Status: Bibliographieeintrag
Standort: ---
Exemplare:
---
| Online-Ressource |
Verfasst von: | Sawicki, Ignacy [VerfasserIn]  |
| Amendola, Luca [VerfasserIn]  |
Titel: | Consistent perturbations in an imperfect fluid |
Verf.angabe: | Ignacy Sawicki, Ippocratis D. Saltas, Luca Amendola and Martin Kunz |
Jahr: | 2012 |
Umfang: | 55 S. |
Fussnoten: | Gesehen am 13.11.2017 |
Titel Quelle: | Enthalten in: De.arxiv.org |
Ort Quelle: | [S.l.] : Arxiv.org, 1991 |
Jahr Quelle: | 2012 |
Band/Heft Quelle: | (2012) Artikel-Nummer 1208.4855, 55 Seiten |
Abstract: | We present a new prescription for analysing cosmological perturbations in a more-general class of scalar-field dark-energy models where the energy-momentum tensor has an imperfect-fluid form. This class includes Brans-Dicke models, f(R) gravity, theories with kinetic gravity braiding and generalised galileons. We employ the intuitive language of fluids, allowing us to explicitly maintain a dependence on physical and potentially measurable properties. We demonstrate that hydrodynamics is not always a valid description for describing cosmological perturbations in general scalar-field theories and present a consistent alternative that nonetheless utilises the fluid language. We apply this approach explicitly to a worked example: k-essence non-minimally coupled to gravity. This is the simplest case which captures the essential new features of these imperfect-fluid models. We demonstrate the generic existence of a new scale separating regimes where the fluid is perfect and imperfect. We obtain the equations for the evolution of dark-energy density perturbations in both these regimes. The model also features two other known scales: the Compton scale related to the breaking of shift symmetry and the Jeans scale which we show is determined by the speed of propagation of small scalar-field perturbations, i.e. causality, as opposed to the frequently used definition of the ratio of the pressure and energy-density perturbations. |
URL: | Bitte beachten Sie: Dies ist ein Bibliographieeintrag. Ein Volltextzugriff für Mitglieder der Universität besteht hier nur, falls für die entsprechende Zeitschrift/den entsprechenden Sammelband ein Abonnement besteht oder es sich um einen OpenAccess-Titel handelt.
kostenfrei: Volltext: http://arxiv.org/abs/1208.4855 |
Datenträger: | Online-Ressource |
Sprache: | eng |
Sach-SW: | Astrophysics - Cosmology and Nongalactic Astrophysics |
| High Energy Physics - Theory |
| General Relativity and Quantum Cosmology |
K10plus-PPN: | 1565257022 |
Verknüpfungen: | → Sammelwerk |
Consistent perturbations in an imperfect fluid / Sawicki, Ignacy [VerfasserIn]; 2012 (Online-Ressource)
68189099