David Wands, Karim A. Malik, David H. Lyth, and Andrew R. Liddle School of Computer Science and Mathematics, Mercantile House, University of Portsmouth, Portsmouth PO1 2EG, U. K. Department of… (More)

Model selection is the problem of distinguishing competing models, perhaps featuring different numbers of parameters. The statistics literature conta ins wo distinct sets of tools, those based on… (More)

We present a phase-plane analysis of cosmologies containing a barotropic fluid with equation of state pγ = (γ − 1)ργ, plus a scalar field φ with an exponential potential V ∝ exp(−λκφ) where κ = 8πG.… (More)

The abundance of new cosmological data becoming available means that a wider range of cosmological models are testable than ever before. However, an important distinction must be made between… (More)

We analyze the cosmic nongaussianity produced in inflation models with multiple uncoupled fields with monomial potentials, such as Nflation. Using the horizon-crossing approximation to compute the… (More)

We reconsider the issue of the number of e-foldings before the end of inflation at which observable perturbations were generated. We determine a plausible upper limit on that number for the standard… (More)

We consider the behaviour of a quintessence field during an inflationary epoch, in order to learn how inflation influences the likely initial conditions for quintessence. We use the stochastic… (More)

We re-examine the constraints on the density perturbation spectrum, including its spectral index n, from the production of primordial black holes. The standard cosmology, where the Universe is… (More)

We constrain slow-roll inflationary models using the recent Wilkinson Microwave Anisotropy Probe data combined with data from the VSA, CBI, ACBAR and 2dF experiments. We find the slow-roll parameters… (More)

Primordial black holes may form in the early Universe, for example from the collapse of large amplitude density perturbations predicted in some inflationary models. Light black holes undergo Hawking… (More)