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Calendar of Physics Talks Vienna
| Speaker: | Ron Folman (Ben Gurion University) |
| Abstract: | Realization of a complete Stern-Gerlach interferometer: Towards a test of quantum gravity.
You will find further information & zoom link on https://vcq.quantum.at/colloquium-ws-22/ |
| Date: | Mon, 05.12.2022 |
| Time: | 17:30 |
| Duration: | 90 min |
| Location: | Lise Meitner Lecture Hall, Boltzmanngasse 5 |
| Contact: | VCQ Admin Team |
| Discrete fluxes, higher-form symmetries and Ward identities |
| Speaker: | Siye Wu (National Tsing Hua University, Taiwan) |
| Abstract: | We study discrete electric and magnetic fluxes in gauge theories from algebraic and topological viewpoints.
We explain that they can not be simultaneously specified in a sector of quantum Hilbert space.
This is the uncertainty of fluxes discovered previously in Abelian gauge theories.
We further interpret the discrete fluxes as charges of higher-form symmetries, which leads to an enhanced understanding
of the latter in terms of cohomology groups of spacetime with coefficients in a group.
More generally, higher-form symmetries exist whenever there are constant gauge transformations.
Finally, we explore the relations to Noetherâs second theorem and higher Ward identities. |
| Date: | Tue, 06.12.2022 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-Hoersaal, Fakultaet für Physik, Boltzmanngasse 5, 5. Stock |
| Contact: | S. Fredenhagen, D. Grumiller, E. Battista, R. Ruzziconi |
| Advances in subleading power factorization and resummation |
| Speaker: | Dr Sebastian Jaskiewicz (Inst. for Particle Physics Phenomenolog, Durham University) |
| Abstract: | Precise theoretical predictions are a key ingredient in ongoing tests of the Standard Model and in searches for physics beyond it.Since its inception twenty years ago,Soft Collinear Effective Theory(SCET)has been successfully applied to improve the precision of many important observables in collider physics.It is now standard practice to use SCET to derive factorisation theorems and apply renormalisation group (RG) methods to achieve leading power resummation of large logarithms that appear in regions of phase space with disparate energy scales.In this talk,I will discuss the recent advances in taking the step beyond the leading term in the power expansion.Focusing on the threshold Drell-Yan process, I will explain how the general factorisation formula can be derived and I will discuss new objects that emerge beyond leading power: collinear jet functions and generalised soft functions. |
| Date: | Tue, 06.12.2022 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultaet fuer Physik, Erwin Schroedinger-HS, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, M. Procura, A. Broggio |
| Decoherence limit of quantum systems obeying generalized uncertainty principle: new paradigm for Tsallis thermostatistics |
| Speaker: | Petr Jizba (CTU, Prague) |
| Abstract: | The generalized uncertainty principle (GUP) is a phenomenological model whose purpose is to account for a minimal length scale (e.g., Planck scale or characteristic inverse-mass scale in effective quantum description) in quantum systems. In my talk I will discuss possible observational effects of GUP systems in their decoherence domain. I first derive coherent states associated to GUP and unveil that in the momentum representation they coincide with Tsallis' probability amplitudes, whose non-extensivity parameter q monotonically
increases with the GUP deformation parameter β. Secondly, for β<0 (i.e., q<1), I show that, due to Bekner-Babenko inequality, the GUP is fully equivalent to information-theoretic uncertainty relations based on Tsallis-entropy-power. Finally, I invoke the Maximal Entropy principle known from estimation theory to reveal connection between the quasi-classical ... |
| Date: | Wed, 07.12.2022 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | TU Wien, SEM grün DA 02 A (Wiedner Hauptstrasse 8, 1040 Vienna, Freihaus, 2nd floor) |
| Contact: | Daniel Grumiller |
| The fate of the light ring instability |
| Speaker: | Pedro Cunha (University of Aveiro, Portugal) |
| Abstract: | The ringdown and shadow of the astrophysically significant Kerr Black Hole(BH)are both intimately connected to a special set of bound null orbits known as Light Rings(LRs).Similarly,ultracompact objects with LRs but without an horizon could mimic BHs in some of their strong gravity phenomenology.However,are such ultracompact objects dynamically viable?Stationary and axisymmetric ultracompact objects that can form from smooth,quasi-Minkowski initial data must have at least one stable LR,which has been argued to trigger a spacetime instability.Until recently its development and fate had been unknown.We confirm that the LRs indeed triggered an instability in fully non-linear numerical evolutions of ultracompact bosonic stars free of any other known instabilities.The results shows that the LR instability can be effective in destroying horizonless ultracompact objects that could be . . . |
| Date: | Wed, 07.12.2022 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | Fakultaet fuer Physik, Seminarraum A, Waehringer Strasse 17, 2. Stock |
| Contact: | P. Chrusciel, D. Fajman, M. Oancea |
| Quantum electromagnetic viscosity |
| Speaker: | Francesco Intravaia (Humboldt University of Berlin) |
| Abstract: | The motion of objects in vacuum has fascinated scientists for centuries. Understanding the
physics at work in these circumstances has wide fundamental and technological implications,
ranging from nanosciences to cosmology.
In particular, the last ten years have witnessed an increasing number of investigations addressing
nonequilibrium interactions in which the (quantum) electromagnetic fluctuations in vacuum can behave as a viscous medium. Examples are blackbody and quantum friction, i.e., contactless drag forces that hinder the motion of an object aiming at bringing it to rest. Blackbody and quantum friction are the manifestations of a phenomenon that can be called quantum electromagnetic viscosity. Interestingly, a careful and self-consistent theoretical description of this phenomenon revealed to be challenging and predictions have varied widely in the past. Recently, consensus is |
| Date: | Fri, 09.12.2022 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | ATI Hörsaal/https://tuwien.zoom.us/j/93672218922?pwd=dEZNQ2liVzRNNURvNmVWVE5KUWRiQT09 |
| Contact: | Rene Sedmik |
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