We explore a version of the cosmological dilaton-fixing and decoupling mechanism in which the dilaton-dependence of the low-energy effective action is extremized for infinitely large values of the… (More)

We have recently proposed a new class of gravitational scalar-tensor theories free from Ostrogradski instabilities, in Ref. [1]. As they generalize Horndeski theories, or “generalized” galileons, we… (More)

In a recently proposed scenario, where the dilaton decouples while cosmologically attracted towards infinite bare string coupling, its residual interactions can be related to the amplitude of density… (More)

We show that curvature perturbations acquire a scale invariant spectrum for any constant equation of state, provided the fluid has a suitably time-dependent sound speed. In order for modes to exit… (More)

Space-time measurements and gravitational experiments are made by using objects , matter fields or particles and their mutual relationships. As a consequence, any operationally meaningful assertion… (More)

We consider a late-time cosmological model based on a recent proposal that the infinite-bare-coupling limit of superstring/M-theory exists and has good phenomenological properties, including a… (More)

We adapt the Goldstone theorem to study spontaneous symmetry breaking in relativistic theories at finite charge density. It is customary to treat systems at finite density via nonrelativistic… (More)

Standard entropy calculations in quantum field theory, when applied to a subsystem of definite volume, exhibit area-dependent UV divergences that make a thermodynamic interpretation troublesome. Such… (More)

We explore a dark energy model with a ghost scalar field in the context of the runaway dilaton scenario in low-energy effective string theory. We address the problem of vacuum stability by… (More)

The equivalence principle suggests to consider gravity as an infra-red phenomenon, whose effects are visible only outside Einstein’s free-falling elevator. By curving spacetime, General Relativity… (More)