Speaker
Description
The combination of cosmic microwave background (CMB) measurements with distance measurements from baryon
acoustic oscillations (BAO) and type Ia supernovae (SNIa) suggests that dark energy is dynamical, with an equation of
state crossing the phantom divide at low redshifts. This feature can not be described within canonically normalized,
minimally coupled, self-interacting scalar field models. We investigate the possibility of achieving phantom crossing by
introducing an interaction in the dark sector such that the dark matter particle mass is dependent on the dark energy field
ϕ as $m \propto ϕ^{α}$
. We consider a self-interacting potential of the inverse power-law form $V \propto ϕ^{−β}$. We implement this model
both at the background and perturbative levels in a Boltzmann solver and use a bayesian framework to constrain its
parameters using using CMB, BAO and SNIa data. We find best-fits that have similar goodness-of-fits as the commonly
used phenomenological w0 − wa parameterization, providing a more fundamental understanding of the dark sector
| Academic position of the presenting author | Professor |
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