110 research outputs found
Comment on "Ruling out chaos in compact binary systems"
In a recent Letter, Schnittman and Rasio argue that they have ruled out chaos
in compact binary systems since they find no positive Lyapunov exponents. In
stark constrast, we find that the chaos discovered in the original paper under
discussion, J.Levin, PRL, 84 3515 (2000), is confirmed by the presence of
positive Lyapunov exponents.Comment: 1 page. Published Versio
Chaos and order in a finite universe
All inhabitants of this universe, from galaxies to people, are finite. Yet
the universe itself is often assumed to be infinite. If instead the universe is
topologically finite, then light and matter can take chaotic paths around the
compact geometry. Chaos may lead to ordered features in the distribution of
matter throughout space.Comment: 3 pages, contribution to the conference proceedings for ``The Chaotic
Universe'', ICRA, Rom
Big Black Hole, Little Neutron Star: Magnetic Dipole Fields in the Rindler Spacetime
As a black hole and neutron star approach during inspiral, the field lines of
a magnetized neutron star eventually thread the black hole event horizon and a
short-lived electromagnetic circuit is established. The black hole acts as a
battery that provides power to the circuit, thereby lighting up the pair just
before merger. Although originally suggested as a promising electromagnetic
counterpart to gravitational-wave detection, the luminous signals are promising
more generally as potentially detectable phenomena, such as short gamma-ray
bursts. To aid in the theoretical understanding, we present analytic solutions
for the electromagnetic fields of a magnetic dipole in the presence of an event
horizon. In the limit that the neutron star is very close to a Schwarzschild
horizon, the Rindler limit, we can solve Maxwell's equations exactly for a
magnetic dipole on an arbitrary worldline. We present these solutions here and
investigate a proxy for a small segment of the neutron star orbit around a big
black hole. We find that the voltage the black hole battery can provide is in
the range ~10^16 statvolts with a projected luminosity of 10^42 ergs/s for an
M=10M_sun black hole, a neutron star with a B-field of 10^12 G, and an orbital
velocity ~0.5c at a distance of 3M from the horizon. Larger black holes provide
less power for binary separations at a fixed number of gravitational radii. The
black hole/neutron star system therefore has a significant power supply to
light up various elements in the circuit possibly powering jets, beamed
radiation, or even a hot spot on the neutron star crust.Comment: Published in Physical Review D:
http://link.aps.org/doi/10.1103/PhysRevD.88.06405
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