Publication date: Dec 2010
Abstract:
Current-carrying string loop dynamics in Schwarzschild-de Sitter
spacetimes characterized by the cosmological parameter
λ=(1)/(3)ΛM2 is investigated. With attention
concentrated to the axisymmetric motion of string loops it is shown that
the resulting motion is governed by the presence of an outer tension
barrier and an inner angular momentum barrier that are influenced by the
black hole gravitational field given by the mass M and the cosmic
repulsion given by the cosmological constant Λ. The gravitational
attraction could cause capturing of the string having low energy by the
black hole or trapping in its vicinity; with high enough energy, the
string can escape (scatter) to infinity. The role of the cosmic
repulsion becomes important in vicinity of the so-called static radius
where the gravitational attraction is balanced by the cosmic
repulsion—it is demonstrated both in terms of the effective
potential of the string motion and the basin boundary method reflecting
its chaotic character, that a potential barrier exists along the static
radius behind which no trapped oscillations may exist. The trapped
states of the string loops, governed by the interplay of the gravitating
mass M and the cosmic repulsion, are allowed only in Schwarzschild-de
Sitter spacetimes with the cosmological parameter
λ<λtrap˜0.00497. The trapped
oscillations can extend close to the radius of photon circular orbit,
down to rmt˜3.3M.
Authors:
Kološ, M.; Stuchlík, Z.;