Calendar of Physics Talks Vienna

Elements of Celestial Conformal Field Theory
Speaker:Stephan Stieberger (Max Planck Institute, Munich)
Abstract:I will introduce into subject of holographic description of four-dimensional massless physics as conformal field theory on the celestial sphere and report on progress on celestial conformal field theory (CCFT). In celestial holography, four-dimensional scattering amplitudes are considered as two-dimensional conformal correlators of a putative two-dimensional CCFT. The simplest way of converting momentum space amplitudes into CCFT correlators is by taking their Mellin transforms with respect to light-cone energies. For massless particles, like gluons, however, such a construction leads to three-point and four-point correlators that vanish everywhere except for a measure zero hypersurface of celestial coordinates. This is due to the four-dimensional momentum conservation law that constrains the insertion points of the operators associated with massless particles [...]
Date: Tue, 24.01.2023
Time: 14:00
Duration: 60 min
Location:Erwin-Schrödinger-Hörsaal (University of Vienna, Boltzmanngasse 5, 5th floor, Room Nr. 3500)
Contact:D. Grumiller, S. Fredenhagen, E. Battista, R. Ruzziconi

Towards identifying the charge carriers in tribocharging
Speaker:Markus Felber (TU Wien, IAP, FB Angewandte Grenzflächenphysik)
Abstract:If two electrically neutral materials are brought into contact, an exchange of charge can occur. This effect is called tribocharging and has been known for over 2500 years, yet it is still poorly understood. Perhaps the most important unresolved issue is the unknown identity of the charge-carrier itself. While it is often assumed that the carriers are electrons, they could also be ions, and different experiments in different circumstances provide suggestive evidence for both cases. In order to address this fundamental issue, an experiment whose aim is to clearly identify the carrier responsible for tribocharging is being built. For this, tribocharging experiments with insulating samples in vacuum are being carried out. After contact and charge exchange, we heat one sample near the entrance to a single-charge sensitive quadrupole mass spectrometer (QMS), which can measure ionic charges le
Date: Tue, 24.01.2023
Time: 16:00
Location:TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner Hauptstraße 8-10 Yellow Tower „B“, 5th floor, SEM.R. DB gelb 05 B htt
Contact:Univ.Prof. M. Valtiner

Touch science and engineering: from biomedical applications and tactile restoration with neuromorphic information encoding to sensory enrichment for the metaverse
Speaker:Calogero Maria Oddo (The BioRobotics Institute and Department of Excellence in Robotics & AI Interdisciplinary Research Center Health Science Sant’Anna School of Advanced Studies, Pisa, Italy)
Abstract:The talk will discuss selected case studies of technologies developed for endowing robots with artificial tactile sensors that are distributed over large areas and to deliver tactile feedback for the metaverse. In the presented scientific approach, robotic systems are developed by capitalizing on a fertile interaction between robotics and neuroscience, so that the advancements of neuroscientific research can lead to the development of more effective technologies, which in turn contribute to the fundamental understanding of physiological processes. A first case study proposed is with piezoresistive MEMS sensors, applied to bionic hand prostheses to restore rich tactile skills, such as texture discrimination, in upper limb amputees. The developed biorobotic technologies and artificial intelligence methods, based on information encoding with neuromorphic spikes emulating physiological tacti
Date: Tue, 24.01.2023
Time: 16:00
Location:TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner Hauptstraße 8-10 Yellow Tower „B“, 5th floor, SEM.R. DB gelb 05 B
Contact:Univ.Prof. Dr. Markus Valtiner

An MCMC Revision of the Universal Texture Zero of Flavor
Speaker: Ronald James Talbert Jr. (Cambridge)
Abstract:In this talk I plan to address an old problem of particle physics (the flavor puzzle) with an aging solution(a broken non-Abelian discrete symmetry),albeit with a rather novel phenomenological technique:a simple Markov Chain Monte Carlo (MCMC) algorithm. Indeed the ‘Universal Texture Zero’ (UTZ) effective theory I co-authored in 2017 was argued to successfully resolve the mass, mixing,and CP-violating structure of both the quark and lepton flavor sectors of the Standard Model with as few as nine infrared model parameters, and in a manner consistent with ultraviolet Grand Unification. However, the original 2017 numerical analysis was insufficient to exhaustively explore even this minimal parameter space, much less that of the augmented next-to-leading order (NLO) UTZ effective Lagrangian,and was not capable (e.g.)of making robust predictions for the leptonic Dirac CP-violating phase ....
Date: Tue, 24.01.2023
Time: 16:15
Duration: 60 min
Location:Fakultaet fuer Physik, Erwin Schroedinger-HS, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, M. Procura, T. Corbett

Towards couplimg an atom array to an optical cavity
Speaker:Stephan Roschinski (TU Wien, Atominstitut)
Abstract:A central goal of current research is to efficiently create entangled states among an increasing number of qubits. While atomic platforms provide great scalability, they mostly rely on local interactions, for instance, collisional or Rydberg interactions. We describe the progress to build a novel platform to entangle atoms with non-local operations using photon-mediated interactions. The atoms will be trapped within individual optical tweezers which are coupled to the field of an optical cavity. Large optical access through a high-resolution microscope objective will enable us to individually address each atom and control its coupling with all-to-all connectivity. Further advantages of this platform include partial non-destructive readout and efficient multi-qubit entanglement operations. In the long term, the proposed platform provides a scalable path to studying many-body systems with
Date: Wed, 25.01.2023
Time: 16:15
Duration: 45 min
Location:Hörsaal ATI
Contact:Julian Leonard

Gluing small black holes into initial data sets
Speaker:Peter Hintz (ETH Zuerich)
Abstract:We describe a localized gluing result for the constraint equations in which a small mass rescaling of an asymptotically flat data set is glued into the neighborhood of a point inside of another data set. As the smallness parameter tends to zero, rescalings of normal coordinates around the point become asymptotically flat coordinates on the asymptotically flat data set. As an application, we construct initial data for the Einstein vacuum equations which conjecturally evolve into extreme mass ratio inspirals.
Date: Thu, 26.01.2023
Time: 15:30
Duration: 60 min
Location:via ZOOM https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09
Contact:P. Chrusciel, D. Fajman

Quantum- and nano-optics with tunable microcavities
Speaker:David Hunger (Karlsruhe Institute of Technology)
Abstract:Optical microcavities are a powerful tool to enhance light-matter interactions. This enables applications ranging from ultra-sensitive spectroscopy and sensing to quantum information. To achieve large cavity enhancement on a flexible platform, we have developed microscopic Fabry-Perot cavities based on laser-machined optical fibers. In the context of sensing, we use microcavities for imaging and spectroscopy applications, as well as for sensing of dynamic properties of individual nanosystems. We have developed scanning cavity microscopy as a versatile method for spatially and spectrally resolved maps of various optical properties of a sample with ultra-high sensitivity. Simultaneous enhancement of absorptive, dispersive, and scattering signals promises intriguing potential for optical studies of nanomaterials, molecules and biological nanosystems. For quantum information applications, we
Date: Fri, 27.01.2023
Time: 11:15
Duration: 45 min
Location:ATI Hörsaal/https://tuwien.zoom.us/j/93672218922?pwd=dEZNQ2liVzRNNURvNmVWVE5KUWRiQT09
Contact:Sarah Bayer-Skoff