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Calendar of Physics Talks Vienna
| Metric reconstruction for non-radiative spacetimes |
| Speaker: | Roberto Oliveri (LUTH, Paris Meudon) |
| Abstract: | Multipole moments are important quantities to characterize spacetimes. In General Relativity, the most general vacuum solution with no incoming radiation is parametrized by two sets of infinite multipole moments. In this talk, we focus on non-radiative spacetimes and provide a characterization thereof in terms of a tower of multipole moments. This tower encodes non-radiative and non-stationary features of the gravitational field at null infinity, and generalizes the Geroch-Hansen moments for stationary spacetimes. Moreover, such a tower of moments is identified with charges associated to the ð¿ð¤1+â algebra recently discovered in the structure of asymptotically flat spacetimes. |
| Date: | Tue, 28.06.2022 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Sem.R. DA, gruen 05 (TU Wien, Freihaus, Wiedner Hauptstrasse ) Zoom https://univienna.zoom.us/j/64871597658?pwd=eDdWUEIwd0l5Z211RkovWVZhdE9xUT09 ID meeting: 648 7159 7658 Passcode: 641201 |
| Contact: | S. Fredenhagen, D. Grumiller, E. Battista, R. Ruzziconi |
| IMBM Seminar: Generalized Clausius inequality, error tolerant memory and the quantum null energy condition |
| Speaker: | Ayan Mukhopadhyay (Indian Institute of Technology, Madras) |
| Abstract: | Quantum thermodynamics generalizes Clausius inequality stating that the irreversible entropy production is not only positive, but also has both a lower and an upper bound for a given physical process. We show that the study of the quantum null energy condition in holographic quenches gives explicit upper and lower bounds for the irreversible entropy production and also entanglement growth in two dimensional systems. We also apply these methods to obtain a refined version of Landauer principle, in which we compute the minimum irreversible entropy production needed to delete encoded quantum information, and obtain analytic results for a large number of encoding qubits. We find that, for certain forms of encoding, fast deletion is impossible if the encoded bits are squeezed over a sufficiently small length scale. This circumvents no-go theorems based on stabilizer codes. |
| Date: | Thu, 30.06.2022 |
| Time: | 16:30 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, Sem.R. DB gelb 09 |
| Contact: | Iva Lovrekovic |
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