Publication date: Jun 2006
Abstract:
Equilibrium conditions and spin dynamics of spinning test particles are
discussed in the stationary and axially symmetric Kerr de Sitter
black-hole or naked-singularity spacetimes. The general equilibrium
conditions are established, but due to their great complexity, the
detailed discussion of the equilibrium conditions and spin dynamics is
presented only in the simple and most relevant cases of equilibrium
positions in the equatorial plane and on the symmetry axis of the
spacetimes. It is shown that due to the combined effect of the rotation
of the source and the cosmic repulsion the equilibrium is spin dependent
in contrast to the spherically symmetric spacetimes. In the equatorial
plane, it is possible at the so-called static radius, where the
gravitational attraction is balanced by the cosmic repulsion, for the
spinless particles as well as for spinning particles with arbitrarily
large phiv-oriented spin or at any radius outside the ergosphere with a
specifically given spin orthogonal to the equatorial plane. On the
symmetry axis, the equilibrium is possible at any radius in the
stationary region and is given by an appropriately tuned spin directed
along the axis. At the static radii on the axis the spin of particles in
equilibrium must vanish.
Authors:
Stuchlík, Zdenek; Kovár, Jirí;