Central European Institute for Cosmology and Fundamental Physics
 

Planned seminars

12 Dec 2017 14:00     David Svoboda,  Twisted brackets, fluxes, and deformations of para-Kahler manifolds

 

27/11/2017 -- Rachel Houtz (IFT Madrid)

Time:  14:00

Place: 226

Little Conformal Symmetry and Neutral Naturalness

Given the lack of conventional SUSY signals in the LHC data, a more complicated story may be required to explain weak scale physics. I will present a class of natural models which ensure the one-loop divergences in the Higgs mass are cancelled. The top partners are not related by an internal symmetry of the Lagrangian, but instead the symmetry relation that ensures the cancellation arises at an infrared fixed point. Such a cancellation mechanism can, a la Little Higgs models, push the scale of the new physics that completely solves the hierarchy problem up to 5-10 TeV. When embedded in a supersymmetric model, the superpartner masses provide the cutoffs for the loops, and the mechanism alleviates the stop mass dependence on the Higgs mass parameter.

  

28/11/2017 -- Sugumi Kanno (University of the Basque Country)

Time:  14:00

Place: Lecture theatre

Decoherence of Bubble Universes

In de Sitter space where the universe expands exponentially, any two of mutually separated region eventually becomes causally disconnected. This is most conveniently described by spanning open universe coordinates on two open charts in de Sitter space. Recently, Maldacena and Pimentel showed that the entanglement entropy of a free massive scalar field between two open charts is non-vanishing. This result can be thought of as showing that a pair creation of bubble universes in de Sitter space is entangled. In order to understand a process of decoherence of bubble universes, I assume there is a delta-functional wall between two open charts. This may be regarded as a model describing the pair creation of identical bubble universes separated by a bubble wall. I will discuss the effect of the bubble wall on the entanglement entropy of the free massive scalar field between two open charts in de Sitter space.


30/11/2017 -- Marc Gillioz (EPFL)

Time:  14:00

Place: 226

Sum Rules for the "c" Anomaly in 4 Dimensions

The "c" anomaly is an interesting quantity in 4-dimensional conformal field theory: it is known to qualitatively count the states of the theory. We present a method that makes this statement quantitative, using the fact that c appears as a scale anomaly in the 4-points correlator of energy-momentum tensors. Along the way, we describe how to make sense of the operator product expansion in momentum space and discuss its convergence.

  

4/12/2017 -- Ed Copeland (University of Nottingham)

Time:  14:00

Place: 226

Screening mechanisms and testing for them in cosmology and the laboratory  

We look at possible candidate screening mechanisms in particular the Symmetron and Chameleon mechanisms. We ask how can they be searched for in table top experiments and look at the possibility that the symmetron may play a role in accounting for the observed galaxy rotation curves.