Events

Events

• Prof. Stefan Kehrein - Page curve-like behavior in quantum many-body models

  External link de

  Thursday 7 May 2026, 14:15 - 15:45 PM, Abbeanum, Straubel-HS
  
  The entanglement entropy of black holes is expected to follow the Page curve. After an initial linear increase with time the entanglement entropy reaches a maximum at the Page time and then decrease. In my talk I introduce quantum many-body models that explicitly show such a Page curve: The entanglement entropy vanishes asymptotically for late times instead of saturating at a volume law. The bending down of the Page curve is accompanied by a breakdown of the semiclassical connection between particle current and entanglement generation, a quantum phase transition in the entanglement Hamiltonian and non-analytic behavior of the q -> infinity Renyi entropy. These observations are worked out exactly in an analytically solvable model of free fermions and generalized to interacting models using numerical methods.

  Quantum Theory Seminar

• Dr. Harald Sinn - Lasing of an X-ray oscillator

  External link de

  Monday 11 May 2026, 16:15 - 18:15 PM, Abbeanum, HS 1
  
  X-ray Free-Electron Laser Oscillator (XFELO) is a concept that promises significantly higher stability and improved coherence properties compared with current free-electron lasers. The approach is based on recirculating X-ray pulses in a cavity to enable multipass amplification, analogous to optical lasers. However, achieving gain in an XFELO had so far remained elusive, largely because it requires low-loss cavity optics and exceptionally tight alignment tolerances. I will report on the first lasing of an XFELO at hard X-ray wavelengths, recently demonstrated at the European XFEL facility [1]. Lasing was achieved at 6.952 keV in a 132.8 m round-trip diamond-based Bragg cavity synchronized to the 2.23 MHz electron-bunch spacing. The presentation will focus on the X-ray optical concepts, as well as the alignment and synchronization strategies that made this result possible. The impact of non-ideal optics and heat-load-driven effects under MHz operation, will also be discussed. Finally, I will outline our strategy to further develop the method and the scientific opportunities enabled by XFELO technology.
  
  References
  [1] Rauer, P., Bahns, I., Friedrich, B. et al. Lasing of a cavity-based X-ray source. Nature (2026). https://doi.org/10.1038/s41586-025-10025-x

  PAF Colloquium

• Dr. Philip Scheiger - Kognitive Aktivierung im Physikstudium

   de

  Monday 18 May 2026, 16:15 - 18:15 PM,
  Abbeanum, HS1
  
  Kognitive Aktivierung gilt als ein zentraler Qualitätsindikator wirksamer Lehre und beschreibt Lernprozesse, in denen Studierende aktiv zur tiefgehenden Verarbeitung von Inhalten angeregt werden. Insbesondere im Physikstudium, das durch hohe Abstraktionsgrade und mathematische Formalisierung geprägt ist, entscheidet die Qualität der kognitiven Aktivierung maßgeblich über nachhaltiges Verständnis und die Entwicklung fachlicher Problemlösekompetenzen.
  Im Vortrag soll herausgearbeitet werden, unter welchen Bedingungen Lernende tatsächlich kognitiv aktiviert sind und warum dies gerade im Physikstudium von besonderer Bedeutung ist. Ausgangspunkt bilden aktuelle Herausforderungen in der Hochschullehre, die die Gestaltung lernwirksamer Lehrveranstaltungen zunehmend beeinflussen. Dazu zählen insbesondere Veränderungen im mathematisch-physikalischen Vorwissen der Studienanfängerinnen und Studienanfänger sowie ein zunehmend heterogenes Lernverhalten. Diese Entwicklungen erschweren die traditionelle Wissensvermittlung im Physikstudium und machen es notwendig, Studierende stärker in aktive Denkprozesse einzubinden. Vor diesem Hintergrund stellt sich die Frage, wie Lehrveranstaltungen so gestaltet werden können, dass Studierende systematisch physikalische Denk- und Arbeitsweisen einüben und sich Inhalte eigenständig erschließen.
  Ein Schwerpunkt des Vortrags liegt auf der Präsentation konkreter Beispiele aus der universitären Physiklehre. Vorgestellt werden aktivierende Elemente wie die Integration studentischer Diskussionen zu konzeptionellen Fragen in der Vorlesung (Peer Instruction), der gezielte Einsatz von Lösungsbeispielen zum Aufbau von Problemlösestrategien, strukturierte Formate zum aktiven Nacharbeiten von Vorlesungen sowie kooperative Arbeitsphasen in Kleingruppen. Anhand konkreter Umsetzungen wird diskutiert, wie diese Ansätze in bestehende Vorlesungen und Übungen integriert werden können und welche Erfahrungen dabei gemacht wurden. Der Vortrag richtet sich damit an Fachwissenschaftlerinnen und Fachwissenschaftler, die ihre Lehre stärker auf aktives physikalisches Denken der Studierenden ausrichten möchten, sowie an Studierende.

  PAF Colloquium

• Gita Palizban - TBA

  External link de

  Thursday 21 May 2026, 14:00 - 15:45 PM, Abbeanum, Straubel-HS

  Quantum Theory Seminar

• Prof. Yong-Zhong Qian - TBA

  External link de

  Wednesday 27. May 16:15 - 18:15 PM, Abbenaum, Straubel-HS

  Seminar of the institute

• Simulating the transient sky

  External link

  Monday 8 June, 12:00 - 18:00 PM, Abbeanum, SR 102
  
  A central goal of the workshop is to highlight key open questions in the field: What are the dominant mechanisms shaping electromagnetic counterparts of mergers? How do microphysical processes—such as neutrino transport, magnetic field amplification, and radiation transfer—impact observable signatures? What limits current simulations, and how can they be overcome to achieve predictive power across scales? By addressing these challenges, the workshop aims to foster collaboration and identify promising directions for the next generation of transient sky modeling.

  Workshops

• Sanika Samir Khadkikar - From Cradle to Grave: Interpreting the Extraordinary Lives of Neutron Stars through multimessenger observations

  External link de

  Friday 22 May 2026, 16:00 18:00 PM, Abbenaum Straubel HS
  
  Neutron stars are among the most extraordinary objects in the Universe, formed in the aftermath of stellar collapse, evolving through lives that broadcast their internal structure across almost every messenger we can detect, and dying in mergers expected to be responsible for the production of a significant fraction of heavy elements in the Universe. In this talk, I follow them from their cradle to their grave, examining the imprints of their internal properties, including temperature, rotation, composition, and the possible presence of dark matter, strange matter, or deconfined quark matter, on observable signatures across electromagnetic and gravitational wave channels throughout their lives. I will discuss the inherent degeneracies among these signatures that complicate efforts to infer the underlying microphysics, and present strategies for bias-aware, systematically robust inference aimed at deconvolving these effects. Using this framework, I aim to consistently connect gravitational wave measurements to electromagnetic observations, working towards a unified multi-messenger picture of neutron star interiors and heavy-element production in the Universe.

  General Relativity Seminar

• Prof. Dr. Marika Taylor - The black hole information paradox

   de

  Monday 22 June, 16:15 - 17:45 PM, Abbenaum, HS 1
  
  Fifty years ago, Stephen Hawking showed that black holes emit radiation due to quantum effects. The discovery of Hawking radiation has led to a longstanding puzzle about the nature of black holes. This is the information paradox, the question of what happens to information that falls into a black hole. In this colloquium we will explain the information paradox, and discuss why it is so important for understanding the quantum nature of gravity. We will explore contemporary ideas for resolving the paradox, and how these may relate to quantum computing.

  PAF - Kolloquium