Gravitational magnetic monopoles and MajumdarPapapetrou stars
Abstract
A large amount of work has been dedicated to studying general relativity coupled to nonAbelian YangMills type theories. It has been shown that the magnetic monopole, a solution of the YangMillsHiggs equations can be coupled to gravitation. For a low Higgs mass there are regular solutions, and for a sufficiently massive monopole the system develops an extremal magnetic ReissnerNordstrom quasihorizon. These solutions, called quasiblack holes, although nonsingular, are arbitrarily close to having a horizon. However, at the critical value the quasiblack hole turns into a degenerate spacetime. On the other hand, for a high Higgs mass, a sufficiently massive monopole develops also a quasiblack hole, but it turns into an extremal true horizon, with matter fields outside. One can also put a small Schwarzschild black hole inside the magnetic monopole, an example of a nonAbelian black hole. Surprisingly, MajumdarPapapetrou systems, Abelian systems constructed from extremal dust, also show a resembling behavior. Previously, we have reported that one can find MajumdarPapapetrou solutions which can be arbitrarily close of being a black hole, displaying quasiblack hole behavior. With the aim of better understanding the similarities between gravitational monopoles and MajumdarPapapetrou systems, we study a system composed of two extremal electrically charged spherical shells (or stars, generically) in the EinsteinMaxwellMajumdarPapapetrou theory. We review the gravitational properties of the monopoles, and compare with the properties of the double extremal electric shell system. These quasiblack holes can help in the understanding of true black holes, and can give insight into the nature of the entropy of black holes in the form of entanglement.
 Publication:

Journal of Mathematical Physics
 Pub Date:
 April 2006
 DOI:
 10.1063/1.2184766
 arXiv:
 arXiv:grqc/0603101
 Bibcode:
 2006JMP....47d2504L
 Keywords:

 97.60.Lf;
 14.80.Hv;
 11.15.q;
 97.10.Cv;
 95.30.Cq;
 95.30.Sf;
 Black holes;
 Magnetic monopoles;
 Gauge field theories;
 Stellar structure interiors evolution nucleosynthesis ages;
 Elementary particle processes;
 Relativity and gravitation;
 General Relativity and Quantum Cosmology;
 Astrophysics;
 High Energy Physics  Theory
 EPrint:
 38 pages,9 Figures, minor changes