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Calendar of Physics Talks Vienna
| Speaker: | Joan Simon (Edinburgh U.) |
| Abstract: | We consider the EPR=ER ideas in the context of two entangled N=4 SYM theories in the Hilbert space of half-BPS SO(4) invariant states. Even though this sector of the theory does not carry enough entropy to build a macroscopic bridge, the knowledge over the wave functions of the quantum states allows us to design quantum bridges between both N=4 SYM in specific regions of their phase spaces. Time permitting, we can comment on the relation between entanglement entropy in this sector and in optically trapped ultra-cold atomic gases. |
| Date: | Mon, 19.06.2017 |
| Time: | 11:30 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Daniel Grumiller |
| Asymptotic structure of N=2 supergravity in 3D: extended super-BMS3 and nonlinear energy bounds |
| Speaker: | Oscar Funetealbe (CECs Valdivia) |
| Abstract: | The asymptotically flat structure of N=(2,0) supergravity in three spacetime dimensions is explored. The asymptotic symmetries are found to be spanned by an extension of the super-BMS3 algebra, endowed with two independent affine u(1) currents of electric and magnetic type. These currents are associated to U(1) fields that are even and odd under parity, respectively. Remarkably, although the U(1) fields do not generate a backreaction on the metric, they give nontrivial Sugawara-like contributions to the BMS3 generators, and hence to the energy and the angular momentum. Consequently, it can be seen that the entropy of flat cosmological spacetimes endowed with U(1) fields not only depends on the mass and the angular momentum but also on the zero modes of the u(1) charges. We also show that in the case where the spin structure is chosen to be even, the energy is shown to be nonnegative, ... |
| Date: | Mon, 19.06.2017 |
| Time: | 14:30 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Daniel Grumiller |
| The dawning era of gravitational wave astronomy |
| Speaker: | Michèle Heurs (CoQuS) |
| Abstract: | The announcement of the first direct detection of gravitational waves (the merger of a binary black hole system) in February 2016 has heralded the new era of gravitational wave astronomy. It opens a new window to the universe, and will help reveal its “dark” secrets, inaccessible to astronomy in the electromagnetic spectrum and neutrino astronomy.
After an introduction to gravitational waves and their effect on space-time I will explain the principle of interferometric gravitational wave detection. I will present advanced interferometer noise-reduction techniques and detector sensitivities. Finally, I will touch upon the current status of the field, including plans for spaceborne detectors.
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| Date: | Mon, 19.06.2017 |
| Time: | 17:00 |
| Duration: | 60 min |
| Location: | Atominstitut, Stadionallee 2, 1020 Vienna |
| Contact: | CoQuS-Team |
| Lattice Simulations of 10d Yang-Mills in Toroidal Compatification |
| Speaker: | Paul Romatschke (Colorado U.) |
| Abstract: | Toroidally compactified Yang-Mills theory on the lattice is studied by using the Hybrid Monte Carlo algorithm. When the compact dimensions are small, the theory naturally reduces to Yang-Mills with scalars. I'll compare YM lattice simulations for pure gauge theory to analytic results in 0+1 and SYM simulations in 1+1d. I'll close by talking about the prospects of performing real-time quantum black hole simulations from the gauge theory side. |
| Date: | Tue, 20.06.2017 |
| Time: | 10:00 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Daniel Grumiller |
| Gravity in the quantum lab |
| Speaker: | Ivette Fuentes Guridi (OeAW Vienna) |
| Abstract: | Quantum experiments are reaching relativistic regimes. Quantum communication protocols have been demonstrated at long lenghts scales and experiments are underway to distribute entanglement between Earth and Satellite-based links. At these regimes the Global Positioning System requieres relativistic corrections. Therefore, it is necessary to understand how does motion and gravity will affect long-range quantum experiments. Interestingly, relativistic effects can also be observed at small lengths scales. Some effects have been demonstrated in superconducting circuits involving boundary conditions moving at relativistic speeds and quantum clocks have been used to measure time dilation in table-top experiments. In this talk I will present a formalism for the study of gravitational effects on quantum technologies. This formalism is also applicable in the development of new quantum techn. ... |
| Date: | Tue, 20.06.2017 |
| Time: | 14:30 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Markus Aspelmeyer and Caslav Brukner and Daniel Grumiller |
| PhysikerInnen im Bereich Risiko und Finanzen – Vorstellung d-fine |
| Speaker: | Beate Solleder (d-fine Austria GmbH, Wien) |
| Abstract: | What will I do after finishing my studies in Physics? Stay in Physics or do something else? But what?
That’s what I asked myself some years ago, deciding finally to go for “something else”. I learned that there are many interesting answers available to the last question above. Thus in this talk, I will give students who are asking themselves the same questions, the opportunity to get some insights into possible career paths outside of academia. My path led to d-fine, one of the leading European consulting firms in the area of financial and regulatory risk management. I will give an overview of who we are and what we do. One of the reasons I joined d-fine three years ago was, that we are a team of about 600 professionals with strong quantitative background, 50% of which are physicists. An essential part of the seminar will be reserved for questions and discussion, e.g. about why we think |
| Date: | Tue, 20.06.2017 |
| Time: | 16:00 |
| Location: | Technische Universität Wien, Institut für Angewandte Physik, E134 yellow tower „B“, 5th floor, Sem.R. DB gelb 05 B (room number DB05L03), 1040 Wien, Wiedner Hauptstraße 8-10 |
| Contact: | Univ.Prof.Dr. Friedrich Aumayr |
| Dark Matter Decay? Possible Observational Tests - According to Conformal Cyclic Cosmology |
| Speaker: | Roger Penrose (Oxford U.) |
| Abstract: | In the cosmological scheme of conformal cyclic cosmology (CCC), the equations governing the crossover form each aeon to the next demand the creation of a dominant new scalar material that is postulated to be dark matter. In order that this material does not build up from aeon to aeon, it is taken to decay away completely over the history of the aeon. The dark matter particles (erebons) would be expected to behave as essentially classical particles of around a Planck mass, interacting only gravitationally, and their decay would be mainly responsible for the (~scale invariant) temperature fluctuations in the CMB of the succeeding aeon. In our own aeon, erebon decay ought to be detectable as impulsive events observable by gravitational wave detectors. |
| Date: | Tue, 20.06.2017 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Markus Aspelmeyer and Caslav Brukner and Daniel Grumiller |
| B → ππ Form Factors at Large Dipion Mass |
| Speaker: | Thorsten Feldmann (Univ. Siegen) |
| Abstract: | im Rahmen des Teilchenphysikseminars |
| Date: | Tue, 20.06.2017 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, H. Neufeld |
| The quantum measure - and how to measure it |
| Speaker: | Rafael Sorkin (PI) |
| Abstract: | When utilized appropriately, the path-integral offers an alternative to the ordinary quantum formalism of state-vectors, selfadjoint operators, and external observers - an alternative that seems closer to the underlying reality and more in tune with quantum gravity. The basic dynamical relationships are then expressed, not by a propagator, but by the *quantum measure*, a set-function mu that assigns to every (suitably regular) set E of histories its generalized measure mu(E). (The idea is that mu is to quantum mechanics what Wiener-measure is to Brownian motion.) Except in special cases, mu(E) cannot be interpreted as a probability, as it is neither additive nor bounded above by unity. Nor, in general, can it be interpreted as the expectation value of a projection operator (or POVM). Nevertheless, I will describe how one can ascertain mu(E) experimentally for any specified E, by means of |
| Date: | Wed, 21.06.2017 |
| Time: | 11:30 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Markus Aspelmeyer and Caslav Brukner and Daniel Grumiller |
| Aspects of Holography in Two-Dimensional Dilaton Gravity |
| Speaker: | Jakob Salzer (TU Wien) |
| Abstract: | The simplest toy models for classical and quantum gravity that can have black hole solutions are two-dimensional. Yet, two-dimensional Einstein gravity is not among them: in two dimensions the Einstein tensor vanishes identically. Dilaton gravity, however, is a consistent theory of gravity in two dimensions. However, holography in two dimensions appears to be, in some aspects, more subtle than its higher-dimensional relative. Following an introduction to two-dimensional dilaton gravity and its formulation as a Poisson sigma model, I will describe the holographic renormalization of different dilaton gravity models and discuss different set-ups for AdS2 holography. |
| Date: | Wed, 21.06.2017 |
| Time: | 14:30 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Daniel Grumiller |
| Symmetry protected entanglement between gravity and matter |
| Speaker: | Nikola Paunkovic (CFTP Lisbon) |
| Abstract: | We show that gravity and matter fields are generically entangled, as a consequence of the local Poincare symmetry. First, within the covariant framework, we show explicitly that the Hartle-Hawking state in the Regge model of quantum gravity is necessarily entangled. Also, we present a general argument, applicable to any particular theory of quantum gravity with matter, by performing the analysis in the abstract nonperturbative canonical framework, demonstrating the nonseparability of the scalar constraint, thus promoting the entangled states as the physical ones. Our result is potentially relevant for the quantum-to-classical transition, taken within the framework of the decoherence programme: due to the symmetry requirements, the matter does not decohere, it is by default decohered by gravity. Generically, entanglement is a consequence of interaction. This new entanglement could potenti |
| Date: | Wed, 21.06.2017 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Markus Aspelmeyer and Caslav Brukner and Daniel Grumiller |
| About the influence of gravitational waves on circular moving topological solitons with long range interaction |
| Speaker: | Manfried Faber (Vienna) |
| Abstract: | The majority of physicists wants to quantize gravity. To unify gravity and particle physics there is another possibility, a geometrization of particle physics. We will present some ideas in this direction. I will give some short overview on a simple model of rotating Dreibeins. This model has four types of stable topological solitons differing in two topological quantum numbers which we identify with electric charge and spin. The vacuum has a two-dimensional degeneracy leading to two types of massless excitations, characterised by a topological quantum number which could have a physical equivalent in the photon number. Inspired by the silicon oil drop experiment of Yves Couder we follow the idea that a subquantum medium could influence classical solitons on their path and lead to quantum mechanics. Under this point of view we investigate the influence of a gravitational wave . . . . |
| Date: | Thu, 22.06.2017 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien |
| Contact: | P.T. Chrusciel |
| Probing quantum fields and their fluctutions with a quantum simulator |
| Speaker: | Jörg Schmiedmayer (TU Wien) |
| Date: | Thu, 22.06.2017 |
| Time: | 14:30 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Markus Aspelmeyer and Caslav Brukner and Daniel Grumiller |
| SYK, 2D CFT and Gravitational Scattering |
| Speaker: | Herman Verlinde (Princeton U.) |
| Date: | Thu, 22.06.2017 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Markus Aspelmeyer and Caslav Brukner and Daniel Grumiller |
| Jet Targets... more than only a breath of nothing |
| Speaker: | Prof. Dr. Alfons Khoukaz (Institut für Kernphysik, Westfälische Wilhelms-Universität Münster) |
| Abstract: | Jet beams are widely used as targets in many fields of physics. Prominent examples are, e.g., scattering experiments at particle accelerators or at terawatt laser facilities where pure and windowless targets of adjustable thickness are required in vacuum. Depending on the specific experimental situation, different types of targets such as gas-jets or cluster-jets can be utilized in order to meet the demanded features. However, in recent years new experimental challenges came up which require to significantly improve the performance of existing target technologies, as well as to develop new target production and monitoring techniques. Inspired by this, new research projects were initiated with the focus on the optimized generation and preparation of gas-jet, cluster-jet, and pellet target beams. An overview of these types of targets will be given and recent achievements will be presented. |
| Date: | Thu, 22.06.2017 |
| Time: | 17:00 |
| Duration: | 60 min |
| Location: | Stefan-Meyer-Institut, Boltzmanngasse 3, 1090 Wien, Seminarraum 3-2-08 (2. Stock) |
| Contact: | Prof. Dr. Eberhard Widmann, Dr. Martin Simon |
| Feynman diagrams and gravity join forces to crack the QGP |
| Speaker: | Ayan Mukhopadhyay (TU Wien) |
| Abstract: | In many systems such as the quark-gluon plasma (QGP), it is necessary to combine perturbative and non-perturbative degrees of freedom to describe collective behavior. Multiple energy scales are typically involved in processes such as thermalization. Semi-holography is a proposal to build effective theories of these systems in which it is postulated that non-perturbative strongly coupled physics is described via holographic duality by an appropriate classical gravity theory that should be constructed in order to cure absence of Borel resummability of perturbative dynamics. After briefly discussing the general formulation, we will describe the phenomenological construction of the semi-holographic model for QGP where we have recently succeeded in combining the kinetic theory of hard gluons with the strongly coupled fluid description of the soft sector. Our latest results demonstrate ... |
| Date: | Fri, 23.06.2017 |
| Time: | 10:00 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Daniel Grumiller |
| Weyl anomalies and brane charges |
| Speaker: | Daniel Plencner (LPTHE Paris) |
| Abstract: | I will discuss Weyl anomalies of 2d N=(2,2) superconformal field theories with exactly marginal deformations. Extending recent work by Gomis et al, I will present the super-Weyl anomaly in the presence of boundaries, and will show it is determined by the holomorphic central charge of the boundary/D-brane. A corollary is a novel proof that the hemisphere partition function computes the D-brane central charge. The talk is based on arXiv:1612.06386 with C. Bachas. |
| Date: | Fri, 23.06.2017 |
| Time: | 11:00 |
| Duration: | 60 min |
| Location: | Mathematik Uni Wien, Besprechungszimmer 2 (2. Stock) |
| Contact: | Nils Carqueville |
| Parity anomaly in four dimensions |
| Speaker: | Dmitri Vassilevich (ABC Federal U. ) |
| Abstract: | It is known for more than 30 years that quantum Dirac fermions in odd dimensional spaces possess the so called parity anomaly related to the spectral asymmentry of the Dirac operator. As a result, the Chern-Simons action with the level k=1/2 is induced in 3D. We have studied Dirac fermions on four-dimensional manifolds with with boundaries and demonstrated that a similar phenomenon take place: spectral assymetry of the Dirac operator leads to a boundary Chern-Simons term. We found a somewhat unusual Chern-Simons level k=1/4, which is however consistent with the counting of boudnary degrees of freedom. Applications to the condensed matter physics and holography will be briefly discussed. |
| Date: | Fri, 23.06.2017 |
| Time: | 11:30 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Daniel Grumiller |
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