Vienna-Theory-Lunch-Club--Seminar
WS08/09
by Daniel Grumiller & Beatrix Hiesmayr & Maximilian Attems
Di 12:30-13:30
abwechselnd auf der
TU Wien (E136, 10. Stock (gelb))
oder der
Uni Wien (Boltzmanngasse 5, 5.Stock, gr. Seminarraum)
Vienna-Theory-Lunch-Club--Seminar
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| Idee/Idea: | Wie auf vielen Elite Unis praktiziert, wollen wir ein Lunch-Seminar etablieren, das aktuelle Themen der Theoretischen Physik, die auf unseren Unis von DiplomandInnen, DoktorandInnen und Postdocs behandelt werden, aufgreifen. Das Niveau soll so sein, dass jeder Student und jede Studentin am Ende des Studiums dem Vortrag folgen kann! Die Vortragenden werden auch ermutigt, keinen "perfekten" Vortrag zu halten, sondern haupsächlich zu motivieren, warum sie dieses Thema gewählt haben, und dabei dürfen auch durchaus offene Fragen und Probleme behandelt werden. Damit es zu praktisch keinen "Zeitverlust" kommt, wird gratis ein Mittagessen (Pizza,...) zur Verfügung gestellt. |
We want to establish a Graduate Student Lunch Club as praticed at other institutions like MIT. The seminars are designed for graduate students and should be accesible to all students. Students before their Diploma are particularly encouraged to attend so that they may learn about research begin performed on both universities. Speakers are encouraged to focus also on their motivation why they chose this particular topic and raise open questions. In order to avoid any "loss of time" we provide a free lunch (pizza,...). |
Wie kann ich teilnehmen?/ How can I join? |
Einfach erscheinen! Falls man per Email informiert werden möchte, besuche die Seite Mailinglist oder Mail an Beatrix.Hiesmayr et univie.ac.at oder an grumil et hep.itp.tuwien.ac.at |
Just attend! To receive infos per email got to Mailinglist or drop an email to Beatrix.Hiesmayr et univie.ac.at or grumil et hep.itp.tuwien.ac.at |
7. Oktober 2008 TU Wien |
Gerd Ch. Krizek (Uni Wien) |
Gedanken Experiments for Quantum Mechanics and Gravitation Quantum mechanics and the general theory of relativity are the pillars of
modern physics and both nearly 100 years old. But it is still one of the
biggest challenges to unify them. We will not give an answer to problems of
the unification, but want to give an insight in problems that occur when
these models overlap. We will formulate three Gedankenexperiments in which
gravity and quantum mechanics and alternative models of quantum mechanics
will play a role to give a better understanding on the problems in this
complex field.
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14. Oktober 2008 Uni Wien |
Niklas Johansson (Uppsala University) |
Recent developments in 3 d gravity Gravity in three dimensions strikes a balance between models that are tractable and models that are relevant. It may exhibit black hole solutions, graviton modes and asymptotically Anti-deSitter solutions. There have been great efforts in trying to quantize 3D gravity, but the results remain unsatisfactory. In this talk we review a recent approach to 3D gravity called "chiral gravity". This model has peculiar features giving some hope that it is particularly simple to quantize. However, there has been a sometimes heated debate regarding the stability of the model. We explain why, and give an updated status report. |
21. Oktober 2008 TU Wien |
Nicolai Friis (Uni Wien) |
Relativistic effects in quantum entanglement Entanglement of quantum systems has proven to be a vital resource in information processing protocols, such as quantum teleportation and quantum cryptography, and the investigation of fundamental properties of nature via Bell's theorem. Much effort has therefore been put into describing and quantifying entanglement and the mechanism that lead to it's diminishment. Thus the next logical step is to continue the analysis in a relativist setup. We will discuss the effect of Lorentz transformations on quantum systems in form of the so called Wigner rotations and their influence on entanglement. We will present the possibilities and difficulties arising from this relativistic description. |
28. Oktober 2008 Uni Wien |
Daniel Blaschke (TU Wien) |
Towards renormalizable models for gauge fields in non-commutative space
When trying to construct a quantum field theory on non-commutative space-time,
e.g. by employing the so-called Groenewold-Moyal star product, one inevitably
runs into the infamous UV/IR mixing problem where new kinds of non-local IR
divergences prevent the model from being renormalizable. In fact, so far only
some modified scalar field theories on Euclidean non-commutative spaces have
been found to be renormalizable by successfully circumventing problems due to
UV/IR mixing. In this talk I give an introduction to this interesting field of
research and present a promising candidate for a renormalizable non-commutative
gauge theory.
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4. November 2008 TU Wien |
Robert Schoefbeck (HEPHY) |
Early SUSY searches at CMS
This is not going to be a purely experimental talk. I will
review the basic motivation for supersymmetry and its phenomenological
implications. We will discuss the current situation in experiment
and the theorists hope for future findings at the LHC in the
main SUSY channels. This talk is intended as a teaser for the exciting
physics ahead, and I try to shed light on some aspects of the most
interesting correlations among theory, phenomenology and the every-day
work of the particle physicist.
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11. November 2008 Uni Wien |
Rene Meyer (MPI Munich) |
The D3-D7 model of AdS/CFT with Flavour
I will give a pedagogical introduction into the D3-D7 model of holographic
(N=2 supersymmetric) flavour physics, as well as talk about recent
results concerning the behaviour of this system in the presence of
external electric and magnetic fields.
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18. November 2008 TU Wien |
Philipp Krammer (Uni Wien) |
Geometric entanglement witnesses
A challenge in quantum information theory is the detection of entangled states on a finite dimensional Hilbert space. Useful tools for this purpose are entanglement witnesses; they provide a geometrically intuitive method to detect entanglement. I will explain the concept of entanglement witnesses and how to combine it with the notion of Bloch decompositions. Geometric entanglement witnesses are a simple example for a geometrical construction of witnesses. I will show how to use "shifts" of such witnesses in order to detect entanglement and to find the set of separable states for a convex subset of states.
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25. November 2008 Uni Wien |
Andreas Kastner (Uni Wien) |
Semileptonic Kaon decays in Chiral perturbation theory
Due to quark confinement QCD, the quantum field theory of strong
interactions, becomes non-perturbative at low energy. In order to obtain
predictions for strong processes in the energy region of confinement,
one can use a so called effective field theory. Chiral perturbation
theory (ChPT), the low-energy limit of the standard model, only makes
use of the symmetries of the QCD Lagrangian and does not invoke the
dynamics of quarks and gluons. We want to show the basic properties and
problems of effective field theories by discussing the predictions of
the standard model for specific kaon decays, the K_l3 decays, in ChPT,
including isospin violating effects of strong and electromagnetic origin.
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2. Dezember 2008 TU Wien |
Florian Aigner (TU Wien) |
Coherent scattering of fast atoms at surfaces
Diffraction of particles scattered at surfaces was among the key experiments establishing the quantum wave nature of matter. Atoms being diffracted at crystal surfaces exhibit intriguing diffraction patterns, closely related to those visible in double-slit experiments, which have been carried out using particles as heavy as fullerenes. Scattering of keV atoms at surfaces has recently been shown to be a powerful tool to investigate the structure of surfaces. Even in environments which would strongly suggest the dominance of decohering effects (hot surfaces, phonon vibrations) quantum coherent scattering patterns remain visible. This is especially remarkable, as the de Broglie wavelength of scattered atoms in the keV range is as low as a few picometers.
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9. Dezember 2008 Uni Wien |
Wolfgang Dungel (HEPHY) |
Physics analysis at Belle
The aim of physics analysis is to match the predictions of theory with experimental results.
At the collider experiment Belle in Tsukuba, Japan, the main focus lies
in the investigation of the Cabbibo-Kobayashi-Maskawa matrix, which
contains the only source of CP-violation within the standard model.
This talk aims at presenting the Belle experiment and the basic aims and
pitfalls in analyzing the data of particle physics experiments in a very
general way. Afterwards, a more detailed view of one specific analysis
will be given, which centers on the investigation of 'B0-> D* l nu' decays.
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16. Dezember 2008 TU Wien |
Narit Pidokrajt (Stockholm University) |
Black Hole Thermodynamics à la Information Geometry
In this talk we will discuss the use of information (a.k.a. Ruppeiner)
geometry to understand thermodynamics of various black holes e.g. 2D dilaton
black holes, Myers-Perry black holes in higher dimensions among others. It
has been known that the geometrical theory of thermodynamics provides an
alternative and elegant route to obtain insight into thermodynamics through
Riemannian geometry. Its power is due to the fact that the information
metric together with its associated curvature and signature encodes many
aspects of thermodynamics consistent with the known results in the
literature. Since we do not yet have a settled statistical mechanics of
black holes, the information geometry of black hole thermodynamics also
paves a road to a (possibly) new way of understanding of the microscopic
degrees of freedom of the black holes. There are many potential
applications of this geometric method as there are emerging black objects in
higher dimensions and black hole analogs which require new perspectives in
order to better understand them.
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13. Jänner 2009 Uni Wien |
Dionysis Triantafyllopoulos (ECT Trento and TU Wien) |
Parton Saturation in Quantum Chromodynamics
When we perform a series expansion in a Quantum Field Theory, large
logarithms may appear in the perturbative coefficients in certain
kinematical regions. Such a situation arises in Quantum Chromodynamics
when we consider the scattering between partons at large center of mass
energy and at a fixed momentum transfer. A resummation must be performed
and the resulting total cross section rises as a power of the energy. At
even higher energies nonlinear phenomena take place which lead to the
unitarization of the cross section and the saturation of the hadronic
wavefunction.
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20. Jänner 2009 TU Wien |
Harald Ita (UCLA) |
One-Loop Multi-Parton Amplitudes for the LHC
We discuss the computation of one-loop QCD scattering
amplitudes with BlackHat, a numerical program based on on-shell
methods. We report scaling properties with increasing numbers of
external partons and about numerical stability of the implementation.
We conclude with first results from one-loop amplitudes needed for
computing W,Z + 3 jet cross sections at the LHC to next-to-leading
order in the QCD coupling.
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27. Jänner 2009 Uni Wien |
Andres Collinucci (TU Wien) |
F-theory: Introduction and recent developments
Fourteen years ago, string theory underwent a major paradigm shift
when techniques were developed to study the theory non-
perturbatively, i.e. in its strongly coupled regime. More
specifically, the introduction of D-branes and eventually M-theory
opened up windows that relate the different versions of string
theory, in different corners of its parameter space.
A year after the idea of M-theory was conceived, Vafa developed what
can be thought of as its obscure partner, known as "F-theory".
Although it is less understood conceptually, F-theory is a more
practical tool for model building, i.e. for trying to make contact
with the standard model. Curiously, the year 2008 has seen a revival
of "F-theory", as new results have emerged in the direction of model
building.In this talk, I will give an overall rough picture of M-theory and F- theory without assuming prior knowledge of string theory. Then, as time permits, I will show an explicit F-theory toy model. Finally, I will summarize the most recent developments in this branch. |