4 research outputs found
Q-stars in extra dimensions
We study q-stars with global and local U(1) symmetry in extra dimensions in
asymptotically anti de Sitter or flat spacetime. The behavior of the mass,
radius and particle number of the star is quite different in 3 dimensions, but
in 5, 6, 8 and 11 dimensions is similar to the behavior in 4.Comment: 18 pages, to appear in Phys. Rev.
EYM equations in the presence of q-stars
We study Einstein-Yang-Mills equations in the presence of gravitating
non-topological soliton field configurations, of q-ball type. We produce
numerical solutions, stable with respect to gravitational collapse and to
fission into free particles, and we study the effect of the field strength and
the eigen-frequency to the soliton parameters. We also investigate the
formation of such soliton stars when the spacetime is asymptotically anti de
Sitter.Comment: 11 pages, to appear in Phys. Rev.
Boson-fermion stars: exploring different configurations
We use the flexibility of the concept of a fermion-boson star to explore
different configurations, ranging from objects of atomic size and masses of the
order g, up to objects of galactic masses and gigantic halos around a
smaller core, with possible interesting applications to astrophysics and
cosmology, particularly in the context of dark matter.Comment: 8 pages. Minor changes, new reference added and a few typos correcte
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An upper bound on Q-star masses
Q-stars (the gravitational generalization of Q-balls, strongly bound bulk matter that an appear in field theories of strongly interacting hadrons) are the only known impact objects consistent with the known bulk structure of nuclei and chiral symmetry that evade the Rhoades-Ruffini upper bound of 3.2M{sub {circle_dot}}. Generic bounds are quite weak: M{sub Q-star} < 400M{sub {circle_dot}}. If, however, we assume that the 1.558 ms pulsar is a Q-star, equilibrium. A stability criteria of rotating fluids place a much stronger upper bound of M{sub c} {le} 5.3M{sub {circle_dot}} on such models under certain special assumptions. This has important implications for heavy compact objects such as Cygnus X-1