Gravitational self-regularization of quantum fields at Planck scales

Loop diagrams with near-Planck energies create a strong external gravitational field, which slows down local processes for distant observers up to their freezing. Since Planck length is the gravitational radius of the system of quanta, the events of this and smaller scale cannot occur in finite world time t and do not contribute to the S-matrix. Consequently, gravitational time dilation, leading to a strong redshift of local frequencies, provides gravitational self-regularization of the loop diagrams. The loop corrections without gravity effects, cut off at Planck energy, give upper bounds for the corrections with gravity effects and this fact leads to simple rules of gravitational regularization. The corrections with quanta of gauge fields and gravitons are small, and the perturbation theory series converge. At pre-Planck energies, one-loop graviton contributions are sufficient, since the multi-loop ones are damped by high degrees of the relation “energy/Planck energy”. Scalar field with power-law growing corrections should be effective field. Non-linearity of fields enhances gravity and get faster freezing, which suppresses the high energy terms. Nonrenormalizable models are finite, but become consistent only when their loop corrections remain small on Planck scale and this occurs in quantum gravity. Gravitationally regularized Extended Standard Model (ESM), including gravitons and Standard Model with effective scalars, is renormalizable and finite, which simplifies its further generalization.

Gravity resonance spectroscopy and dark energy symmetron fields

Spectroscopic methods allow to measure energy differences with unrivaled precision. In the case of gravity resonance spectroscopy, energy differences of different gravitational states are measured without recourse to the electromagnetic interaction. This provides a very pure and background-free look at gravitation and topics related to the central problem of dark energy and dark matter at short distances. In this article, we analyse the effect of dark energy scalar symmetron fields, a leading candidate for a screened dark energy field, and place limits in a large volume of parameter space.

Transmission of low-energy scalar waves through a traversable wormhole

We study the scattering of low-energy massless and massive minimally coupled scalar fields by an asymptotically flat traversable wormhole. We provide a comprehensive treatment of this problem offering analytic expressions for the transmission and reflection amplitudes of the corresponding effective potential and the absorption cross section of the wormhole. Our results, which are based on a recently developed dynamical formulation of time-independent scattering theory, apply to a large class of wormhole spacetimes including a wormhole with a sharp transition, the Ellis wormhole, and a family of its generalizations.

Dynamical dark energy: Scalar fields and running vacuum

Recent analyses in the literature suggest that the concordance [Formula: see text]CDM model with rigid cosmological term, [Formula: see text] may not be the best description of the cosmic acceleration. The class of “running vacuum models”, in which [Formula: see text] evolves with the Hubble rate, has been shown to fit the string of SNIa + BAO + H(z) + LSS + CMB data significantly better than the [Formula: see text]CDM. Here, we provide further evidence on the time-evolving nature of the dark energy (DE) by fitting the same cosmological data in terms of scalar fields. As a representative model, we use the original Peebles and Ratra potential, [Formula: see text]. We find clear signs of dynamical DE at [Formula: see text] c.l., thus reconfirming through a nontrivial scalar field approach the strong hints formerly found with other models and parametrizations.