Abstract
We investigate the cosmological implications of a two-component dark matter superfluid
as proposed by Ferreira et al. (2019). Through contact interactions between the axionlike particles in these components, a late-time potential dominates the energy content of
the universe and leads to vacuum energy-like accelerated expansion. We test this model
in three ways: by evolving the Hubble parameter to very late-times, by comparing the
luminosity distance to type 1a supernova observations, and by comparing theoretical
values of the CMB shift parameter and dark matter density parameter to those from
WMAP.
In terms of the Hubble parameter, we find that it is similar to ΛCDM from the surface
of last scattering until the present when the interaction potential causes a significant
difference. We find that the luminosity distances predicted by the model agree with
supernova distance moduli for z < 1.3 for a certain range of energy gaps between the
two superfluid states. Finally, given accepted CMB shift parameter values, we derive
constraints on the dark matter density parameter Ωm = .255 ± .035, which agrees with
that from SDSS-II/SNLS results of Ωm = .295 ± .035.
Veileder: Professor Øystein Elgarøy, Institutt for teoretisk astrofysikk, UiO
Intern sensor: Professor David Fonseca Mota, Institutt for teoretisk astrofysikk, UiO
Ekstern sensor: Professor Anders Tranberg, UiS