, particularly on the elements calcium, zinc, and mercury.
16:30
Zentrum für Quantendynamik Kolloquium
Prof. Dr. Herwig Ott
Dissipation in Bose-Einstein Condensates
Thursday, 23 May 2024
11:15
ARI Institute Colloquium
Ulrich A. Glasmacher
50 Years of Plate Tectonic - Thats all?
ARI, Moenchhofstrasse 12-14, Seminarraum 1.OG
ÂPlate tectonics is a young field of geoscientific research. What are the questions driving geoscientific research today? Can geoscience develop a unification theory of the endogen and exogen processes on our planet Earth that may even be valid for the processes on other planets? The lecture provides an insight into the development of geoscientific research over the last 500 years. It ends in a detailed explanation of today's research on plate tectonics. Surprises, better changed ways of thinking, are planned. Let me take you on a journey through the last 500 years and take you into the depths of our planet Earth and its effects on the surface evolution of the planet.
16:15
Particle and Astroparticle Theory Seminar
Dr. Florian Goertz (MPIK)
Tba.
ITP Heidelberg, Room 106, Philosophenweg 12
Joint Seminar with ITP Heidelberg, Teilchentee.
Teilchen-Tee
Florian Goertz
TBA (Pre-talk 15:30)
Institut für Theoretische Physik, Phil12, SR106
TBA
Friday, 24 May 2024
17:00
Physikalisches Kolloquium
Prof. Dr. Johannes Quaas
The role of aerosol - cloud interactions as driver of climate change in the past and in the future
KIP, INF 227, Hörsaal 1
Particles in the atmosphere - aerosols - may serve as cloud condensation nuclei. Increases in aerosol concentrations thus change cloud droplet concentrations and thus enhance the brightness of clouds. Such aerosol-cloud interactions exert a cooling effect on climate. The presentation will explain how we learned to quantify this climate forcing from climate models and satellite observations. It will detail where open questions are, and what implications small or large aerosol-cloud effects have on climate sensitivity as well as past and future climate change. The improvement of air quality implies reduced aerosol forcing and thus enhanced warming currently and in the future, but also climate intervention by artificially enhancing the cloud brightness is in discussion.
Monday, 27 May 2024
16:30
Particle and Astroparticle Theory Seminar
Dr. Peter Matak (Comenius University, Bratislava)
Diagrammar for Leptogenesis
Seminar room Lindner 339, Gentner lab, 2nd floor
The CP asymmetries necessary for explaining the observed baryon asymmetry of the universe require irreducible complex phases in couplings and imaginary kinematics from loop diagrams. The two conditions still do not guarantee a nonvanishing source term of an asymmetry in the Boltzmann equation, as it may vanish due to the unitarity and CPT symmetry constraints. After a brief introduction to holomorphic cutting rules suitable for tracking these cancellations, we discuss the possibility of generating sufficient asymmetry in the Dirac leptogenesis scenario. The model introduced in arXiv:2404.16934 contains only massless particles and combines the right-handed neutrino freeze-in and the lepton-number asymmetry wash-in. Finally, possible generalization of the CPT and unitarity constraints to thermally corrected asymmetries will be discussed.
Tuesday, 28 May 2024
14:15
Kosmologie und Elementarteilchenphysik
Robert Brandenberger
Searching for Cosmic Strings in New Observational Windows
Institut für Theoretische Physik, Phil19, SR
TBA
16:30
Heidelberg Joint Astronomical Colloquium
Professor Alexander Heger
Title to be announced
Philosophenweg 12, Main Lecture hall (gHS)
Abstract to be announced. Those unable to attend the colloquium in person are invited to participate online through Zoom (Meeting ID: 942 0262 2849, passcode 792771) using the link: https://eu02web.zoom-x.de/j/94202622849?pwd=dGlPQXBiUytzY1M2UE5oUDRhbzNOZz09 During his visit to Heidelberg, Professor Heger will be available for meetings by arrangement with his hosts, Friedrich Roepke (friedrich.roepke@h-its.org) and Andreas Sander (andreas.sander@uni-heidelberg.de)
Wednesday, 29 May 2024
09:30
Seminar Dynamik und Struktur von Atomen und Molekülen
Rui Jin; Excited atoms & molecules in strong laser fields
Fraunhofer-type transmission spectroscopy of CF4 molecules in intense x-ray fields
Zentraler Seminarraum / Central seminar room (library)
10:00
Zentrum für Quantendynamik Kolloquium
Prof. Stephanie Reimann
tba
EINC, INF 227, Seminarraum 1
15:00
Seminar Stored and Cooled Ions
Jost Herkenhoff, MPIK
Towards sympathetic cooling of particles using electron cyclotron radiation at the ELCOTRAP experiment
Hybrid seminar: central seminar room, library building + Zoom: Meeting-ID: 915 1204 2752 Passcode: 758933
