1,367 research outputs found
Binary black hole detection rates in inspiral gravitational wave searches
The signal-to-noise ratios (SNRs) for quasi-circular binary black hole
inspirals computed from restricted post-Newtonian waveforms are compared with
those attained by more complete post-Newtonian signals, which are
superpositions of amplitude-corrected harmonics of the orbital phase. It is
shown that if one were to use the best available amplitude-corrected waveforms
for detection templates, one should expect SNRs in actual searches to be
significantly lower than those suggested by simulations based purely on
restricted waveforms.Comment: 9 pages, 1 figur
The Three Faces of the Second Law: II. Fokker-Planck Formulation
The total entropy production is the sum of two contributions, the so-called
adiabatic and nonadiabatic entropy production, each of which is non-negative.
We derive their explicit expressions for continuous Markov processes, discuss
their properties and illustrate their behavior on two exactly solvable models.Comment: 7 pages, 1 figur
Testing the multipole structure and conservative dynamics of compact binaries using gravitational wave observations: The spinning case
In an earlier work [S. Kastha et al., PRD {\bf 98}, 124033 (2018)], we
developed the {\it parametrized multipolar gravitational wave phasing formula}
to test general relativity, for the non-spinning compact binaries in
quasi-circular orbit. In this paper, we extend the method and include the
important effect of spins in the inspiral dynamics. Furthermore, we consider
parametric scaling of PN coefficients of the conserved energy for the compact
binary, resulting in the parametrized phasing formula for non-precessing
spinning compact binaries in quasi-circular orbit. We also compute the
projected accuracies with which the second and third generation ground-based
gravitational wave detector networks as well as the planned space-based
detector LISA will be able to measure the multipole deformation parameters and
the binding energy parameters. Based on different source configurations, we
find that a network of third-generation detectors would have comparable ability
to that of LISA in constraining the conservative and dissipative dynamics of
the compact binary systems. This parametrized multipolar waveform would be
extremely useful not only in deriving the first upper limits on any deviations
of the multipole and the binding energy coefficients from general relativity
using the gravitational wave detections, but also for science case studies of
next generation gravitational wave detectors.Comment: 16 pages, 8 figures, Mathematica readable supplemental material file
for all the inputs to calculate the parametrized waveform is with the sourc
Critical Behaviour of Non-Equilibrium Phase Transitions to Magnetically Ordered States
We describe non-equilibrium phase transitions in arrays of dynamical systems
with cubic nonlinearity driven by multiplicative Gaussian white noise.
Depending on the sign of the spatial coupling we observe transitions to
ferromagnetic or antiferromagnetic ordered states. We discuss the phase
diagram, the order of the transitions, and the critical behaviour. For global
coupling we show analytically that the critical exponent of the magnetization
exhibits a transition from the value 1/2 to a non-universal behaviour depending
on the ratio of noise strength to the magnitude of the spatial coupling.Comment: 4 pages, 5 figure
Higher signal harmonics, LISA's angular resolution, and dark energy
It is generally believed that the angular resolution of the Laser
Interferometer Space Antenna (LISA) for binary supermassive black holes (SMBH)
will not be good enough to identify the host galaxy or galaxy cluster. This
conclusion, based on using only the dominant harmonic of the binary SMBH
signal, changes substantially when higher signal harmonics are included in
assessing the parameter estimation problem. We show that in a subset of the
source parameter space the angular resolution increases by more than a factor
of 10, thereby making it possible for LISA to identify the host galaxy/galaxy
cluster. Thus, LISA's observation of certain binary SMBH coalescence events
could constrain the dark energy equation of state to within a few percent,
comparable to the level expected from other dark energy missions.Comment: 15 pages, no figures. Final version to appear in Phys. Rev.
TIGER: A data analysis pipeline for testing the strong-field dynamics of general relativity with gravitational wave signals from coalescing compact binaries
The direct detection of gravitational waves with upcoming second-generation
gravitational wave detectors such as Advanced LIGO and Virgo will allow us to
probe the genuinely strong-field dynamics of general relativity (GR) for the
first time. We present a data analysis pipeline called TIGER (Test
Infrastructure for GEneral Relativity), which is designed to utilize detections
of compact binary coalescences to test GR in this regime. TIGER is a
model-independent test of GR itself, in that it is not necessary to compare
with any specific alternative theory. It performs Bayesian inference on two
hypotheses: the GR hypothesis , and , which states that one or more of the post-Newtonian coefficients in
the waveform are not as predicted by GR. By the use of multiple sub-hypotheses
of , in each of which a different number of
parameterized deformations of the GR phase are allowed, an arbitrarily large
number of 'testing parameters' can be used without having to worry about a
model being insufficiently parsimonious if the true number of extra parameters
is in fact small. TIGER is well-suited to the regime where most sources have
low signal-to-noise ratios, again through the use of these sub-hypotheses.
Information from multiple sources can trivially be combined, leading to a
stronger test. We focus on binary neutron star coalescences, for which
sufficiently accurate waveform models are available that can be generated fast
enough on a computer to be fit for use in Bayesian inference. We show that the
pipeline is robust against a number of fundamental, astrophysical, and
instrumental effects, such as differences between waveform approximants, a
limited number of post-Newtonian phase contributions being known, the effects
of neutron star spins and tidal deformability on the orbital motion, and
instrumental calibration errors.Comment: 12 pages, 9 figures. Version as appears in Phys. Rev.
Determination of Dark Energy by the Einstein Telescope: Comparing with CMB, BAO and SNIa Observations
A design study is currently in progress for a third generation
gravitational-wave (GW) detector called Einstein Telescope (ET). An important
kind of source for ET will be the inspiral and merger of binary neutron stars
(BNS) up to . If BNS mergers are the progenitors of short-hard
-ray bursts, then some fraction of them will be seen both
electromagnetically and through GW, so that the luminosity distance and the
redshift of the source can be determined separately. An important property of
these `standard sirens' is that they are \emph{self-calibrating}: the
luminosity distance can be inferred directly from the GW signal, with no need
for a cosmic distance ladder. Thus, standard sirens will provide a powerful
independent check of the CDM model. In previous work, estimates were
made of how well ET would be able to measure a subset of the cosmological
parameters (such as the dark energy parameter ) it will have access to,
assuming that the others had been determined to great accuracy by alternative
means. Here we perform a more careful analysis by explicitly using the
potential Planck CMB data as prior information for these other parameters. We
find that ET will be able to constrain and with accuracies and , respectively. These results are compared
with projected accuracies for the JDEM Baryon Acoustic Oscillations project and
the SNAP Type Ia supernovae observations.Comment: 28 pages, 5 figures, 5 tables; Published Versio
Like or dislike? Adolescents’ responses to personalized social network site advertising
Increasingly, personal data posted by users of social network sites (SNSs) can be used to personalize advertising. The present study investigates how adolescents respond to personalized ads in terms of attitude toward the ad, brand engagement and intention to forward, and whether privacy concerns moderate their responses. According to pretest results, a medium level of personalization was expected to be optimal in terms of advertising effectiveness. A within-subjects experiment involving 40 participants aged 14–18 years was performed. Three conditions of personalized advertising were designed with, respectively, low, medium, and high levels of personalization. The study found that the highest personalization condition generated the most positive response and that privacy concerns did not moderate the effects of personalization. The privacy paradox is discussed as an alternative explanation, along with other implications of the results
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