Cosmology with matter diffusion
Artikel i vetenskaplig tidskrift, 2013

We construct a viable cosmological model based on velocity diffusion of matter particles. In order to ensure the conservation of the total energy- momentum tensor in the presence of diffusion, we include a cosmological scalar field phi which we identify with the dark energy component of the universe. The model is characterized by only one new degree of freedom, the diffusion parameter sigma. The standard Lambda CDM model can be recovered by setting sigma = 0. If diffusion takes place (sigma > 0) the dynamics of the matter and of the dark energy fields are coupled. We argue that the existence of a diffusion mechanism in the universe may serve as a theoretical motivation for interacting models. We constrain the background dynamics of the diffusion model with Supernovae, H(z) and BAO data. We also perform a perturbative analysis of this model in order to understand structure formation in the universe. We calculate the impact of diffusion both on the CMB spectrum, with particular attention to the integrated Sachs-Wolfe signal, and on the matter power spectrum P(k). The latter analysis places strong constraints on the magnitude of the diffusion mechanism but does not rule out the model.

cosmological parameters from LSS

DARK-ENERGY

EQUATION

dark energy theory

CONSEQUENCES

HUBBLE

DIGITAL SKY SURVEY

DISTANCE

PERTURBATIONS

CONSTANT

power spectrum

dark matter theory

BARYON ACOUSTIC-OSCILLATIONS

CONSTRAINTS

MODELS

Författare

Simone Calogero

Chalmers, Matematiska vetenskaper, Matematik

Göteborgs universitet

H. Velten

Universidade Federal do Espirito Santo

Journal of Cosmology and Astroparticle Physics

1475-7516 (ISSN)

Vol. 2013 11 artikel nr 025-

Ämneskategorier

Fysik

Astronomi, astrofysik och kosmologi

DOI

10.1088/1475-7516/2013/11/025

Mer information

Skapat

2017-10-07