Late-Time Dynamics of Scalar Fields on Rotating Black Hole Backgrounds

TL;DR

This paper numerically investigates the late-time behavior of scalar fields on rotating black holes, revealing that the decay rates differ from non-rotating cases and challenge previous analytic predictions.

Contribution

It provides new numerical insights into scalar field decay on Kerr backgrounds, especially regarding multipole mixing and late-time fall-off behaviors.

Findings

Late-time decay dominated by lowest multipole

Decay rates differ from Schwarzschild case

Results challenge recent analytic predictions

Abstract

Motivated by results of recent analytic studies, we present a numerical investigation of the late-time dynamics of scalar test fields on Kerr backgrounds. We pay particular attention to the issue of mixing of different multipoles and their fall-off behavior at late times. Confining ourselves to the special case of axisymmetric modes with equatorial symmetry, we show that, in agreement with the results of previous work, the late-time behavior is dominated by the lowest allowed l-multipole. However the numerical results imply that, in general, the late-time fall-off of the dominating multipole is different from that in the Schwarzschild case, and seems to be incompatible with a result of a recently published analytic study.