6,739 research outputs found
Black hole binary inspiral and trajectory dominance
Gravitational waves emitted during the inspiral, plunge and merger of a black
hole binary carry linear momentum. This results in an astrophysically important
recoil to the final merged black hole, a ``kick'' that can eject it from the
nucleus of a galaxy. In a previous paper we showed that the puzzling partial
cancellation of an early kick by a late antikick, and the dependence of the
cancellation on black hole spin, can be understood from the phenomenology of
the linear momentum waveforms. Here we connect that phenomenology to its
underlying cause, the spin-dependence of the inspiral trajectories. This
insight suggests that the details of plunge can be understood more broadly with
a focus on inspiral trajectories.Comment: 15 pages, 12 figure
Systematics of black hole binary inspiral kicks and the slowness approximation
During the inspiral and merger of black holes, the interaction of
gravitational wave multipoles carries linear momentum away, thereby providing
an astrophysically important recoil, or "kick" to the system and to the final
black hole remnant. It has been found that linear momentum during the last
stage (quasinormal ringing) of the collapse tends to provide an "antikick" that
in some cases cancels almost all the kick from the earlier (quasicircular
inspiral) emission. We show here that this cancellation is not due to
peculiarities of gravitational waves, black holes, or interacting multipoles,
but simply to the fact that the rotating flux of momentum changes its intensity
slowly. We show furthermore that an understanding of the systematics of the
emission allows good estimates of the net kick for numerical simulations
started at fairly late times, and is useful for understanding qualitatively
what kinds of systems provide large and small net kicks.Comment: 15 pages, 6 figures, 2 table
Landau Ginzburg Theory and Nuclear Matter at Finite Temperature
Based on recent studies of the temperature dependence of the energy and
specific heat of liquid nuclear matter, a phase transition is suggested at a
temperature MeV. We apply Landau Ginzburg theory to this transition
and determine the behaviour of the energy and specific heat close to the
critical temperature in the condensed phase.Comment: 10 pages, Revte
Massive scalar field instability in Kerr spacetime
We study the Klein-Gordon equation for a massive scalar field in Kerr
spacetime in the time-domain. We demonstrate that under conditions of
super-radiance, the scalar field becomes unstable and its amplitude grows
without bound. We also estimate the growth rate of this instability.Comment: 10 pages, 5 figure
Absence of pre-classical solutions in Bianchi I loop quantum cosmology
Loop quantum cosmology, the symmetry reduction of quantum geometry for the
study of various cosmological situations, leads to a difference equation for
its quantum evolution equation. To ensure that solutions of this equation act
in the expected classical manner far from singularities, additional
restrictions are imposed on the solution. In this paper, we consider the
Bianchi I model, both the vacuum case and the addition of a cosmological
constant, and show using generating function techniques that only the zero
solution satisfies these constraints. This implies either that there are
technical difficulties with the current method of quantizing the evolution
equation, or else loop quantum gravity imposes strong restrictions on the
physically allowed solutions.Comment: 4 pages, no figures, version to appear in PR
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