4,953 research outputs found
Geometric transport along circular orbits in stationary axisymmetric spacetimes
Parallel transport along circular orbits in orthogonally transitive
stationary axisymmetric spacetimes is described explicitly relative to Lie
transport in terms of the electric and magnetic parts of the induced
connection. The influence of both the gravitoelectromagnetic fields associated
with the zero angular momentum observers and of the Frenet-Serret parameters of
these orbits as a function of their angular velocity is seen on the behavior of
parallel transport through its representation as a parameter-dependent Lorentz
transformation between these two inner-product preserving transports which is
generated by the induced connection. This extends the analysis of parallel
transport in the equatorial plane of the Kerr spacetime to the entire spacetime
outside the black hole horizon, and helps give an intuitive picture of how
competing "central attraction forces" and centripetal accelerations contribute
with gravitomagnetic effects to explain the behavior of the 4-acceleration of
circular orbits in that spacetime.Comment: 33 pages ijmpd latex article with 24 eps figure
Inertial effects of an accelerating black hole
We consider the static vacuum C metric that represents the gravitational
field of a black hole of mass undergoing uniform translational acceleration
such that . The influence of the inertial acceleration on
the exterior perturbations of this background are investigated. In particular,
we find no evidence for a direct spin-acceleration coupling.Comment: Proceedings of the XVI Conference of the Italian Society for General
Relativity and Gravitation (SIGRAV), Vietri (SA), September 13-16, 2004.
Prepared using revtex4 macro
Energy and angular momentum of general 4-dimensional stationary axi-symmetric spacetime in teleparallel geometry
We derive an exact general axi-symmetric solution of the coupled
gravitational and electromagnetic fields in the tetrad theory of gravitation.
The solution is characterized by four parameters (mass), (charge),
(rotation) and (NUT). We then, calculate the total exterior energy using
the energy-momentum complex given by M{\o}ller in the framework of
Weitzenbck geometry. We show that the energy contained in a sphere is
shared by its interior as well as exterior. We also calculate the components of
the spatial momentum to evaluate the angular momentum distribution. We show
that the only non-vanishing components of the angular momentum is in the Z
direction.Comment: Latex. Will appear in IJMP
Circular holonomy in the Taub-NUT spacetime
Parallel transport around closed circular orbits in the equatorial plane of
the Taub-NUT spacetime is analyzed to reveal the effect of the gravitomagnetic
monopole parameter on circular holonomy transformations. Investigating the
boost/rotation decomposition of the connection 1-form matrix evaluated along
these orbits, one finds a situation that reflects the behavior of the general
orthogonally transitive stationary axisymmetric case and indeed along Killing
trajectories in general.Comment: 9 pages, LaTeX iopart class, no figure
Design and Implementation of Distributed Resource Management for Time Sensitive Applications
In this paper, we address distributed convergence to fair allocations of CPU
resources for time-sensitive applications. We propose a novel resource
management framework where a centralized objective for fair allocations is
decomposed into a pair of performance-driven recursive processes for updating:
(a) the allocation of computing bandwidth to the applications (resource
adaptation), executed by the resource manager, and (b) the service level of
each application (service-level adaptation), executed by each application
independently. We provide conditions under which the distributed recursive
scheme exhibits convergence to solutions of the centralized objective (i.e.,
fair allocations). Contrary to prior work on centralized optimization schemes,
the proposed framework exhibits adaptivity and robustness to changes both in
the number and nature of applications, while it assumes minimum information
available to both applications and the resource manager. We finally validate
our framework with simulations using the TrueTime toolbox in MATLAB/Simulink
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