Probing Gravitational Waves from Pulsars in Brans–Dicke Theory

Verma, P.

doi:10.3390/universe7070235

Cited by 10 publications

(11 citation statements)

References 31 publications

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“…The methods have been used in several analyses of LIGO and Virgo data (Abadie et al 2011;Aasi et al 2014;Abbott et al 2017aAbbott et al , 2020. The method also uses the D-statistic developed in Verma (2021) to search for dipole radiation in Brans-Dicke theory. The D-statistic search is the first search of LIGO and Virgo data for dipole radiation as predicted by Brans-Dicke theory.…”

Section: F/g/d-statistic Methodsmentioning

confidence: 99%

Searches for Gravitational Waves from Known Pulsars at Two Harmonics in the Second and Third LIGO-Virgo Observing Runs

Abbott¹,

Abe²,

Acernese³

et al. 2021

Preprint

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We present a targeted search for continuous gravitational waves (GWs) from 236 pulsars using data from the third observing run of LIGO and Virgo (O3) combined with data from the second observing run (O2). Searches were for emission from the l = m = 2 mass quadrupole mode with a frequency at only twice the pulsar rotation frequency (single harmonic) and the l = 2, m = 1, 2 modes with a frequency of both once and twice the rotation frequency (dual harmonic). No evidence of GWs was found so we present 95% credible upper limits on the strain amplitudes h 0 for the single harmonic search along with limits on the pulsars' mass quadrupole moments Q 22 and ellipticities ε. Of the pulsars studied, 23 have strain amplitudes that are lower than the limits calculated from their electromagnetically measured spin-down rates. These pulsars include the millisecond pulsars J0437−4715 and J0711−6830 which have spin-down ratios of 0.87 and 0.57 respectively. For nine pulsars, their spin-down limits have been surpassed for the first time. For the Crab and Vela pulsars our limits are factors of ∼ 100 and ∼ 20 more constraining than their spin-down limits, respectively. For the dual harmonic searches, new limits are placed on the strain amplitudes C 21 and C 22 . For 23 pulsars we also present limits on the emission amplitude assuming dipole radiation as predicted by Brans-Dicke theory.

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Section: F/g/d-statistic Methodsmentioning

confidence: 99%

Searches for Gravitational Waves from Known Pulsars at Two Harmonics in the Second and Third LIGO-Virgo Observing Runs

Abbott¹,

Abe²,

Acernese³

et al. 2021

Preprint

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“…We take note of that in our MBDT model, given that we have replaced the gravitational constant of GR with a changing gravitational field, and it could be parameterized by an inverse relationship with cosmic time based on the equivalency to the Newtonian gravitational constant as specifically described in Refs. [32,33]. As data from future multi-messenger events such as coincidental gravitational waves and electromagnetic signals from neutron star collisions, accumulates, we will hone our MBDT model's parameters to accommodate compatible with our expectations from an accelerated expanding universe.…”

Section: B Depict the Energy Conditions Derived From Mbdtmentioning

confidence: 95%

Energy conditions in a modified Brans-Dicke theory

Amani,

Halpern

2022

Preprint

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We consider a modified version of Brans-Dicke theory (MBDT) in four dimensions (4D) obtained by applying the induced matter method of Wesson to a 5D generalized Brans-Dicke theory. In 5D the model consists of pure vacuum, with no selfinteracting potential, except for a scalar field. Following Wesson's protocol, we group geometric terms in the 5D Einstein tensor arising from the extra dimension, move them to the other side of the generalized field equations, and identify them as the energy-momentum of the induced matter in 4D. Thus the extra dimension in 5D leads naturally to an effective matter field in 4D. Constraining the 5D geometry to be a generalization of the anisotropic Bianchi type I universe model first studied by Kasner, we derive the induced energy-momentum in MBDT and apply it to the investigation of energy conditions. The specified induced energy-momentum of that MBDT model consists of the energy density and directional pressure which indicate the anisotropy of the universe. We discuss the energy conditions and their bounds in the MBDT with such an induced imperfect fluid, with an eye toward a realistic model of the present-day universe, and consider the large-scale behavior of that spatially homogeneous and anisotropic model. We discuss how the energy conditions would be satisfied or violated in the context of MBDT, with the aim of providing a feasible description of the universe in the current era.

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“…Here, we present only important formulae without any derivations. For a detailed analysis, one can follow [12], [13].…”

Section: Gravitational Radiationmentioning

confidence: 99%

“…So, BD theory appears to be a good candidate to start with. Recently, we have implemented the BD theory to hunt for the dipole radiation in the LVK O3 data [11] by adding the D-statistics developed in [12].…”

Section: Introductionmentioning

confidence: 99%

Radiation from a Classical Harmonic Oscillator

Verma¹

2022

Preprint

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This article presents the calculation of gravitational and electromagnetic radiation emitted from a classical simple harmonic oscillator (SHO). Here we show only the selected formulae and apply them to a toy problem without rigorous derivation. First, we calculate the explicit expressions for the gravitational waves polarizations and then obtain the power radiated away in gravitational waves using Brans-Dicke theory (BD). We also calculate the electromagnetic dipole and quadrupole power emitted by the SHO and compare them with their gravitational counterparts.

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Probing Gravitational Waves from Pulsars in Brans–Dicke Theory

Cited by 10 publications

References 31 publications

Searches for Gravitational Waves from Known Pulsars at Two Harmonics in the Second and Third LIGO-Virgo Observing Runs

Searches for Gravitational Waves from Known Pulsars at Two Harmonics in the Second and Third LIGO-Virgo Observing Runs

Energy conditions in a modified Brans-Dicke theory

Radiation from a Classical Harmonic Oscillator

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