Seminars this week

Programm für das Sommersemester 2024

s,  Uhr

11.06.24Dr. Karen Alim, TU München
Propagating, storing and processing information is key to take smart decisions – for organisms as well as for autonomous devices. In search for the minimal units that allow for complex behaviour, the slime mould Physarum polycephalum stands out by solving complex optimization problems despite its simple make-up. Physarum’s body is an interlaced network of fluid-filled tubes lacking any nervous system, in fact being a single gigantic cell. Yet, Physarum finds the shortest path through a maze. We unravel that Physarum’s complex behaviour emerges from the physics of active flows shuffling through its tubular networks. Flows transport information, information that is stored in the architecture of the network. Thus, tubular adaptation drives processing of information into complex behaviour. Taking inspiration from the mechanisms in Physarum we outline how to embed complex behaviour in active microfluidic devices and how to program human vasculature.
Slides here...
16:15 Uhr s.t., HS KPH

11.06.24Melissa van Beekveld, Nikhef
Parton showers are essential tools for interpreting particle-collision data. To get the most out of available and upcoming data, it is important that these showers incorporate state-of-the-art theoretical predictions. The PanScales project aims to design parton showers that achieve higher logarithmic accuracy than any of the standard tools used at present. This talk will discuss the construction of logarithmically accurate parton showers, including the recent achievement of next-to-next-to-leading-logarithmic accuracy for the wide class of e+e- observables known as event shapes, and its impact on phenomenology.
14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor)

12.06.24Prof. Dr. Jessica Turner, IPPP, Durham University, UK
I will discuss how proton decay, combined with gravitational waves, can be used to test Grand Unified Theories (GUTs). In particular, proton decay searches by large multipurpose neutrino experiments such as DUNE, Hyper-Kamiokande, and JUNO will either discover proton decay or further push the symmetry-breaking scale above 10^16 GeV. Another possible observational consequence of GUTs is the formation of a cosmic string network produced during the breaking of the GUT to the Standard Model gauge group, which can produce a stochastic background of gravitational waves. Several gravitational wave detectors will be sensitive to this over a wide frequency range. I will demonstrate the non-trivial complementarity between the observation of proton decay and gravitational waves produced from cosmic strings in determining SO(10) GUT breaking chains and their compatibility with leptogenesis as a means of producing the observed matter-antimatter asymmetry. Additionally, I will extend this discussion to include supersymmetric GUTs, taking into account recent findings from Pulsar Timing Arrays that have detected gravitational waves in the nanoHertz frequency range.
13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7

12.06.24Apratim Chatterji, Prof
Under high cylindrical confinement, segments of ring polymers with internal loops can be made to get localized along the long axis of the cylinder. The emergent organization of the polymer segments occurs because of the entropic repulsion between internal loops which mutually exclude each other position along the long axis of the cylinder [Phys.Rev.E, 106, 054502 (2022)]. We used these localization properties of segments in such topologically modified bead-spring models of ring polymers to identify the underlying mechanism of the evolution of bacterial chromosome organization as the cell goes through its life cycle [Soft Matter 18, 5615-5631 (2022)]. Here, we show how to modify ring polymer topology by creating internal loops of two different sizes within the polymer, and thereby create an asymmetry in the two halves of the modified ring- polymer. This allows us to strategically manipulate and harness entropic interactions between adjacent polymers confined in a cylinder, such that a polymer prefers to orient itself in a specific way with respect to its neighbours. Thus, we can induce entropy driven effective interactions reminiscent of Ising-spin like interactions between adjacent topologically modified polymers. We consider a completely flexible bead-spring model of polymers with only excluded volume interactions between the monomers. We extend the work to investigate the entropic organization of topologically modified ring- polymers confined within a sphere. We observe that for a single topologically modified polymer within a sphere, the monomers of the bigger loop are statistically probable to be found closer to the periphery. However, the situation is reversed when we have multiple such topologically modified polymers in a sphere. The monomers of the small loops are found closer to the walls of the sphere. We can increase this effect by introducing a large number of small loops in each ring polymers.
15:30 Uhr s.t., Lorentz-Raum, 05-119, Staudingerweg 7

13.06.24Prof. Eugene Polzik, University of Copenhagen, Denmark
Studies of extreme cases within quantum mechanics have always been particularly attractive. How macroscopic can objects be and still demonstrate unique quantum features, such as entanglement? What are the real limits of measurement precision in quantum mechanics? I will review our experiments where macroscopic objects are driven deep into the quantum regime. Observation of a quantum trajectory of motion in a quantum reference frame with, in principle, unlimited accuracy will be presented. A concept of a reference frame with an effective negative mass required for such observation will be introduced. Generation of an entangled Einstein-Podolsky-Rosen state between distant mechanical and atomic oscillators and progress towards application of those ideas to gravitational wave detection will be reported. Finally, a recent demonstration of entanglement enhanced magnetic induction tomography for medical applications will be presented.
14 Uhr c.t., IPH Lorentzraum 05-127