Time, Place:

11:15 ,Otto Hahn lecture hall, library building

Speaker:

Prof. Dr. Andrey Surzhykov, Physikalisch-Technische Bundesanstalt and Technische Universität Braunschweig

Title:

Elastic photons scattering by atoms: From low-energy resonances to electron-positron pair production

Abstract: One of the fundamental processes of light-matter interaction is elastic scattering of photons by atoms and ions. Three main channels contribute to this process, namely scattering by bound electrons, a nucleus and quantum fluctuations of the vacuum. In my presentation, I will review recent experimental and theoretical investigations of these scattering channels. In particular, I will show how the analysis of soft x-ray scattering by bound electrons can be used as an effective tool to determine the lifetimes of highly charged ions in EBIT facilities. Regarding the high energy regime, we will discuss how an accurate treatment of the interaction of electron-positron pairs with the Coulomb field of a nucleus has resolved the long-standing discrepancy between experimental and theoretical findings for the Delbrück scattering. The implications of these results for future studies of the nuclear giant dipole resonance in the MeV regime will also be briefly outlined.

Time, Place:

09:30 ,Central Seminar Room, library building

Speaker:

Cristian Medina, Ionizing atoms & molecules in strong fields

Title:

Electron capture Dynamics and Momentum Reconstruction in Ion-Neutral Collisions of Molecular Oxygen Using the Trap-REMI

Time, Place:

11:15 ,Grosser Hoersaal/Big Lecture Hall (library)

Speaker:

Prof Nirit Dudovich

Title:

Attosecond interferometry

High harmonic generation (HHG) spectroscopy has been successfully applied over the past two decades to resolve fundamental strong-field phenomena in atoms, molecules and solids. An important aspect of HHG spectroscopy lies in its coherent nature. The strong-field interaction directly transfers the coherence of the laser field into the coherent properties of the electronic wavefunction that interacts with the field, and back into the optical properties of the emitted harmonics. Resolving the internal coherence is key to reconstructing the internal dynamics, being one of the primary challenges in HHG spectroscopy. As in many other branches of physics, the presence of coherence is determined through interferometry. In this talk, I will describe advanced schemes for attosecond interferometry. The application of these schemes provides direct insights into a range of fundamental phenomena in nature - from field induced tunneling in atomic systems to subcycle dynamics in condensed matter systems.

Time, Place:

13:30 ,Zentraler Seminarraum / Central seminar room (library)

Speaker:

Prof Nirit Dudovich

Title:

Post-talk with students

for early-career researchers only (i.e. PhD students, Master students, Bachelor students, HiWis...)

Time, Place:

09:30 ,Otto-Hahn-Hörsaal, Bibliotheksgebäude

Speaker:

Prof. Dr. Klaus Blaum, MPIK

Schülerveranstaltung mit Laborführungen (+ Magnetschwebebahn), offen für alle Physik-Interessierte, Anmeldung bitte über Webseite

Time, Place:

11:15 ,Central seminar room, library building

Speaker:

Matteo Moretti, MPIK

Title:

Search for physics beyond the Standard Model with few-electron highly charged ions

Time, Place:

14:00 ,Central seminar room, library building

Speaker:

Dr Minh Phan Vo Hong - Sorbonne Université Paris

Title:

Galactic cosmic-ray transport from small to large scales

The origin of cosmic rays remains one of the greatest mysteries in Modern Astrophysics. Resolving this problem requires more insights into the transport of cosmic rays in the interstellar medium. I will discuss some progress on modelling cosmic-ray propagation from small scales, e.g. with star-forming regions or around candidate sources, to large Galactic scales. Certain probes to better constrain transport properties of cosmic rays like ionization rates, gamma-ray emissions, or local cosmic-ray spectra and anisotropies will also be discussed. The collective constraints from these probes will not only allow for improved understanding on the transport cosmic rays but might ultimately allow us to extract information about the Galactic distribution of cosmic-ray sources.

Time, Place:

09:30 ,Central Seminar Room, library building

Speaker:

Lakshmi Kozhiparambil, Highly charged ion dynamics

Title:

tba

Time, Place:

15:00 ,Hybrid seminar: central seminar room, library building + Zoom: Meeting-ID: 915 1204 2752 Passcode: 758933

Speaker:

Dr. Timo Dickel, GSI Darmstadt

Title:

New ion trapping and mass spectrometry methods for improved sensitivity and novel applications

Time, Place:

11:15 ,Central seminar room, library building

Speaker:

Maya Hager

Title:

Phasing out of Darkness: From Sterile Neutrino Dark Matter to Neutrino Masses via Time-Dependent Mixing

Time, Place:

14:00 ,Astro Physics Seminar Room

Speaker:

Dr. Stella S. Boula - INAF-Osservatorio Astronomico di Brera, Italy

Title:

Recollimation instabilities and their role in shaping MHD jets

Time, Place:

16:00 ,ITP Heidelberg University; Teilchentee, Room 106 Philosophenweg 12

Speaker:

Dr. Jeffrey Kuntz (MPIK)

Title:

Unitarity in Pseudo-Hermitian​ Quadratic Gravity

Joint Seminar with ITP Heidelberg, TeilchenteeTheories described by non-Hermitian Hamiltonians are known to possess strictly positive energy eigenvalues and exhibit unitary time evolution if their Hamiltonian possesses an anti-linear symmetry or, equivalently, is pseudo-Hermitian. We review these claims and demonstrate how quantum quadratic gravity, a theory that generally violates unitarity when viewed as a Hermitian QFT, can be complex-deformed into an anti-linear PT-symmetric theory with an action that consists of a ghost-less Hermitian free part and non-Hermitian interactions. We also show compelling evidence that the quantized theory possesses a unitary inner product and a sensible interpretation of quantum probability, thus avoiding the ghost problem present in the Hermitian formulation of quadratic gravity.