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Calendar of Physics Talks Vienna
| CFTs and Wightman axioms in general dimensions |
| Speaker: | Petr Kravchuk (IAS Princeton) |
| Abstract: | In Conformal Field Theory, one is often concerned with computing local correlation functions from the spectrum of local operators and their OPE coefficients. In general quantum field theories, we expect these correlation functions to satisfy Wightman and Osterwalder-Schrader axioms.
In this talk, I will explain that Wightman axioms are not obvious for CFT correlation functions and then present a proof for correlators up to four points. In the process I will also briefly review the classic results relating Wightman and O-S axioms, which have caveats that are important in the CFT setup. |
| Date: | Tue, 04.05.2021 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | https://moodle.univie.ac.at/mod/bigbluebuttonbn/guestlink.php?gid=x8o6ILSKJuC9 |
| Contact: | S. Fredenhagen, D. Grumiller, T. Schimannek |
| Speaker: | Holmfridur Hannesdottir (Harvard University) |
| Abstract: | The S-matrix is a fundamental object in making theoretical predictions for collider scattering experiments.It is inspired by a well-defined operator in non-relativistic quantum mechanics,but is plagued with both ultraviolet(UV)and infrared(IR)divergences in quantum field theory.While UV divergences are now understood through the program of renormalization IR divergences remain an active area of research.In this talk we explore three solutions to the IR divergence problem:i)The cross section method,ii)modification of the S-matrix and iii)the coherent state formalism.We will show how our modified S-matrix in theories with massless particles can be interpreted as remainder functions in N=4 super Yang-Mills theory,or as Wilson coefficients in Soft-collinear effective theory.Examining its analytic structure thus provides a new probe to properties of familiar object from scattering calculation |
| Date: | Tue, 04.05.2021 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | https://univienna.zoom.us/j/93104933847?pwd=N0FrL0E1UHlkQWRhQTlQODVkZ3kvUT09 Meeting ID: 931 0493 3847 Passcode: 674625 |
| Contact: | A. Hoang, P. Stoffer |
| An insight to MedAustron’s Accelerator Facility |
| Speaker: | Claus Schmitzer (MedAustron Wiener Neustadt) |
| Abstract: | MedAustron is one of only four european centers which offer multispecies ion beams for cancer treatment. While being the biggest treatment center it is also the youngest and has not yet reached full operation or potential. I will present an overview of the centers and give an introduction to the accelerator operation mode as well as some typical issues. I will discuss current developments and ideas for future upgrades. |
| Date: | Tue, 04.05.2021 |
| Time: | 16:00 |
| Location: | The seminar will be held as a Zoom Meeting https://tuwien.zoom.us/j/93352801359?pwd=bWR1WkJMaFFHaTRyOUNDR2x0d2o1UT09 Meeting ID: 933 5280 1359 Passcode: iapsem2021 |
| Contact: | Dr. Richard Wilhelm |
| Perspectives of measuring gravitational effects of laser light and particle beams |
| Speaker: | Felix Maximilian Spengler (Tubingen) |
| Abstract: | High energy laser beams and particle beams, such as the one of the Large Hadron Collider (LHC) at CERN, can be used as lab-scale, relativistic sources of gravitational fields.We present a study of the creation and possibility of detection of oscillating gravitational fields from lab-scale, relativistic sources. Lab-based sources allow for signal frequencies much higher and far narrower in bandwidth than what most celestial sources produce. In addition, by modulating the source beams, the source frequency can be adjusted over a very broad range. In this talk we show an analysis of the gravitational field produced by these sources and the responses of a variety of detectors, with the outlook that an adapted version of a recently experimentally demonstrated high-Q monolithic pendulum might be able to detect the gravitational signal produced by the planned high-luminosity upgrade of the LHC. |
| Date: | Thu, 06.05.2021 |
| Time: | 15:00 |
| Duration: | 60 min |
| Location: | https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09 Meeting ID: 654 003 6841 Passcode: Gs4brS |
| Contact: | Piotr Chrusciel, David Fajman |
| Einstein's equivalence principle for quantum reference frames and spacetimes |
| Speaker: | Caslav Brukner (Universität Wien) |
| Abstract: | The equivalence principle is at the core of general relativity, stating that all physical laws take their special-relativistic form in any local inertial frame. However, its formulation implicitly assumes reference frames as classical (i.e., constructed from classical rods and clocks), and that the background spacetime is well-defined. The questions then arise whether the principle also holds for "quantum reference frames" (QRF) (i.e., when quantum systems are taken as reference frames), and in a superposition of classical spacetimes. In my talk, I will address both questions by introducing the "quantum local inertial frame" attached to a free-falling quantum system in curved spacetime, or in a superposition of spacetimes. I will then show that from the perspective of such a QRF, the metric looks locally flat. Consequently, one cannot distinguish with a local measurement whether the spac |
| Date: | Fri, 07.05.2021 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | on-line |
| Contact: | Jörg Schmiedmayer |
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