391 research outputs found
Testing the Kerr nature of intermediate-mass and supermassive black hole binaries using spin-induced multipole moment measurements
The gravitational wave measurements of spin-induced multipole moment
coefficients of a binary black hole system can be used to distinguish black
holes from other compact objects [N. V. Krishnendu et al., PRL 119, 091101
(2017)]. Here, we apply the idea proposed in [N. V. Krishnendu et al., PRL 119,
091101 (2017)] to binary systems composed of intermediate-mass and supermassive
black holes and derive the expected bounds on their Kerr nature using future
space-based gravitational wave detectors. Using astrophysical models of binary
black hole population, we study the measurability of the spin-induced
quadrupole and octupole moment coefficients using LISA and DECIGO. The errors
on spin-induced quadrupole moment parameter of the binary system are found to
be { for almost of the total supermassive binary black hole
population which is detectable by LISA whereas it is for the
intermediate-mass black hole binaries observable by DECIGO at its design
sensitivity.} We find that { errors on} {\it both} the quadrupole and octupole
moment parameters can be estimated to { be} for and {of the population} respectively for LISA and DECIGO detectors. { Our
findings suggest that a subpopulation of binary black hole events, with the
signal to noise ratio thresholds greater than 200 and 100 respectively for LISA
and DECIGO detectors, would permit tests of black hole nature to 10\%
precision.}Comment: 7 pages, 6 figure
Constraining the nature of dark compact objects with spin-induced octupole moment measurement
Various theoretical models predict the existence of exotic compact objects
that can mimic the properties of black holes (BHs). Gravitational waves (GWs)
from the mergers of compact objects have the potential to distinguish between
exotic compact objects and BHs. The measurement of spin-induced multipole
moments of compact objects in binaries provides a unique way to test the nature
of compact objects. The observations of GWs by LIGO and Virgo have already put
constraints on the spin-induced quadrupole moment, the leading order
spin-induced moment. In this work, we develop a Bayesian framework to measure
the spin-induced octupole moment, the next-to-leading order spin-induced
moment. The precise measurement of the spin-induced octupole moment will allow
us to test its consistency with that of Kerr BHs in general relativity and
constrain the allowed parameter space for non-BH compact objects. For various
simulated compact object binaries, we explore the ability of the LIGO and Virgo
detector network to constrain spin-induced octupole moment of compact objects.
We find that LIGO and Virgo at design sensitivity can constrain the symmetric
combination of component spin-induced octupole moments of binary for
dimensionless spin magnitudes . Further, we study the possibility of
simultaneously measuring the spin-induced quadrupole and octupole moments.
Finally, we perform this test on selected GW events reported in the third GW
catalog. These are the first constraints on spin-induced octupole moment using
full Bayesian analysis.Comment: 13 pages, 8 figure
Unveiling Microlensing Biases in Testing General Relativity with Gravitational Waves
Gravitational waves (GW) from chirping binary black holes (BBHs) provide
unique opportunities to test general relativity (GR) in the strong-field
regime. However, testing GR can be challenging when incomplete physical
modeling of the expected signal gives rise to systematic biases. In this study,
we investigate the potential influence of wave effects in gravitational lensing
(which we refer to as microlensing) on tests of GR using GWs for the first
time. We utilize an isolated point-lens model for microlensing with the lens
mass ranging from M and base our conclusions on an
astrophysically motivated population of BBHs in the LIGO-Virgo detector
network. Our analysis centers on two theory-agnostic tests of gravity: the
inspiral-merger-ringdown consistency test (IMRCT) and the parameterized tests.
Our findings reveal two key insights: First, microlensing can significantly
bias GR tests, with a confidence level exceeding . Notably,
substantial deviations from GR tend to align with a strong
preference for microlensing over an unlensed signal, underscoring the need for
microlensing analysis before claiming any erroneous GR deviations. Nonetheless,
we do encounter scenarios where deviations from GR remain significant (), yet the Bayes factor lacks the strength to confidently assert
microlensing. Second, deviations from GR correlate with pronounced interference
effects, which appear when the GW frequency () aligns with the
inverse time delay between microlens-induced images (). These
false deviations peak in the wave-dominated region and fade where
significantly deviates from unity. Our
findings apply broadly to any microlensing scenario, extending beyond specific
models and parameter spaces, as we relate the observed biases to the
fundamental characteristics of lensing.Comment: 21 pages, 12 figure
Antioxidant Properties of Bitter Gourd (Momordica Charantia L.)
Bitter gourd is regarded as an antioxidant rich vegetable with beneficial properties for the circulatory, respiratory, digestive and nervous systems according to the Indian indigenous system of medicine. Several methods have been used to determine antioxidant activity of plants. The present study, therefore, involved four various established methods to evaluate anti oxidative activity of bitter gourd fruit, namely, total antioxidant capacity, DPPH radical scavenging activity, hydroxyl radical scavenging activity and super oxide anion radical scavenging activity by using different types of solvents like petroleum ether, acetone, ethanol and methanol.
The present study revealed that light green big sample had the highest DPPH activity with an IC50 value of 50.88 µg/ ml in methanol solvent. In the case of bitter gourd dried samples, highest DPPH activity with an IC50 value of 50.10 µg/ ml was reported in light green big type. The hydroxyl radical scavenging activity of light green big was found to be highest both in the case of fresh and dried bitter gourd samples with an IC50 values of 50.95 µg/ml and 50.10 µg/ml respectively.
Light green small sample showed higher superoxide anion radical scavenging activity with an IC50 value of 50.36 µg/ ml in fresh samples and 49.76 µg/ ml in dried samples, in solvents like petroleum ether and acetone respectively. Antioxidant activity ranged with an IC50 value of 50.09 µg/ml to 61.90 µg/ml in fresh bitter gourd samples and maximum antioxidant capacity was observed in light green big (50.09 µg/ ml) whereas dried samples, the highest antioxidant activity was observed in light green dried (50.07 µg/ ml) in acetone solvent
Distinguishing binary black hole precessional morphologies with gravitational wave observations
The precessional motion of binary black holes can be classified into one of
three morphologies, based on the evolution of the angle between the components
of the spins in the orbital plane: Circulating, librating around 0, and
librating around . These different morphologies can be related to the
binary's formation channel and are imprinted in the binary's gravitational wave
signal. In this paper, we develop a Bayesian model selection method to
determine the preferred spin morphology of a detected binary black hole. The
method involves a fast calculation of the morphology which allows us to
restrict to a specific morphology in the Bayesian stochastic sampling. We
investigate the prospects for distinguishing between the different morphologies
using gravitational waves in the Advanced LIGO/Advanced Virgo network with
their plus-era sensitivities. For this, we consider fiducial high- and low-mass
binaries having different spin magnitudes and signal-to-noise ratios (SNRs). We
find that in the cases with high spin and high SNR, the true morphology is
strongly favored with Bayes factors compared to both
alternative morphologies when the binary's parameters are not close to the
boundary between morphologies. However, when the binary parameters are close to
the boundary between morphologies, only one alternative morphology is strongly
disfavored. In the low-spin, high-SNR cases, the true morphology is still
favored with a Bayes factor compared to one alternative
morphology. We also consider the gravitational wave signal from GW200129_065458
that has some evidence for precession (modulo data quality issues) and find
that there is no preference for a specific morphology. Our method for
restricting the prior to a given morphology is publicly available through an
easy-to-use Python package called bbh_spin_morphology_prior. (Abridged)Comment: 14 pages, 5 figures, version accepted by PR
Distinguishing binary black hole precessional morphologies with gravitational wave observations
The precessional motion of binary black holes can be classified into one of three morphologies, based on the evolution of the angle between the components of the spins in the orbital plane: Circulating, librating around 0, and librating around π. These different morphologies can be related to the binary’s formation channel and are imprinted in the binary’s gravitational wave signal. In this paper, we develop a Bayesian model selection method to determine the preferred spin morphology of a detected binary black hole. The method involves a fast calculation of the morphology which allows us to restrict to a specific morphology in the Bayesian stochastic sampling. We investigate the prospects for distinguishing between the different morphologies using gravitational waves in the Advanced LIGO/Advanced Virgo network with their plus-era sensitivities. For this, we consider fiducial high- and low-mass binaries having different spin magnitudes and signal-to-noise ratios (SNRs). We find that in the cases with high spin and high SNR, the true morphology is strongly favored with log10 Bayes factors ≳ 4 compared to both alternative morphologies when the binary’s parameters are not close to the boundary between morphologies. However, when the binary parameters are close to the boundary between morphologies, only one alternative morphology is strongly disfavored. In the low-spin, high-SNR cases, the true morphology is still favored with a log10 Bayes factor ∼ 2 compared to one alternative morphology, while in the low-SNR cases the log10 Bayes factors are at most ∼1 for many binaries. We also consider the gravitational wave signal from GW200129_065458 that has some evidence for precession (modulo data quality issues) and find that there is no preference for a specific morphology. Our method for restricting the prior to a given morphology is publicly available through an easy-to-use python package called bbh_spin_morphology_prior
Quantum chaos in the spectrum of operators used in Shor's algorithm
We provide compelling evidence for the presence of quantum chaos in the
unitary part of Shor's factoring algorithm. In particular we analyze the
spectrum of this part after proper desymmetrization and show that the
fluctuations of the eigenangles as well as the distribution of the eigenvector
components follow the CUE ensemble of random matrices, of relevance to
quantized chaotic systems that violate time-reversal symmetry. However, as the
algorithm tracks the evolution of a single state, it is possible to employ
other operators, in particular it is possible that the generic quantum chaos
found above becomes of a nongeneric kind such as is found in the quantum cat
maps, and in toy models of the quantum bakers map.Comment: Title and paper modified to include interesting additional
possibilities. Principal results unaffected. Accepted for publication in
Phys. Rev. E as Rapid Com
Population inference of spin-induced quadrupole moments as a probe for non-black hole compact binaries
Gravitational-wave (GW) measurements of physical effects such as spin-induced
quadrupole moments can distinguish binaries consisting of black holes from
non-black hole binaries. While these effects may be poorly constrained for
single-event inferences with the second-generation detectors, combining
information from multiple detections can help uncover features of non-black
hole binaries. The spin-induced quadrupole moment has specific predictions for
different types of compact objects, and a generalized formalism must consider a
population where different types of compact objects co-exist. In this study, we
introduce a hierarchical mixture-likelihood formalism to estimate the {\it
fraction of non-binary black holes in the population}. We demonstrate the
applicability of this method using simulated GW signals injected into Gaussian
noise following the design sensitivities of the Advanced LIGO Advanced Virgo
detectors. We compare the performance of this method with a
traditionally-followed hierarchical inference approach. Both the methods are
equally effective to hint at inhomogeneous populations, however, we find the
mixture-likelihood approach to be more natural for mixture populations
comprising compact objects of diverse classes. We also discuss the possible
systematics in the mixture-likelihood approach, caused by several reasons,
including the limited sensitivity of the second-generation detectors, specific
features of the astrophysical population distributions, and the limitations
posed by the waveform models employed. Finally, we apply this method to the
LIGO-Virgo detections published in the second GW transient catalog (GWTC-2) and
find them consistent with a binary black hole population within the statistical
precision.Comment: 13 pages, 6 figures, 1 tabl
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