10.04.2025          Prof. Reza Kamachali / Jun.-Prof. Diana Khoromskaia

Vortragsankündigung [PDF]

Antrittsvorlesungen

24.04.2025          CRC 1459 Colloquium / Prof. J. Boekhoven & Prof. P. ten Wolde

Vortragsankündigung [PDF]

08.05.2025          Prof. Eric Laenen (NIKHEF and Univ. of Amsterdam and Utrecht)

Vortragsankündigung [PDF]

The European Particle Physics Strategy, Future Circular Collider and CERN

This year and the next few will be crucial for the future of CERN and particle physics in Europe. This future is being shaped through the European Strategy for Particle Physics (ESPP) update, which is currently ongoing. A key input is the recently released feasibility study for the possible Future Circular Collider (FCC) at CERN. In this talk I will review the governance of CERN, the ESPP process and its status, the finding of the feasibility study, and what physics could be done such a collider.

15.05.2025          Prof. Michael Kues (IOP, Leibniz University Hannover)

Vortragsankündigung [PDF]

Non-classical frequency combs and processing for quantum networks

Today’s quantum technology relies on the realization of large-scale non-classical systems in practical network-compatible formats to enable quantum resource sharing, secure communications and distributed quantum-accelerated computing. Optical quantum frequency combs, characterized by many equidistantly spaced frequency modes, allow the storage of large amounts of quantum information and together with telecom-compatible control mechanisms can provide practical large-scale quantum systems for the realization of scalable quantum networks. In this presentation, I show the fully laser-integrated generation of quantum frequency combs and the realization of practical coherent quantum frequency processing circuits. I will discuss the advantages of the frequency-based processing capability and show two application examples; the realization of a Serrodyne transceiver for hybrid quantum-classical signal transmission and, the demonstration of entanglement-based frequency-bin quantum key distribution with massively reduced hardware use and multiplexing capabilities. These results contribute to realizing the complexity-reduced, scalable deployment of large-scale quantum networks.

22.05.2025          Prof. Bruce Allen (MPI für Gravitationsphysik, Hannover)

Vortragsankündigung [PDF]

Pulsar timing arrays and the detection of low-frequency gravitational waves

Pulsar timing arrays (PTAs) detect gravitational waves (GWs) via the correlations they create in the arrival times of pulses from different pulsars. The mean correlation, a function of the angle between the directions to pulsars, is called the Hellings and Downs (HD) curve. Observation of this pattern is key evidence that the timing residuals arise from GWs, so PTAs "reconstruct the HD curve" by estimating the inter-pulsar correlation using pulsar pairs separated by similar angles. I'll talk about how PTAs work, and about a recent paper with Joe Romano (PRL 134, 031401, 2025) where we examine the reasons why the HD reconstruction differs from the mean, and estimate the variance. I'll also talk about some work in progress, to extend this to a harmonic space description.

03.07.2025          Sommerfest IG1 (FB Physik)

10.07.2025          Prof. Hartmut Löwen (Theoretische Physik, HHU Düsseldorf)

Vortragsankündigung [PDF]

Physics of active matter

While ordinary materials are typically composed of inert "passive" particles, active matter comprises objects or agents which possess an intrinsic propulsion. Examples are living systems like schools of fish, swarms of birds, pedestrians and swimming microbes but also artificial particles equipped with an internal motor such as robots and colloidal Janus particles. Active matter is praised for possible technological applications ranging from micro-surgery to environmental cleaning. This talk provides an introduction to the basic physics of active matter with an emphasis on the statistical mechanics of synthetic artificial self-propelled particles. After an introduction of basic concepts to describe self-propelled colloids in the mesoscopic soft matter regime, such as active Brownian motion, novel collective phase transitions are described including motility-induced phase separation of repulsive self-propelled particles. Then the importance of inertia relevant for particles of larger size is discussed. Finally two possible paths to next generation's active materials are pointed out: either functionalized microswimmers equipped with artificial intelligence or ultracold atoms in optical fields opening the door to the new field of quantum active matter.