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Calendar of Physics Talks Vienna
| Methods and Techniques for Realizing Arrays of Levitated Microspheres |
| Speaker: | Benjamin Siegel (Yale University) |
| Abstract: | Levitated microspheres have proven to be extremely sensitive force and momentum detectors, enabling searches for physics beyond the Standard Model. By monitoring the position and charge of such spheres, our lab has already set limits on relic millicharged particles, searched for composite dark matter and detected nuclear decays through mechanical recoils. We plan to improve the sensitivity of these rare event experiments by scaling to an array of traps. Using a time division multiplexing approach to creating the traps enables independent control for each one. We have successfully demonstrated the trapping and reorganization of >50 spheres, with their motion monitored via a high speed camera. Furthermore, we have realized a scalable real-time feedback protocol that is only limited by the bandwidth of our photodiodes and acousto-optic deflectors. This protocol utilizes back focal plane det |
| Date: | Tue, 21.10.2025 |
| Time: | 14:00 |
| Duration: | 45 min |
| Location: | Seminar room ZE-EG New Building ZE |
| Contact: | Uros Delic |
| Ward Identities in String Theory |
| Speaker: | Jnan MAHARANA (IOPB, Bhubaneswar) |
| Abstract: | It is well known that string theories are very rich in symmetry contents. I shall focus on massless sector of closed bosonic string. The effective action is known to be invariant under general coordinate transformations and under 'vector' gauge transformation of 2-form potential. For compactified closed string it admits nonabelian gauge invariance associated with massless gauge excitations. These symmetries are not exhibited by the worldsheet action which respects two-dimensional diffeo-morphism invariance. I shall show how the abovementioned target space local symmetries can be studied in Hamiltonian formulation of the theory in the worldsheet. There are some shortcomings and I shall propose possible resolutions. |
| Date: | Tue, 21.10.2025 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-Lecture Hall, 1090 Vienna, Boltzmanngasse 5, 5th floor |
| Contact: | S. Fredenhagen, M. Sperling |
| Power corrections in the N-jettiness slicing scheme |
| Speaker: | Kirill MELNIKOV (KIT Karlsruhe) |
| Abstract: | I will discuss a systematic way to compute next-to-leading power corrections in the small N-jettiness variable for arbitrary processes with colorless final states, as well as for the process of prompt photon production in association with a jet at a hadron collider. |
| Date: | Tue, 21.10.2025 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-Lecture Hall, 1090 Vienna, Boltzmanngasse 5, 5th floor |
| Contact: | A. Hoang, M. Procura |
| Spinning test particles in black hole fields: Dynamics and inspirals |
| Speaker: | Vojtech WITZANY (Charles University Prague) |
| Abstract: | The motion of spinning test particles in a curved background is a classical topic of General relativity. Currently, it finds applications in the modelling of inspirals of spinning compact objects into massive black holes. In recent years, we have made significant progress in the modelling of the spin contribution to the orbit and outgoing gravitational-wave flux of the compact object in the black-hole field. Technically, this involved a number of tools, ranging from the Hamiltonian formalism to Killing-Yano tensors and the hidden symmetry of black holes. In this talk, I will summarize these developments. |
| Date: | Wed, 22.10.2025 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | VERA Seminar Room (Viktor-Franz-Hess Lecture Hall), Waehringer StraÃe 17, 1090 Vienna, Hoftrakt, 1st floor |
| Contact: | D. Fajman |
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