|
Calendar of Physics Talks Vienna
| M-brane Realisation in Matrix Model |
| Speaker: | Yuhma Asano (Universität Wien) |
| Abstract: | In this talk, we consider a one-dimensional matrix model, called the BMN matrix model, which is considered as a non-perturbative formulation of M-theory.
In the BMN matrix model, there are some evidences that spherical M2- and M5-branes correspond to vacua of the matrix model.
While it is easy to understand realisation of M2-brane geometries because the vacua form fuzzy 2-spheres, it requires non-perturbative computation in a strongly coupled regime to obtain realisation of M5-brane geometries.
We solve this notorious problem by using the supersymmetric localisation method and see how the M-brane geometries are successfully obtained.
Intriguingly, this result gives us a consistent picture of how the gravity-side spacetime in the gauge/gravity correspondence emerges from the matrix model. |
| Date: | Tue, 03.11.2020 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | https://moodle.univie.ac.at/mod/bigbluebuttonbn/guestlink.php?gid=x8o6ILSKJuC9 |
| Contact: | Thorsten Schimannek |
| Smoothing and Flattening the Universe |
| Speaker: | Paul Steinhardt (Princeton U.) |
| Abstract: | The most salient feature of the observable universe is that it is homogeneous and spatially flat on large scales. This talk will argue why this may only be explained by replacing the big bang with a big bounce preceded by a period of slow contraction, a conclusion which has profound implications for cosmology and fundamental physics. |
| Date: | Thu, 05.11.2020 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | https://tuwien.zoom.us/j/95482849369?pwd=SkU2WU5hMVJBQWsyVlFXRlRvQlIvdz09 |
| Contact: | Laura Donnay, Niccolo Cribiori, David Andriot |
| On the structure and strength of singularities: Inextendibility results for Lorentzian manifolds |
| Speaker: | Jan Sbierski (Oxford) |
| Abstract: | Given a solution of the Einstein equations a fundamental question is whether one can extend the solution or whether the solution is maximal. If the solution is inextendible in a certain regularity class due to the geometry becoming singular, a further question is whether the strength of the singularity is such that it terminates classical time-evolution.
|
| Date: | Thu, 05.11.2020 |
| Time: | 17:00 |
| Duration: | 60 min |
| Location: | ZOOM https://zoom.us/j/4200372900?pwd=c01vb0FNRU94V0JVdWlnaDE0eUwwQT09 |
| Contact: | Piotr Chrusciel, David Fajman |
| Wave chaos as a source of exponentially fast decoherence in BECs |
| Speaker: | Iva Brezinova (TU Wien) |
| Abstract: | A Bose-Einstein condensate initially trapped in a harmonic potential and then released to expand in an external potential landscape constitutes a paradigmatic example of non-equilibrium quantum matter well controlled experimentally. The theoretical understand of such a system poses a huge challenge as one has to deal with an interacting time-dependent quantum many-body system beyond linear response. The simplest description resorts to the mean-field approximation within the Gross-Pitaevskii equation (GPE), which is a non-linear partial differential equation. In the talk, I will show that the GPE may exhibit wave chaos whose defining property is the exponential separation in Hilbert space, very much in the spirit of classical chaos and the exponential separation in phase space. This process is associated with a positive Lyapunov exponent. Now the question arises, whether this Lyapunov exp |
| Date: | Fri, 06.11.2020 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | Hörsaal ATI |
| Contact: | Jörg Schmiedmayer |
|