LOBED · Lorentz violatining brane-world models and their cosmological relevance
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2006-11-01 → 2008-10-31
- EU contribution
- €151,981
- Participants
- 1
- Scheme
- EIF
Lines connect the coordinator with its partners.
Results in brief
Final Activity Report Summary - LoBED (Lorentz Violatining Brane-World Models and their Cosmological Relevance)
Within the general context of high energy physics, this research work focussed on techniques and ideas based on the existence of extra dimensions of space, beyond the usual three dimensions which we observe in everyday life. Two main motivations for this idea exist in particle physics and both of them were investigated within this project: 1. the use of extra dimensions to build models beyond the standard model of particle physics 2. the concept of holography, which used curved space-times extra dimensions to describe the physics of strongly coupled quantum field theories. In the context of brane-world models, we studied the existence and lifetime of metastable, i.e. unstable but long-lived, vacua and examined how these could be used to construct models of supersymmetry breaking. In order to exploit the second motivation, we utilised the best known and understood holographic setups. We developed a class of phenomenological holographic models that captured the salient features of real-world quantum chromo-dynamics (QCD), e.g. running of the coupling and colour confinement. Furthermore, we showed that the thermodynamics of these models were also very similar to those of finite temperature QCD. This could in principle lead to an accurate quantitative description of the hydrodynamics of the quark-gluon plasma phase that is created in heavy-ion collision experiments. Such experiments were under way at the relativistic heavy ion collider (RHIC), as well as planned at the large hadron collider (LHC).
Data: CORDIS, © European Union
Project objective
In recent years, observational evidence for an accelerated expansion of the Universe has triggered investigation of non-conventional cosmological models. At the same time, the precision reached in the observation of the Cosmic Microwave Background Radiation (CMBR) offers the possibility of detecting deviations from the predictions of ordinary models of the Early Universe.In particular, models in which the observed Universe is a four-dimensional surface in a higher dimensional space-time (so called Brane-World models) offer a wide range of possibly interesting new phenomenology. In this context, we investigate scenarios in which Lorentz invariance is violated by the geometry of the higher dimensional space-time. We will study the consequences of this fact on both the early- and late-time cosmological evolution. In particular, we will address the questions whether these type of constructions can accommodate the possibility of a late-time accelerated expansion, whether there can be distinctive signatures of this type of Lorentz-violation in the spectrum of the CMBR, and whether these models provide new string-theoretical realizations of Inflation.We will also explore the consequences of breaking Lorentz invariance from an effective field theoretical point of view. We will address these questions in two kinds of models with different nature of Lorentz violation: in the first class of models Lorentz invariance is broken by the bulk metric; in the second, the bulk metric is Lorentz-invariant but the boundary conditions are not. Within the latter class of models we will focus our study on a recently found time-dependent string theoretical construction. This model is particularly promising for realising inflationary cosmology in string theory.
Original text from CORDIS.
Participants
- CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE · PARISCoordinatorFrance
Links
Data: CORDIS, © European Union