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Théorie

Fake hair for black holes

Orateur: 
Christos Charmousis
Home Institute: 
LPT, Université Paris 11
Lieu: 
483A Malevitch
Horaire: 
Tuesday, 8. April 2014 - 14:00

We will review modified gravity theories and in particular scalar
tensor theories, the mildest of modifications, where
we have an additional interacting scalar field coupling to the metric

Holographic RG flows and Quantum Effective Actions

Orateur: 
Francesco Nitti
Home Institute: 
APC
Lieu: 
483 A - Malevitch
Horaire: 
Tuesday, 18. March 2014 - 14:00

 

Spectral distortions in the cosmic microwave background polarization

Orateur: 
Sébastien Renaux-Petel
Lieu: 
483A Malevitch
Horaire: 
Tuesday, 25. March 2014 - 14:00

Deviations of the cosmic microwave background (CMB) spectrum from the one of a blackbody, so-called spectral distortions, have recently emerged as a powerful probe of many physical phenomena, ranging from inflation to dark matter and reionization. However, most studies so far have concentrated on the distortions of the monopole of the CMB intensity, while future missions will characterize the spectrum of its anisotropies, both in intensity and in polarization.

The confining trailing string

Orateur: 
Liuba Mazzanti
Lieu: 
483A Malevitch
Horaire: 
Tuesday, 11. February 2014 - 14:00

We extend the holographic trailing string picture of a heavy quark diffusing through the plasma to the case of a bulk geometry dual to a confining gauge theory. We compute the classical trailing confining string solution for a static as well as a uniformly moving quark. The trailing string is infinitely extended and approaches a confining horizon, situated at a critical value of the radial coordinate, along one of the space-time directions, breaking boundary rotational invariance.

Inflation, BICEP2, and an interesting discrepancy with Planck

Orateur: 
Lorenzo Sorbo
Lieu: 
483A Malevitch
Horaire: 
Tuesday, 1. April 2014 - 14:00

 

An introduction to the non perturbative renormalization group: method and some applications in statistical mechanics

Orateur: 
Bertrand Delamotte
Home Institute: 
LPTMC, Université Pierre et Marie Curie
Lieu: 
483 A - Malevitch
Horaire: 
Tuesday, 25. February 2014 - 14:00

An introduction to the modern version of Wilson's renormalization group will be given together with the two nonperturbative approximation schemes that have effectively been implemented (the derivative expansion and the Blaizot-Mendez-Wschebor scheme). The O(N) scalar models will be our favourite playground. Then, some results obtained in out of equilibrium statistical mechanics will be presented showing that fully nonperturbative physics can be captured by the nonperturbative renormalization group.

Fundamental Physics and Nuclear Structure

Orateur: 
Jonathan Engel
Home Institute: 
North Carolina State University
Lieu: 
646 A-Mondrian
Horaire: 
Tuesday, 11. March 2014 - 14:00

Much of the fundamental physics we have learned about in recent years was uncovered in low-energy experiments.  More low-energy experiments are in progress and many require that nuclear effects be untangled from the fundamental physics we are trying to probe.  I review the issue and attempts to understand the relevant nuclear physics in three kinds of experimental searches: for neutrinoless double beta decay,  for new sources of CP violation through nonzero atomic electric dipole moments, and for  dark matter particles through scattering from ordinary matter.

Charged Chern-Simons AdS black holes

Orateur: 
Nelson Merino
Lieu: 
483A Malevitch
Horaire: 
Tuesday, 18. February 2014 - 14:00

We found the most general spherically symmetric, static black hole solution for Chern-Simons gravity based on a simple extension of the AdS algebra, that is, AdS x U(1). The corresponding gauge connection contains gravitational fields describing a Riemann-Cartan manifold with electromagnetic matter field. When the electromagnetic field and some components of the torsion are switched off, solution reproduces the known ones found in the literature. For other choices of the torsion components, our solution is physically different from the already known ones.

Cubic interactions and Symmetries of Higher-spin field theories

Orateur: 
Euihun Joung
Home Institute: 
APC
Lieu: 
483A Malevitch
Horaire: 
Tuesday, 4. February 2014 - 14:00
The deformations of higher-spin symmetries induced by cubic interactions of symmetric massless bosonic fields will be analyzed within the metric-like formalism. In particular, I will identify a class of couplings which leave the gauge algebra Abelian but deform one (out of three) gauge transformation, and another class of couplings which deform all three gauge transformations in (A)dS but only two in the flat-space limit. The former class is related to higher-spin algebra multiplets (representations of the global algebra).

Localized features in the primordial spectra from heavy physics

Orateur: 
Ryo Saito
Lieu: 
483A Malevitch
Horaire: 
Tuesday, 14. January 2014 - 14:00

Primordial density fluctuations provide one of a few ways to probe the high energy physics behind inflation. In this talk, we discuss the possibility that we could obtain some hints of the heavy physics during inflation by analyzing local features in the spectra of the primordial fluctuations.

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