|
Calendar of Physics Talks Vienna
| Quantum gravity at the corner |
| Speaker: | Laurent Freidel (Perimeter Institute for Theoretical Physics) |
| Abstract: | In this talk, I will present a new perspective on the non-perturbative
quantization of gravity based on the concept of corner symmetries associated with local subregions.
After introducing the corner algebra for various formulations of general relativity, I will illustrate its physical content in 4d metric and tetrad gravity. I will also present the formalism of edge modes, whose role is to restore gauge-invariance at boundaries while preserving non-trivial charges. If time permits, I'll show our recent progress on the representation theory of these algebras. I will also describe the relationship that these results entertain with standard loop gravity, asymptotic quantization, and the concept of holography. |
| Date: | Tue, 08.12.2020 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Online https://moodle.univie.ac.at/mod/bigbluebuttonbn/guestlink.php?gid=x8o6ILSKJuC9 |
| Contact: | Céline Zwikel |
| Investigation of stationary n-black-hole configurations with soliton methods |
| Speaker: | Joerg Hennig (Otago) |
| Abstract: | An intriguing open problem in general relativity is the question as to whether stationary equilibrium configurations with clearly separated bodies can exist.Due to the nonlinear effect of the spin-spin repulsion of rotating objects and perhaps by considering charged objects with an additional electromagnetic repulsion,it remains a possibility that such unusual configurations do exist.An important example of an n-body system is a(hypothetical)equilibrium configuration with n aligned rotating and possibly charged black holes. By studying the linear matrix problem that is equivalent to the Einstein(-Maxwell)equations for axixymmetric and stationary(electro)vacuum spacetimes we obtain the most general form of the boundary data on the symmetry axis in terms of a finite number of parameters.This will be illustrated with the simplest case of one black hole in vacuum and we briefly discuss how.. |
| Date: | Thu, 10.12.2020 |
| Time: | 10:00 |
| Duration: | 60 min |
| Location: | ZOOM https://zoom.us/j/92376135485?pwd=LzlUemhvcU5rL0hhZGxPOUVieDgxZz09 |
| Contact: | Piotr Chrusciel, David Fajman |
| Quantum entanglement for precision sensing with atoms in cavities |
| Speaker: | Onur Hosten (Institute of Science and Technology, Austria) |
| Abstract: | Recent advances in the level of precision in controlling atomic and optical systems have enabled the routine generation of quantum entanglement for sensing applications. In the first part of the talk I will focus on the properties, generation and usage of a particular set of entangled states called spin squeezed states, focusing on our past implementations in a cavity QED system. I will also outline our current efforts of developing a squeezed-state atom interferometer.
In the second (shorter) part of the talk I will describe some new results from our lab, demonstrating a novel method of laser frequency stabilization using an optical cavity – squash lock – which is at the brink of performing ‘better’ than any existing cavity locking method.
|
| Date: | Fri, 11.12.2020 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | on-line |
| Contact: | Thorsten Schumm |
|