Asymptotic safety can render quantum field theories ultraviolet complete and predictive. There is good evidence that quantum gravity may be asymptotically safe. After presenting the main idea and reviewing some of the evidence for it, I will focus on scalar-tensor theories and discuss results on asymptotically safe scalar-tensor theories from the perspective of Horndeski gravity. In particular, I will explain how the predictive power of asymptotic safety constrains terms in a Horndeski Lagrangian and how asymptotic safety could serve as a theoretical selection principle for dynamical dark energy models, both in and beyond Horndeski.
16:30
Heidelberg Joint Astronomical Colloquium
Anna de Graaff
A new view of the red and distant Universe from JWST/NIRSpec
In its three years of science operations, JWST has revolutionized our understanding of the early Universe. Arguably the most impressive leap forward has come from the NIRSpec instrument, providing a detailed view of the physical processes  star formation, feedback, and the growth of massive black holes  that shaped the faintest, reddest, and most distant galaxies. Among a wealth of discoveries, one overarching surprise has emerged: galaxies in the early Universe formed and matured extremely fast. Massive galaxies with old stellar populations exist already in the first billion years of the Universe, with some showing morphologies reminiscent of our own Milky Way, while others host unexpectedly massive black holes. The potential implications on galaxy formation models are profound, as current models struggle to reproduce such rapid galaxy assembly. I will present an overview of key extragalactic surveys from JWST/NIRSpec, focusing on the major discoveries that they have enabled and the challenges that remain.
Wednesday, 11 June 2025
09:30
Seminar Dynamik und Struktur von Atomen und Molekülen
Carlo Kleine; Excited atoms & molecules in strong fields
Intensity Dependencies in Nonlinear Frequency Upconversion and Bright Nonclassical Light
Zentraler Seminarraum / Central seminar room (library)
11:15
Bothe-Kolloquium
Dr. Lukas Bruder; Universität Freiburg
Pushing nonlinear spectroscopy and coherent control towards highly dilute samples and the extreme ultraviolet spectral domain
Central seminar room, library building
We develop nonlinear spectroscopy and coherent control techniques in the gas phase at visible wavelengths and push boundaries towards applications in the extreme ultraviolet (XUV) spectral domain. In the first part of my talk, I will report about high-resolution two-dimensional spectroscopy in the gas phase to study the structure and ultrafast dynamics of molecular nanosystems isolated from environmental perturbations. The nanosystems consist of atomic clusters doped with individual molecules which provide handy systems to explore solute-solvent interactions and effects of nano confinement. In the second part of my talk, I will introduce our methods for coherent manipulation of XUV pulses and discuss applications. We use phase-modulated XUV pulses for Fourier transform spectroscopy and spectral phase shaping to control strong-field processes.
14:15
Kosmologie und Elementarteilchenphysik
Laura Herold
TBA
Institut für Theoretische Physik, Online; Note unusual date (Tunch schedule)
TBA
15:30
Seminar Stored and Cooled Ions
Dr. Tim Lellinger, CERN/MPIK
First laser-spectroscopy measurements across N = 32 in the calcium isotopic chain at the COLLAPS setup at ISOLDE/CERN
Hybrid seminar: central seminar room, library building + Zoom: Meeting-ID: 915 1204 2752 Passcode: 758933
PLEASE NOTE THE UNUSUAL TIME!
16:30
Zentrum für Quantendynamik Kolloquium
Dr. Sylvain Ravets
Synthetic Polariton Matter: Hamiltonian Tomography and Optical Nonlinearities
Dr. David Lucas, University of Oxford, Department of Physics
Quantum networking and computing with trapped ions
Grosser Hoersaal/Big Lecture Hall (library)
ARI Institute Colloquium
Geraint Lewis
Confronting the Cosmological Principle: How secure are the foundations of the cosmos?
ARI, Moenchhofstrasse 12-14, Seminarraum 1.OG
I will present our recent work using quasars and radio galaxies to challenge the cosmological principle  the foundation of modern cosmology. This principle asserts that the universe is isotropic and homogeneous, yet the Cosmic Microwave Background (CMB) reveals a strong dipole, attributed to our motion relative to the local Hubble flow. This motion should be imprinted on other observables, and I identify a dipole in large-scale surveys of cosmological sources. Whilst there is general agreement in the dipole direction, the amplitude remains at odds with expectations from the CMB. I will explore possible explanations for these tensions and consider whether a fundamental shift in our cosmological understanding is on the horizon.
16:15
Teilchen-Tee
Aqeel Ahmed
Primordial Leptogenesis
Institut für Theoretische Physik, Phil12, SR106
In this talk, I will present a framework that provides a mechanism to generate the baryon asymmetry of the universe through inflationary dynamics. I will introduce a minimal model where lepton and baryon asymmetries are generated during a reheating phase through the asymmetric decay of the inflaton field into SM Higgs bosons. This primordial lepton asymmetry is then converted to the baryon asymmetry through the electroweak sphaleron processes. Our mechanism offers an elegant UV completion of Dirac Leptogenesis.
Friday, 13 June 2025
17:00
Physikalisches Kolloquium
Prof. Dr. Erwin Frey
Emergence and Self-Organisation in Biological Systems
KIP, INF 227, Hörsaal 1
Isolated systems tend to evolve towards thermal equilibrium, a special state that has been a research focus in physics for more than a century. By contrast, most processes studied in living and life-like systems are driven and far from thermal equilibrium. A fundamental overarching hallmark of all these processes is the emergence of structure, order, and information, and we are facing the major challenge of identifying the underlying physical principles. Two exciting problems are the self-organised formation of spatio-temporal patterns and the robust self-assembly of complex structures. In both fields, there have been recent advances in understanding the underlying physics that will be reviewed in this talk.
Tuesday, 17 June 2025
14:15
Kosmologie und Elementarteilchenphysik
Emille E. O. Ishida
TBA
Institut für Theoretische Physik, Online
TBA
16:30
Heidelberg Joint Astronomical Colloquium
Jennifer Schober
The magnetic history of the Universe
Magnetic fields permeate nearly every astrophysical environment, from planets and stars to galaxies and galaxy clusters. In these cosmologically overdense regions, magnetic fields are thought to arise primarily from magnetohydrodynamic (MHD) dynamos. These mechanisms convert turbulent kinetic energy into magnetic energy through the stretching and twisting of field lines. In the first part of this talk, I will present recent advances in our understanding of MHD dynamos. In the second part, I will focus on the vast underdense regions of space, cosmic voids, where blazar observations have revealed the existence of magnetic fields. As voids lack turbulence and therefore the energy source of classical dynamos, these large-scale magnetic fields likely originate in the very early Universe shortly after the Big Bang and therefore offer a unique window into fundamental physics. I will outline key theoretical models of magnetogenesis and present new insights in the pre-recombination evolution of these primordial magnetic fields from state-of-the-art numerical simulations. To arrange a visit with the speaker during the visit, please contact their host: Philipp Girichidis
Wednesday, 18 June 2025
09:30
Seminar Dynamik und Struktur von Atomen und Molekülen
Jan-Hendrik Oelmann; Highly charged ion dynamics
tba
Central Seminar Room, library building
15:00
Special Seminar
Dr. Laura Dreissen, Vrije Universiteit Amsterdam
Precision quantum metrology in trapped ions for tests of fundamental physics
Zentraler Seminarraum / Central seminar room (library)
Abstract:
The Standard Model (SM) of particle physics describes fundamental interactions between the known particles extremely well, but it fails to provide answers for big open questions, e.g. the origin and composition of dark matter or the matter anti-matter asymmetry. Hunting for new physics effects with small cross sections, whether through broken symmetries, new feeble interactions or heavy particles at energies beyond our current reach, requires a high sensitivity. In this talk I will elaborate on how precision quantum metrology in trapped cold ions can be used for competitive tests of the SM and search for new physics [1]. In particular, I will show how isotope shift measurements in trapped ions can be used as a sensitive probe for a possible new boson-mediated fifth force that couple electrons and neutrons [2]. Our latest results in Yb+ ions [4] were used to benchmark ab-initio nuclear theory and put competitive bounds on a new long-range boson. To further push this field forward, my research focusses on novel techniques involving quantum state engineering. With entangled states in Ba+ I aim to become more robust against ambient noise and systematic effects, hereby improving the measurement sensitivity. I will apply these techniques to further explore isotope shift spectroscopy, improve optical clock spectroscopy and investigate atomic parity violation. In this talk, I will give a general overview of my line of research and report on the experimental progress.
[1] M. Safronova et al., Rev. Mod. Phys. 90, 025008 (2018)
[2] J. C. Berengut et al., 413 Phys. Rev. Lett. 120, 091801 (2018)
[3] M. Door et al., Phys. Rev. Lett 134, 063002 (2025).
16:15
Teilchen-Tee
Stella Tallulah Schindler
TBA
Institut für Theoretische Physik, Phil12, SR106
TBA
Monday, 23 June 2025
10:00
How to MPIK
Lobby area, Library
International Office/Administration
We will answer all kinds of questions about the daily work routine at MPIK. The event is of course intended for new employees, internationals, but also for old employees who have to deal with certain problems with the administration in Germany or at MPIK.
