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Calendar of Physics Talks Vienna
| Applications of holographic QCD and the role of anomalous symmetries (Vienna Theory Lunch Seminar) |
| Speaker: | Jonas Mager (TU Wien) |
| Abstract: |
This talk will present applications of holographic models of QCD to interesting processes in hadron physics. In some way or another most of these processes involve anomalous symmetries. Holographic models of QCD are often particularly good at reproducing the symmetries of the dual theory and their anomalies, hence the predictions for these observables are of special interest. In particular, I will show different ways the U(1)_A anomaly can be realised in holographic models and subsequently broken by quark masses, during which we will encounter interesting concepts such as superconnections and tachyon condensation. I will present numerical results for observables, such as hadronic light by light scattering, double photon decay of mesons and [...]
[[part of the "Vienna Theory Lunch Seminar, see https://lunch-seminar.univie.ac.at ]] |
| Date: | Tue, 23.01.2024 |
| Time: | 12:30 |
| Duration: | 75 min |
| Location: | TU Wien: Wiedner Hauptstr. 8-10, yellow area, 10th floor, seminar room DB10E11 |
| Contact: | Florian Lindenbauer |
| A Combinatorial Derivation of the Standard Model Particles from the Dirac Lagrangian |
| Speaker: | Charlie Beil (University of Graz) |
| Abstract: | I will begin by introducing a modification to general relativity where time is stationary along the worldlines of fundamental particles. The aim of this new geometry is to describe certain quantum phenomena using (classical) spacetime metrics which are degenerate. For example, on such a spacetime the dimensions of tangent spaces vary, and spin wavefunction collapse is modeled by the projection from one tangent space to another. I will then describe how the free Dirac Lagrangian on such a spacetime yields the standard model particles.
Specifically, we obtain three generations of leptons and quarks, the electroweak gauge bosons, and the Higgs boson -- all with their correct spin, electric charge, and color charge -- together with precisely one new massive spin-2 boson. Finally, I will show how the trivalent interaction vertices arise from the combinatorics of the Dirac Lagrangian subject |
| Date: | Tue, 23.01.2024 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | TU Wien Freihaus, Wiedner Hauptstrasse 8, 3rd floor, yellow tower, Sem. R. DB gelb 03 |
| Contact: | S. Fredenhagen, D. Grumiller, T. Tran, A. Fiorucci |
| Photocurrents induced by structured terahertz radiation |
| Speaker: | Sergey Tarasenko (Ioffe Institute, St. Petersburg) |
| Abstract: | Structured radiation, such as twisted beams carrying orbital angular momentum, has a great potential for the use in optics and optoelectronics. Here, we explore the interaction of structured terahertz radiation with two-dimensional electron systems and show that the structured radiation can drive dc electric currents and currents at double frequency. The currents can be related to the spatial gradients of the intensity, Stokes polarization parameters, and phase of the electromagnetic field. We discuss the physics of such effects and the microscopic mechanisms of the current generation.
A.A. Gunyaga, M.V. Durnev, and S.A. Tarasenko, Photocurrents induced by structured light, Phys. Rev. B 108, 115402 (2023). |
| Date: | Tue, 23.01.2024 |
| Time: | 16:00 |
| Duration: | 45 min |
| Location: | Freihaus SR DA Grün 06B, https://tuw-maps.tuwien.ac.at/?q=DA06G10 |
| Contact: | Andrei Pimenov |
| Flavour Non-Universal Interactions |
| Speaker: | Gino Isidori (University of Zurich) |
| Abstract: | Flavour physics represents one of the most fascinating puzzles of particle physics.
I will discuss some recent developments in this field, both from a theoretical perspective and from a more phenomenological point of view. I will focus in particular on the idea of flavour non-universal gauge interactions as a way to address the origin of the flavour hierarchies, while enabling new physics at the TeV scale that can stabilise the electroweak sector. The implications of this class of models for various short- and medium-term flavour physics experiments, as well as for new-physics searches at high energies, will also be discussed.
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| Date: | Tue, 23.01.2024 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-Hoersaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, M. Procura |
| Speaker: | Wan Cong (U of Vienna) |
| Abstract: | In a series of work, Aretakis, Czimek, and Rodnianski have studied the gluing of two sets of initial data to the Einstein equations along a null surface. By solving the linearized gluing problem around Minkowski and using the implicit function theorem, they have shown that two sets of C2 "sphere data" sufficiently close to Minkowski can be glued together along a null surface up to a ten dimensional obstruction space. In this talk, I will present a generalisation of this result to (i) higher dimensions, (ii) include the cosmological constant and (iii) the gluing of higher regularity Ck data.
Based on joint work with Piotr Chrusciel and Finnian Gray arXiv:2401.04442 [gr-qc] |
| Date: | Wed, 24.01.2024 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Seminarraum A, Waehringer Strasse 17, 2nd Floor |
| Contact: | P. Chrusciel |
| Spin waves for novel information systems |
| Speaker: | Andrii Chumak (University of Vienna) |
| Abstract: | A disturbance in the local magnetic order of a solid body can propagate in a magnetic material in the form of a spin wave (magnon). Among the key advantages offered by magnons for data processing are the scalability down to atomic dimensions, the compatibility with existing CMOS and spintronic technologies, the operations in the frequency range from GHz to hundreds of THz, the possibility to process data in the wide temperature range, and the access to pronounced nonlinear phenomena.
In my talk, after a general introduction to spin waves, I will address three research directions in which the spin waves and magnons offer particularly high potential: (1) magnon-based processing of Boolean data, (2) the potential of nanoscale spin-wave devices for 5G communication systems, and (3) the first steps towards quantum magnonics at mK temperatures.
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| Date: | Wed, 24.01.2024 |
| Time: | 16:00 |
| Duration: | 45 min |
| Location: | Freihaus SR DC rot 07, https://tuw-maps.tuwien.ac.at/?q=DC07A15 |
| Contact: | Andrei Pimenov |
| Fractons, Carroll, and flat space holography |
| Speaker: | Stefan Prohazka (University of Vienna) |
| Abstract: | Theories with exotic features, like restricted mobility, not only have
interesting connections to phenomenology and flat space holography but
also challenge common quantum field techniques. As a first step, we will
explore the consequences of conserved dipole symmetry and its connection
to fractons. Using the underlying symmetries we will then define
fractons and explain their correspondence to Carroll particles. We will
also discuss field theories with fracton and Carroll symmetry and
provide comments concerning novel infrared effects and relations to flat
space holography. |
| Date: | Thu, 25.01.2024 |
| Time: | 17:00 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, Seminar room on the 10th floor |
| Contact: | Iva Lovrekovic |
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