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Cosmology with matter diffusion

Simone Calogero (Institutionen för matematiska vetenskaper, matematik) ; H. Velten
Journal of Cosmology and Astroparticle Physics (1475-7516). Vol. 2013 (2013), 11, p. artikel nr 025.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: power spectrum, dark matter theory, cosmological parameters from LSS, dark energy theory, BARYON ACOUSTIC-OSCILLATIONS, DIGITAL SKY SURVEY, DARK-ENERGY, HUBBLE, CONSTANT, CONSTRAINTS, MODELS, PERTURBATIONS, CONSEQUENCES, EQUATION, DISTANCE



Denna post skapades 2014-01-17. Senast ändrad 2015-02-11.
CPL Pubid: 192786

 

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Institutioner (Chalmers)

Institutionen för matematiska vetenskaper, matematik (2005-2016)

Ämnesområden

Fysik
Astronomi, astrofysik och kosmologi

Chalmers infrastruktur