Self-force on a scalar charge in Kerr spacetime: Circular equatorial orbits

Journal Article · Thu Apr 15 00:00:00 EDT 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.81.084039· OSTI ID:21409613

Warburton, Niels; Barack, Leor ^[1]

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1. School of Mathematics, University of Southampton, Southampton SO17 1BJ (United Kingdom)

We present a calculation of the scalar-field self-force (SSF) acting on a scalar-charge particle in a strong-field orbit around a Kerr black hole. Our calculation specializes to circular and equatorial geodesic orbits. The analysis is an implementation of the standard mode-sum regularization scheme: We first calculate the multipole modes of the scalar-field perturbation using numerical integration in the frequency domain, and then apply a certain regularization procedure to each of the modes. The dissipative piece of the SSF is found to be consistent with the flux of energy and angular-momentum carried by the scalar waves through the event horizon and out to infinity. The conservative (radial) component of the SSF is calculated here for the first time. When the motion is retrograde this component is found to be repulsive (outward pointing, as in the Schwarzschild case) for any spin parameter a and (Boyer-Lindquist) orbital radius r{sub 0}. However, for prograde orbits we find that the radial SSF becomes attractive (inward pointing) for r{sub 0}>r{sub c}(a), where r{sub c} is a critical a-dependent radius at which the radial SSF vanishes. The dominant conservative effect of the SSF in Schwarzschild spacetime is known to be of third post-Newtonian (3PN) order (with a logarithmic running). Our numerical results suggest that the leading-order PN correction due to the black hole's spin arises from spin-orbit coupling at 3PN order, which dominates the overall SSF effect at large r{sub 0}. In PN language, the change of sign of the radial SSF is attributed to an interplay between the spin-orbit term ({proportional_to}-ar{sub 0}{sup -4.5}) and the Schwarzschild term ({proportional_to}r{sub 0}{sup -5}logr{sub 0}).

• OSTI ID: 21409613
• Journal Information: Physical Review. D, Particles Fields, Vol. 81, Issue 8; Other Information: DOI: 10.1103/PhysRevD.81.084039; (c) 2010 The American Physical Society; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BLACK HOLES
COMPUTERIZED SIMULATION
CORRECTIONS
DISTURBANCES
KERR FIELD
L-S COUPLING
ORBITS
PARTICLES
PERTURBATION THEORY
SCALAR FIELDS
SCHWARZSCHILD METRIC
SPACE-TIME
SPIN
ANGULAR MOMENTUM
COUPLING
GRAVITATIONAL FIELDS
INTERMEDIATE COUPLING
METRICS
PARTICLE PROPERTIES
SIMULATION