PT Journal
AU Simpson, F
   Jimenez, R
   Pena-Garay, C
   Verde, L
TI Dark energy from the motions of neutrinos
SO Physics of the Dark Universe
JI Phys. Dark Universe
PY 2018
BP 72
EP 77
VL 20
DI 10.1016/j.dark.2018.04.002
LA English
DE Neutrinos; Dark energy; Interactions in the dark sector
AB Ordinarily, a scalar field may only play the role of dark energy if it possesses a potential that is either extraordinarily flat or extremely fine-tuned. Here we demonstrate that these restrictions are lifted when the scalar field undergoes persistent energy exchange with another fluid. In this scenario, the field is prevented from reversing its direction of motion, and instead may come to rest while displaced from the local minimum of its potential. Therefore almost any scalar potential is capable of initiating a prolonged phase of cosmic acceleration. If the rate of energy transfer is modulated via a derivative coupling, the field undergoes a rapid process of freezing, after which the field's equation of state mimicks that of a cosmological constant. We present a physically motivated realisation in the form of a neutrino-majoron coupling, which avoids the dynamical instabilities associated with mass-varying neutrino models. Finally we discuss possible means by which this model could be experimentally verified.
ER