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The quadratic approximation for quintessence with arbitrary initial conditions
(Vanderbilt University. Department of Physics and Astronomy, 2014-04)
We examine models of quintessence in which a minimally-coupled scalar field phi evolves near a local extremum of its potential V ( phi) at phi_*. Assuming that (1/V )(dV/dphi) is small and w ~ -1, we Taylor expand the ...
Dark radiation from particle decays during big bang nucleosynthesis
(Vanderbilt University. Dept. of Physics and Astronomy, 2012-04)
Cosmic microwave background (CMB) observations suggest the possibility of an extra dark radiation component, while the current evidence from big bang nucleosynthesis (BBN) is more ambiguous. Dark radiation from a decaying ...