We study the ultraviolet complete non-relativistic theory recently proposed by HoÅ™ava. After introducing a Lifshitz scalar for a general background, we analyze the cosmology of the model inâ€¦ (More)

This is an introduction to loop quantum cosmology (LQC) reviewing miniand midisuperspace models as well as homogeneous and inhomogeneous effective dynamics.

We propose a field theory which lives in fractal spacetime and is argued to be Lorentz invariant, power-counting renormalizable, ultraviolet finite, and causal. The system flows from an ultravioletâ€¦ (More)

An analytic approach to phenomenological models inspired by cubic string field theory is introduced and applied to some examples. We study a class of actions for a minimally coupled, homogeneousâ€¦ (More)

The full set of cosmological observables coming from linear scalar and tensor perturbations of loop quantum cosmology is computed in the presence of inverse-volume corrections. Backgroundâ€¦ (More)

We show that the effective dynamics of the recently proposed isotropic condensate state of group field theory with Laplacian kinetic operator can be equivalent to that of homogeneous and isotropicâ€¦ (More)

The classical dynamics of the tachyon scalar field of cubic string field theory is considered on a cosmological background. Starting from a nonlocal action with arbitrary tachyon potential, whichâ€¦ (More)

Recently, evidence has been collected that a class of gravitational theories with certain non-local operators is renormalizable. We consider one such model which, at the linear perturbative level,â€¦ (More)

We construct rolling tachyon solutions of cubic and boundary string field theory (CSFT and BSFT, respectively), in the bosonic and supersymmetric (susy) case. A solution of susy CSFT is presented,â€¦ (More)

In the context of loop quantum cosmology, we consider an inflationary era driven by a canonical scalar field and occurring in the semiclassical regime, where spacetime is a continuum but quantumâ€¦ (More)