YRC Dinner Seminar: Is Schwinger-Keldysh (stochastic) hydrodynamics compatible with thermodynamic equilibrium?
Institut für Theoretische Physik, Phil 16, SR
Hydrodynamics provides a universal, long-wavelength, low-energy effective description of many-body systems close to thermal equilibrium. A strong guiding principle in developing hydrodynamic models is Âhydrostatic compatibility  the requirement that, when a system relaxes back to equilibrium, the predictions of hydrodynamics should align with those of conventional thermodynamics or statistical field theory. In recent years, a more robust "effective field theory" framework for hydrodynamics has emerged, known as Schwinger-Keldysh hydrodynamics, which systematically describes hydrodynamics together with stochastic thermal fluctuations starting from a symmetry-based effective action principle. In this talk, we will briefly review this fascinating new framework and explore how it measures against the principle of hydrostatic compatibility
Tuesday, 8 July 2025
11:15
Seminar Theoretische Quantendynamik
Dr. Sergey Volkov, MPIK
Two-loop vacuum polarization in the Coulomb field of a nucleus
Seminar room 242, Bothe Lab
16:30
Heidelberg Joint Astronomical Colloquium
Stephen Smartt
Compact star mergers, kilonovae and r-process element production
Two binary neutron star mergers have been detected from their gravitational wave signature. The first, in 2017 had an electromagnetic counterpart comprising a high energy and radio emission and a thermal component called a kilonova powered by radioactive heavy elements. The composition of the ejecta, mostly elements heavier than iron is still debated. Nucleosynthesis and atomic data arguments suggest a number of 1st and 2nd process elements have detected spectral signatures. The was no counterpart from the second binary neutron star merger in 2019 and no further merger has been detected by LIGO-Virgo-Kagra since. However, surprisingly two long gamma ray bursts have shown convincing signatures of an infra-red excess powered by heavy element decay, and the luminosity can be modelled with kilonova thermal emission. I will present the data, current debates on the chemical element signatures in the spectrum, discuss the relatively low rate of discovery and the put the two long GRB discoveries into context. To arrange a visit with the speaker during the visit, please contact their host: Fabian Schneider
17:00
Particle Colloquium
Prof. Dr. Pamela Ferrari
Highlights of the HL-LHC physics projections by ATLAS and CMS
Physikalisches Institut INF 226, Konferenzraum 1-3 (Room 00.101 bis 00.103)
Wednesday, 9 July 2025
09:30
Seminar Dynamik und Struktur von Atomen und Molekülen
Tobias Schmitt & Romain Dubroeucq
Dual Comb Spectroscopy for Atmospheric Greenhouse Gas Measurements in Heidelberg
Zentraler Seminarraum / Central seminar room (library)
17:00
Zentrum für Quantendynamik Kolloquium
Prof. Sylvain Nascimbene
Exploring quantum Hall physics with ultracold dysprosium atoms\n
Physikalisches Institut, INF 226, K 1-3
Exploring quantum Hall physics with ultracold dysprosium atoms Prof. Sylvain Nascimbène Laboratoire Kastler Brossel, Collège de France, Paris Ultracold atomic gases offer a versatile platform for exploring rich phenomena in quantum matter. In particular, topological states akin to those found in the quantum Hall effect can be engineered by simulating orbital magnetic fieldsÂan approach greatly facilitated by the use of synthetic dimensions. In this talk, I will present our experimental realization of a quantum Hall system using ultracold gases of dysprosium atoms. By leveraging the atomÂs large internal spin (J=8), we encode a synthetic dimension and couple it to atomic motion via two-photon optical transitions, which generates an effective magnetic field. We observe hallmark signatures of quantum Hall physics, including a quantized Hall response and gapless, chiral edge modes. I will then describe a more intricate experiment designed to probe spatial entanglement by simulating the so-called entanglement Hamiltonian. Using the Bisognano-Wichmann theoremÂwhich relates the entanglement Hamiltonian to a spatially deformed version of the original systemÂwe implement this deformation along the synthetic dimension. Lastly, I will discuss our recent investigation into a topological phase transition, induced by introducing an additional lattice potential. I will highlight the systemÂs behavior in the critical regime and explore the emergent features associated with the transition.
Thursday, 10 July 2025
11:00
Teekolloquium
Professor Ulrich Uwer, Professor Vincenzo Vagnoni
Precision Physics at a Hadron Collider: Highlights from the LHCb-Experiment
Grosser Hoersaal/Big Lecture Hall (library)
Since the start of the Large Hadron Collider (LHC) the LHCb experiment
has become the leading flavour physics experiment worldwide. Initially
designed to probe the matter-antimatter asymmetry of the universe by
precision measurements of CP violation in heavy flavour decays, it
continuously expanded its physics portfolio to cover also QCD and
electroweak physics, the study of heavy ion collisions and most recently
also fixed target physics. The kolloquium will start with a presentation
of highlights from flavour- and electroweak physics, the second part
will focus on strong interactions and new exotic states found by
the experiment.
11:15
ARI Institute Colloquium
Kai Wu
From Debris Disks to Million-Body Clusters: Planetary Perturbations, Stellar Interactions, and DRAGON-III's First Insights
ARI, Moenchhofstrasse 12-14, Seminarraum 1.OG
This talk has two topics. The first part is about planetary systems in star clusters. Several tens of planetary systems, including our Solar System, contain both planets and debris structures. Most stars are believed to be born in clustered environments, such as in star clusters. In such environments, debris discs evolve through interactions with stellar neighbours and planets. I use gravitational N-body simulations to investigate how the joint effect of star cluster environments and planets affects the dynamical evolution and stability of debris discs. I focus on how (i) the presence of a planet, (ii) the density of the star cluster, and (iii) the orbit of host stars within the cluster affect the stability and evolution of debris discs, as well as the characteristics of escaping particles and remaining discs. The second part of my talk is about globular clusters. They are abundant in galactic disks and spheroids, serve as ideal laboratories for studying stellar evolution alongside Newtonian and relativistic dynamics. The previous study of Dragon-II (Arca Sedda et al. 2023) successfully revealed astrophysical details of these dynamical systems, including gravitational wave signals from compact object mergers that would be measured by LIGO/Virgo/KAGRA. As a continuation of DRAGON-II, I present the DRAGON-III project and report on its preliminary results, which focuses on the simulations of million-body globular clusters and million-body nuclear clusters over 10 Gyr.
Friday, 11 July 2025
17:00
Physikalisches Kolloquium
Prof. Dr. Stefan Filipp
Advancing Quantum Information Processing with Superconducting Circuits
KIP, INF 227, Hörsaal 1
Quantum computers have the potential to solve complex problems efficiently. However, to unleash their full potential, complex quantum systems have to be manufactured, manipulated and measured with unprecedented accuracy and precision. In this presentation I will focus on superconducting qubits as one of the most promising platforms for quantum computing. I will illustrate the building blocks of a quantum processor using a system based on 17 transmon-type qubits, which we are currently operating in our laboratory. In this architecture tunable coupling elements are harnessed to generate multi-qubit operations between two or more qubits and to efficiently create many-body entanglement. Moreover, I will address alternative superconducting qubits with improved protection against environmental influences.
Tuesday, 15 July 2025
11:15
Seminar Theoretische Quantendynamik
Ingmar Kloß, MPIK
Geometrical reconstruction of Dirac solutions: gravitational interactions and comparison to electromagnetic case
Seminar room 242, Bothe Lab
14:15
Kosmologie und Elementarteilchenphysik
Mariateresa Crosta
TBA
Institut für Theoretische Physik, Online
TBA
16:30
Heidelberg Joint Astronomical Colloquium
Pablo Marchant
From mass transfer to stripped stars
Binary interactions shape the evolution of the most massive stars, leading to significant deviations from the evolutionary pathways possible in single star evolution. These processes impact the universe at large scales and result in high energy events such as peculiar supernovae and gravitational wave sources. To understand these outcomes, it is important to assess binary evolution in early stages ranging from pre-interaction, roche-lobe overflow and post-interaction phases. I will discuss the current progress in our understanding of mass-transferring binaries, covering the impact of this process on the donor star (with the possible production of a stripped star), as well as the response of its companion. Of particular importance in recent years is the identification of bloated stripped stars caught immediately after interaction which provides a snapshot of the end-states of mass transfer, and I will discuss how their properties constrain orbital evolution and the efficiency of mass transfer. I will also emphasize that many of the uncertain processes in massive binary star evolution can also be assessed through the study of intermediate mass systems, for which the physics in early evolutionary phases does not differ significantly. To arrange a visit with the speaker during the visit, please contact their host: Jaime Villaseñor (MPIA)
17:00
Particle Colloquium
Prof. Dr. Ulrich Uwer
The LHCb Phase-2b upgrade
Physikalisches Institut INF 226, Konferenzraum 1-3 (Room 00.101 bis 00.103)
Wednesday, 16 July 2025
17:00
SFB1225 ISOQUANT
Prof. Dr. Frauke Gräter
Meet&Mingle@ISOQUANT: Networking and Mentoring platform for FLINTA* students in physics
Institut für Theoretische Physik, PI, Goldene Box
tba
Thursday, 17 July 2025
11:15
Teekolloquium
Prof. Wim Ubachs
Molecular hydrogen at the heart of physics
Grosser Hoersaal/Big Lecture Hall (library)
Hydrogen in atomic and molecular form, including the deuterium and tritium isotopes, is key in astrophysics, as well as in stellar and man-made fusion. Hydrogen has become a benchmark system for testing theory at the most fundamental level and for probing physics beyond the Standard Model: are there forces beyond the three included in the Standard Model of physics plus gravity, and are there just 3+1 dimensions. Comparison of laboratory wavelengths of transitions in hydrogen may be compared with the lines observed during the epoch of the early Universe to verify whether fundamental constants of Nature have varied over cosmological time. In recent studies dissociation limits of H2, HD and D2 are measured to 10-digit accuracy. Currently vibrational transitions are being measured via sensitive cavity-enhanced techniques, also for the radio-active HT molecule. In H2 record-high sensitivity is achieved for probing a quadrupole transition in saturation.
ARI Institute Colloquium
Anna Saburova
On the enigmatic beasts - giant low surface brightness galaxies
ARI, Moenchhofstrasse 12-14, Seminarraum 1.OG
Giant low surface brightness galaxies (gLSBGs) have the largest discs in the Universe with the radii up to 130 kpc. The formation of such enormous discs is a stress-test for the hierarchical galaxy formation paradigm and without clarifying it we cannot paint a coherent picture of galaxy evolution. In the talk I will give the answers to the following questions. How rare are gLSBGs? What are the formation scenarios of gLSBGs? And how does it all correspond to the results of modern cosmological simulations? These answers are based on both in-depth study of 8 gLSBGs, including the results of our deep spectroscopic and photometric observations, HI data collected in the framework of our observing programs and complemented by archival datasets. Finally, we used deep optical images from HSC Subaru Strategic Program and publicly available redshift catalogs, estimated the volume density of gLSBGs in the local Universe and compared it to state-of- the-art numerical simulations.
16:15
Teilchen-Tee
Clare Burrage
TBA
Institut für Theoretische Physik, Phil12, SR106
TB
Friday, 18 July 2025
17:00
Physikalisches Kolloquium
Prof. Ralph Keeling
Perspectives on modern climate change from 67 years of direct atmospheric measurements
Perspectives on modern climate change from 67 years of direct atmospheric measurements Prof. Ralph Keeling GEOSCIENCES RESEARCH DIV., Scripps Institution of Oceanography, UC San Diego At the forefront of modern climate change research are time-series observations of atmospheric CO? and related species, such as atmospheric O?. These records now span many decades, providing unequivocal evidence of the profound influence of humans on the planetÂparticularly through the burning of fossil fuels. This talk will chart the history of this field, from the early measurements and scientific puzzles to the ongoing challenges of mitigating and adapting to climate change.
