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;