Articles liés à COSMOLOGY AND UNIFIED DARK MATTER: The Chaplygin gas...

COSMOLOGY AND UNIFIED DARK MATTER: The Chaplygin gas and beyond - Couverture souple

PIATTELLA, OLIVER

 
9783844388428: COSMOLOGY AND UNIFIED DARK MATTER: The Chaplygin gas and beyond
Couverture souple
ISBN 10 : 3844388427 ISBN 13 : 9783844388428
Editeur : LAP LAMBERT Academic Publishing, 2011

Synopsis

Unified Dark Matter models aim to describe thedynamical properties of Dark Matter and Dark Energyas different aspects of the same entity which is, inthe simplest case, embodied in a perfect barotropicfluid.Such models, though successful in passingobservational tests on the expansion rate of theUniverse, may present drawbacks in their perturbativestability. Indeed, to be in agreement withobservation, they must possess a sufficiently smallspeed of sound. In this thesis, two counterexamples to this generalconclusion are put forward. First, addressing the generalised Chaplygin gas, onefinds strong hints on the viability of the model alsowhen its asymptotic speed of sound is sufficiently large.Second, a new class of Unified Dark Matter models isintroduced. They are characterised by a fasttransition from a matter-dominated era to a phasewith constant negative pressure. It turns out that, if the transition is fast enough,these models may predict a satisfactory structureformation process and cosmic background radiationanisotropies pattern.

Les informations fournies dans la section « Synopsis » peuvent faire référence à une autre édition de ce titre.

Présentation de l'éditeur

Unified Dark Matter models aim to describe thedynamical properties of Dark Matter and Dark Energyas different aspects of the same entity which is, inthe simplest case, embodied in a perfect barotropicfluid.Such models, though successful in passingobservational tests on the expansion rate of theUniverse, may present drawbacks in their perturbativestability. Indeed, to be in agreement withobservation, they must possess a sufficiently smallspeed of sound. In this thesis, two counterexamples to this generalconclusion are put forward. First, addressing the generalised Chaplygin gas, onefinds strong hints on the viability of the model alsowhen its asymptotic speed of sound is sufficiently large.Second, a new class of Unified Dark Matter models isintroduced. They are characterised by a fasttransition from a matter-dominated era to a phasewith constant negative pressure. It turns out that, if the transition is fast enough,these models may predict a satisfactory structureformation process and cosmic background radiationanisotropies pattern.

Biographie de l'auteur

Oliver F. Piattella is visiting professor of the Cosmology groupin the department of Physics at the Federal University ofEspírito Santo (Vitória, Brazil). He received his Ph.D. inJanuary 2010 from Insubria University (Como, Italy). His mainresearch interests are in Cosmology, with particular focus onDark Energy and Dark Matter investigation.

Les informations fournies dans la section « A propos du livre » peuvent faire référence à une autre édition de ce titre.

Éditeur
LAP LAMBERT Academic Publishing
Date d'édition
2011
Langue
anglais
ISBN 10 
3844388427
ISBN 13 
9783844388428
Reliure
Broché
Nombre de pages
108
Coordonnées du fabricant
non disponible
Personne responsable
KreGa Onlinehandel GmbH
4950000000000
info@krega-onlinehandel.de

Birkenweg 31
Brakel
33034
Allemagne