Black Hole Solutions and Pressure Terms in Induced Gravity with Higgs Potential

We study the quintessential properties of the Black Hole solutions in a scalar--tensor theory of gravity with Higgs potential in view of the static and spherically symmetric line element. In view of our earlier results, Reissner--Nordstr\"om-like and Schwarzschild Black Hole solutions are derived with the introduction of a series-expansion method to solve the field equations without and with Higgs field mass. The physical consequences of the Black Hole solutions and the solutions obtained in the weak field limit are discussed in detail by the virtue of the equation-of-state parameter, the scalar-field excitations and the geodesic motion. The appearance of naked singularities is also discussed together with the dependence of Black Hole horizons on the field excitations, which are themselves dependent on pressure terms which effectively screen the mass terms. A possible connection to flat rotation curves following the interaction with the scalar field is also presented in the weak field limit of gravity, together with a discussion of dynamical effects of scalar fields and pressure terms on mass.Comment: 28 pages, 4 figures, contents and figures modified, major revision, results are unchanged, published in Classical and Quantum Gravit

Higgs Scalar-Tensor Theory for Gravity and the Flat Rotation Curves of Spiral Galaxies

The scalar-tensor theory of gravity with the Higgs field as scalar field is presented. For central symmetry it reproduces the empirically measured flat rotation curves of galaxies. We approximate the galaxy by a polytropic gas sphere with the polytropic index $\gamma=2$ and a massive core.Comment: 17 pages, 12 figure

Non-minimal monopoles of the Dirac type as realization of the censorship conjecture

We discuss a class of exact solutions of a three-parameter non-minimally extended Einstein-Maxwell model, which are attributed to non-minimal magnetic monopoles of the Dirac type. We focus on the investigation of the gravitational field of Dirac monopoles for those models, for which the singularity at the central point is hidden inside of an event horizon independently on the mass and charge of the object. We obtained the relationships between the non-minimal coupling constants, for which this requirement is satisfied. As explicit examples, we consider in detail two one-parameter models: first, non-minimally extended Reissner-Nordstr\"om model (for the magnetically charged monopole), second, the Drummond-Hathrell model.Comment: 9 pages; one reference added, accepted to Phys. Rev.

Scalar-field Pressure in Induced Gravity with Higgs Potential and Dark Matter

A model of induced gravity with a Higgs potential is investigated in detail in view of the pressure components related to the scalar-field excitations. The physical consequences emerging as an artifact due to the presence of these pressure terms are analysed in terms of the constraints parting from energy density, solar-relativistic effects and galactic dynamics along with the dark matter halos.Comment: 26 pages, 3 figures, Minor revision, Published in JHE