Gravitational waves from a chaotic dynamical system

To investigate how chaos affects gravitational waves, we study the gravitational waves from a spinning test particle moving around a Kerr black hole, which is a typical chaotic system. To compare the result with those in a nonchaotic dynamical system, we also analyze a spinless test particle, whose orbit can be complicated in the Kerr back ground although the system is integrable. We estimate the emitted gravitational waves by the multipole expansion of a gravitational field. We find a striking difference in the energy spectra of the gravitational waves. The spectrum for a chaotic orbit of a spinning particle contains various frequencies, while some characteristic frequencies appear in the case of a spinless particle.