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Calendar of Physics Talks Vienna
| 3d N=4 Chern-Simons matter theories, twisted traces, and dualities - online on Zoom |
| Speaker: | Leonardo Santilli (Fudan University, Shanghai, SIMIS Shanghai) |
| Abstract: | Every 3d N=4 theory carries two non-commutative algebras, which are the deformation quantization of the maximal branches of the moduli space of vacua. I will review a conjecture for the familiar quiver gauge theories, relating the sphere partition function to twisted traces on modules over these algebras. The conjecture relies crucially on the assumption that the gauge theory admits topologically-trivial massive vacua. I will show how to extend this conjecture to Chern-Simons-matter theories, which do not satisfy the crucial assumption. Along the way, I will present new Abelian dualities between Chern-Simons-matter theories and gauge theories with higher charges. Based on arXiv:2604.20959
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| Date: | Tue, 19.05.2026 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-HS, Boltzmanngasse 5, 1090 Wien, 5.Stock |
| Contact: | S. Fredenhagen, M. Sperling |
| Foliations of asymptotically Schwarzschildean lightcones by surfaces of constant spacetime mean curvature |
| Speaker: | Markus Wolff (University of Vienna) |
| Abstract: | We construct asymptotic foliations of asymtotically Schwarzschildean lightcones by surfaces of constant spacetime mean curvature (STCMC). For a surface in an ambient spacetime, the spacetime mean curvature is defined as the (Lorentzian) length of the co-dimension 2 mean curvature vector. Asymtotic foliations of asymptotically flat spacelike hypersurfaces by STCMC surfaces have previously been constructed by Cederbaum-Sakovich to define a geometric notion of center of mass. Our construction is motivated by the approach of Huisken-Yau in employing a geometric flow. We show that any initial surface within a sufficient a-priori class converges exponentially to an STCMC surface under area preserving null mean curvature flow. We further show that the resulting STCMC surfaces form an asymptotic foliation that is unique within the given a-priori class. This is joint work with Klaus Kröncke. |
| Date: | Wed, 20.05.2026 |
| Time: | 11:30 |
| Duration: | 60 min |
| Location: | BZ02, Oskar-Morgenstern-Platz 1, 1090 Wien, 2. Stock |
| Contact: | D. Fajman |
| Neutron Stars and Binary Mergers as Probes of Dense QCD Matter |
| Speaker: | Christian Ecker (Frankfurt Goethe U.) |
| Abstract: | Astrophysical measurements, in particular gravitational waves from binary neutron star mergers, offer a unique observational window onto QCD matter at densities that are currently inaccessible to first-principles theory and laboratory experiments. I will discuss how recent theoretical developments in chiral effective field theory and perturbative QCD, together
with astrophysical observations, can be combined to constrain the dense-matter equation of state. I will also show how these constraints may be further tightened by future observations
of the post-merger gravitational-wave signal. Finally, I will describe how holographic QCD, a non-perturbative approach rooted in gauge/gravity duality, can be used to make predictions
for the critical end point in the QCD phase diagram and for the possible formation of quark matter in neutron star mergers. |
| Date: | Wed, 20.05.2026 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | SEM 10th floor, Freihaus, TU Wien, Wiedner Hauptstrasse 8, 1040 Vienna |
| Contact: | Daniel Grumiller |
| Nuclear Clock - It's About Time |
| Speaker: | Felix Schneider (Atominstitut, TU Wien) |
| Abstract: | Nuclear clocks based on the low-lying first excited state of Thorium-229 have been first proposed around two decades ago. Since then, we have made considerable progress with a first realization of the clock now pending publication. In this talk, we will walk through the building blocks of what makes a nuclear clock: precision spectroscopy of the Thorium-299 isomer transition structure, the laser clockwork behind it and how the parts come together. We will discuss how to compare clocks and first preliminary results of the recent Thorium-299 to Ytterbium single-ion clock comparison campaign. |
| Date: | Wed, 20.05.2026 |
| Time: | 16:15 |
| Duration: | 45 min |
| Location: | Atominstitut, Helmut Rauch Hörsaal |
| Contact: | Elena Redchenko |
| Exploring Fermionic Quantum Matter at the Single-Atom Level |
| Speaker: | Tarik Yefsah (Laboratoire Kastler Brossel ) |
| Abstract: | The last decades have seen the emergence of ultracold atom experiments as powerful platforms for the exploration of complex many-body systems, owing to their ability to probe large ensembles of particles in a well-characterized, tunable, and isolated environment.
Among the various quantum many-body problems within reach of quantum gas experiments, interacting fermionic systems play a special role. While they constitute a cornerstone of quantum matter covering a broad fundamental and technological scope, their understanding still represents a major challenge for existing theoretical approaches, which are widely plagued by the infamous sign-problem.
In this talk, I will present our recent work on quantum gas microscopy of fermionic many-body systems in continuous space, how we characterize them at previously inaccessible levels of resolution, and gain new insight into their microscopic |
| Date: | Fri, 22.05.2026 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | Helmut Rauch Hörsaal ATI |
| Contact: | Andreas Schindewolf |
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