Particlelike solutions in modified gravity: the Higgs monopole

Abstract

Higgs inflation has received a remarkable attention in the last few years due to its simplicity and predictive power. The key point of this model is the nonminimal coupling to gravity in unitary gauge. As such, this theory is in fact a scalar-tensor modification of gravity that needs to be studied also below the energy scales of inflation. Motivated by this goal, we study in great analytical and numerical detail the static and spherically symmetric solutions of the equations of motion in the presence of standard baryonic matter, called "Higgs monopoles" and presented in 1305.2640. These particlelike solutions may arise naturally in tensor-scalar gravity with mexican hat potential and are the only globally regular asymptotically flat solutions with finite classical energy. In the case when the parameters of the potential are taken to be the ones of the standard model, we find that the deviations from general relativity are extremely small, especially for bodies of astrophysical size and density. This allows to derive a simplified description of the monopole, for which the metric inside the spherical matter distribution can be approximated by the standard metric of general relativity. We study how the properties of these monopoles depend on the strength of the nonminimal coupling to gravity and on the baryonic mass and compactness. An important and original result is the existence of a mechanism of resonant amplification of the Higgs field inside the monopole that comes into play for large nonminimal coupling. We show that this mechanism might degenerate into divergences of the Higgs field that reveal the existence of forbidden combinations of radius and baryonic energy density.

19 pages, 17 figures, version accepted by PRD

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Cited by in corpus (8)

• Post-Newtonian parameter $\gamma$ for multiscalar-tensor gravity with a general potential
• Higgs Dark Energy
• Mimicking dark matter in Horndeski gravity
• Neutron Star Structure in the Presence of Nonminimally Coupled Scalar Fields
• Uniqueness of the Inflationary Higgs Scalar for Neutron Stars and Failure of non-inflationary Approximations
• Compact Objects in Entangled Relativity
• Self-Gravitating Spherical Solutions of the non-minimally coupled non-Abelian Higgs Model
• A Neutron Star with a Strange Quark Star-like Mass-Radius Relation