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Calendar of Physics Talks Vienna
| Quantum Geometry of Data (and Spacetime) |
| Speaker: | Harold STEINACKER (University of Vienna) |
| Abstract: | Quantum geometry provides a suitable framework for a quantum theory of spacetime and gravity defined by matrix models. More recently, the same concept of quantum geometry has been applied in the context of machine learning and data science.
I will describe how "Quantum Cognition Machine Learning" (QCML) encodes data as quantum geometry, by machine learning Her mitian matrices and mapping data points to states in Hilbert space. The quantum geometry description endows the dataset with rich geometric and topological structure, including intrinsic dimension, quantum metric, Berry curvature and Chern numbers. QCML captures global properties of data, while avoiding the curse of dimensionality inherent in local methods. This is illustrated with a number of synthetic and real-world examples. Quantum geometric representation of QCML may help to advance our understanding of cognitive phenomena. |
| Date: | Tue, 14.10.2025 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-Lecture Hall, 1090 Vienna, Boltzmanngasse 5, 5th floor |
| Contact: | S. Fredenhagen, M. Sperling |
| Does the Top Quark Embrace Its Antipode? Unveiling a Pseudoscalar Excess near the $t\bar{t}$ Threshold |
| Speaker: | Christian Schwanenberger (DESY) |
| Abstract: | The top quark plays a unique role at the energy frontier of the LHC. Using CMS data collected between 2016 and 2018 at a CoM energy of √s = 13 TeV, we searched for resonances in $t\bar{t}$ production. The analysis probes the invariant mass of the $t\bar{t}$ system and angular observables that reveal subtle effects of the correlation between the top and antitop quark spins. A significant excess of events appears near the kinematic $t\bar{t}$ threshold, deviating from predictions of fixed-order perturbative QCD. The observed enhancement is consistent with the production of a color-singlet pseudoscalar quasi-bound “toponium’’ state — long thought unobservable — as predicted by non-relativistic QCD. I will present these results, compare them with recent ATLAS findings confirming the excess , and discuss alternative interpretations. |
| Date: | Thu, 16.10.2025 |
| Time: | 10:00 |
| Duration: | 60 min |
| Location: | Besprechungsraum 3A.1/2, PSK, Georg-Coch-Platz 2, 1010 Wien |
| Contact: | Mukul Sholapurkar (MBI, Vienna) |
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