856 research outputs found
Effective field theory calculation of conservative binary dynamics at third post-Newtonian order
We reproduce the two-body gravitational conservative dynamics at third
post-Newtonian order for spin-less sources by using the effective field theory
methods for the gravitationally bound two-body system, proposed by Goldberger
and Rothstein. This result has been obtained by automatizing the computation of
Feynman amplitudes within a Mathematica algorithm, paving the way for
higher-order computations not yet performed by traditional methods.Comment: 24 pages, 6 figures. Typos corrected and references added in v2.
Typos corrected in v
Aligned Spins: Orbital Elements, Decaying Orbits, and Last Stable Circular Orbit to high post-Newtonian Orders
In this article the quasi-Keplerian parameterisation for the case that spins
and orbital angular momentum in a compact binary system are aligned or
anti-aligned with the orbital angular momentum vector is extended to 3PN
point-mass, next-to-next-to-leading order spin-orbit, next-to-next-to-leading
order spin(1)-spin(2), and next-to-leading order spin-squared dynamics in the
conservative regime. In a further step, we use the expressions for the
radiative multipole moments with spin to leading order linear and quadratic in
both spins to compute radiation losses of the orbital binding energy and
angular momentum. Orbital averaged expressions for the decay of energy and
eccentricity are provided. An expression for the last stable circular orbit is
given in terms of the angular velocity type variable .Comment: 30 pages, 2 figures, v2: update to match published versio
Higgs-graviscalar mixing in type I string theory
We investigate the possibility of mixing between open and closed string
excitations in D-brane models with the fundamental string scale at the TeV. The
open string modes describe the Standard Model Higgs, while closed strings
describe graviscalars living in the bulk. This provides a string setup for
computing the Higgs-graviscalar mixing, that leads to a phenomenologically
interesting invisible width of the Higgs in low scale quantum gravity models,
as suggested previously by Giudice, Rattazzi and Wells.Comment: 20 pages, typos correcte
Events trigger generator for resonant spherical detectors of gravitational waves
We have set up and tested a pipeline for processing the data from a spherical
gravitational wave detector with six transducers. The algorithm exploits the
multichannel capability of the system and provides a list of candidate events
with their arrival direction. The analysis starts with the conversion of the
six detector outputs into the scalar and the five quadrupolar modes of the
sphere, which are proportional to the corresponding gravitational wave
spherical components. Event triggers are then generated by an adaptation of the
WaveBurst algorithm. Event validation and direction reconstruction are made by
cross-checking two methods of different inspiration: geometrical (lowest
eigenvalue) and probabilistic (maximum likelihood). The combination of the two
methods is able to keep substantially unaltered the efficiency and can reduce
drastically the detections of fake events (to less than ten per cent). We show
a quantitative test of these ideas by simulating the operation of the resonant
spherical detector miniGRAIL, whose planned sensitivity in its frequency band
(few hundred Hertz's around 3 kHz) is comparable with the present LIGO one.Comment: 14 pages, 8 figures. Version accepted for publication on CQG.
Proceedings of the 12th Gravitational Wave Data Analysis Worksho
Complete phenomenological gravitational waveforms from spinning coalescing binaries
The quest for gravitational waves from coalescing binaries is customarily
performed by the LIGO-Virgo collaboration via matched filtering, which requires
a detailed knowledge of the signal. Complete analytical coalescence waveforms
are currently available only for the non-precessing binary systems. In this
paper we introduce complete phenomenological waveforms for the dominant
quadrupolar mode of generically spinning systems. These waveforms are
constructed by bridging the gap between the analytically known inspiral phase,
described by spin Taylor (T4) approximants in the restricted waveform
approximation, and the ring-down phase through a phenomenological intermediate
phase, calibrated by comparison with specific, numerically generated waveforms,
describing equal mass systems with dimension-less spin magnitudes equal to 0.6.
The overlap integral between numerical and phenomenological waveforms ranges
between 0.95 and 0.99.Comment: Proceeding for the GWDAW-14 conference. Added reference in v
- …