If primordial black holes (PBHs) of asteroidal mass ($M_{rm PBH}in[10^{17},10^{23}]$ g) make up the entire dark matter they could be detectable through their gravitational influence in the solar system. In this work we study the perturbations that PBHs induce on the orbits of planets. Detailed numerical simulations of the solar system, embedded in a halo of primordial black holes are performed. We show that the perturbations are too small to be directly detectable with current data, challenging recent results that have ruled out PBHs as a dark matter candidate. Using the Earth-Mars system as an observational probe, we estimate that an improvement in the measurement accuracy by more than an order of magnitude is required to detect the gravitational influence of PBHs in the solar system in the foreseeable future.
{"title":"Primordial Black Holes in the Solar System","authors":"Valentin Thoss, Andreas Burkert","doi":"arxiv-2409.04518","DOIUrl":"https://doi.org/arxiv-2409.04518","url":null,"abstract":"If primordial black holes (PBHs) of asteroidal mass ($M_{rm\u0000PBH}in[10^{17},10^{23}]$ g) make up the entire dark matter they could be\u0000detectable through their gravitational influence in the solar system. In this\u0000work we study the perturbations that PBHs induce on the orbits of planets.\u0000Detailed numerical simulations of the solar system, embedded in a halo of\u0000primordial black holes are performed. We show that the perturbations are too\u0000small to be directly detectable with current data, challenging recent results\u0000that have ruled out PBHs as a dark matter candidate. Using the Earth-Mars\u0000system as an observational probe, we estimate that an improvement in the\u0000measurement accuracy by more than an order of magnitude is required to detect\u0000the gravitational influence of PBHs in the solar system in the foreseeable\u0000future.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The two most common initial data for vacuum axisymmetric spacetimes are the Brill and Teukolsky gravitational waves. The subsequent numerical evolution of these data exhibits distinct properties mainly associated with the critical gravitational collapse. A possible way of understanding these differences is first to look at the linear level, where the Brill waves have a multipolar structure, while the Teukolsky waves have a quadrupolar structure. Despite being structurally distinct at the linear and nonlinear levels, we show that these gravitational wave initial data share an unexpected similarity related to the distribution of ADM mass as a function of the initial wave's amplitude. More specifically, both configurations satisfy a nonextensive relation, commonly seen in systems governed by long range interactions.
{"title":"Similarity in the Arnowitt-Deser-Misner Mass from Brill and Teukolsky Initial Data Sets Beyond the Linear Approximation","authors":"R. F. Aranha, H. P. de Oliveira","doi":"arxiv-2409.04281","DOIUrl":"https://doi.org/arxiv-2409.04281","url":null,"abstract":"The two most common initial data for vacuum axisymmetric spacetimes are the\u0000Brill and Teukolsky gravitational waves. The subsequent numerical evolution of\u0000these data exhibits distinct properties mainly associated with the critical\u0000gravitational collapse. A possible way of understanding these differences is\u0000first to look at the linear level, where the Brill waves have a multipolar\u0000structure, while the Teukolsky waves have a quadrupolar structure. Despite\u0000being structurally distinct at the linear and nonlinear levels, we show that\u0000these gravitational wave initial data share an unexpected similarity related to\u0000the distribution of ADM mass as a function of the initial wave's amplitude.\u0000More specifically, both configurations satisfy a nonextensive relation,\u0000commonly seen in systems governed by long range interactions.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142225609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Infinitesimal light bundles on curved spacetimes can be studied via a Hamiltonian formalism, similar to the Newtonian paraxial rays. In this work, we assign a classical wave function to a thin null bundle and study its evolution equation. This is achieved via the usage of the Schr"odinger operators within a procedure analogous to the one in the semi-classical regime of quantum mechanics. The correspondence between the metaplectic operators and the symplectic phase space transformations of the geodesic deviation variables is at the core of our method. It allows for the introduction of unitary operators. We provide two solutions of the null bundle wave function which differ by their origin: (i) a point source, and (ii) a finite source. It is shown that while the former wave function includes the same information as the standard thin null bundle framework, the latter is a Gaussian beam. The Gaussianity of the intensity profile of our beam depends on the spacetime curvature and not on the random processes. We show that this beam avoids the caustics of an instantaneous wavefront. Our results are applicable for any spacetime and they can be used to model light propagation from coherent sources while averting the mathematical singularities of the standard thin null bundle formalism. This is especially relevant when estimating cosmological distances in a realistic inhomogeneous universe.
可以通过哈密顿形式主义来研究弯曲时空中的无穷小光束，类似于牛顿旁轴射线。在这项工作中，我们将一个经典波函数赋值给一个细空光束，并研究它的演化方程。这是通过使用与量子力学半经典体系类似的薛定谔算子来实现的。元折中算子与大地偏离变量的交错相空间变换之间的对应关系是我们方法的核心。我们提供了空束波函数的两种解，它们的起源不同：(i) 点源，和 (ii) 有限源。结果表明，前者的波函数包含了与标准空心束框架相同的信息，而后者则是一束高斯波。我们的光束强度曲线的高斯性取决于时空曲率，而不是随机过程。我们证明，这种光束可以避免瞬时波面的凹陷。我们的结果适用于任何时空，可用于模拟相干光源的光传播，同时避免标准薄空束形式主义的数学奇异性。这对于在现实的均质宇宙中估计宇宙学距离尤为重要。
{"title":"Paraxial wave equation of light bundles: Gaussian beams and caustic avoidance","authors":"Nezihe Uzun","doi":"arxiv-2409.04659","DOIUrl":"https://doi.org/arxiv-2409.04659","url":null,"abstract":"Infinitesimal light bundles on curved spacetimes can be studied via a\u0000Hamiltonian formalism, similar to the Newtonian paraxial rays. In this work, we\u0000assign a classical wave function to a thin null bundle and study its evolution\u0000equation. This is achieved via the usage of the Schr\"odinger operators within\u0000a procedure analogous to the one in the semi-classical regime of quantum\u0000mechanics. The correspondence between the metaplectic operators and the\u0000symplectic phase space transformations of the geodesic deviation variables is\u0000at the core of our method. It allows for the introduction of unitary operators.\u0000We provide two solutions of the null bundle wave function which differ by their\u0000origin: (i) a point source, and (ii) a finite source. It is shown that while\u0000the former wave function includes the same information as the standard thin\u0000null bundle framework, the latter is a Gaussian beam. The Gaussianity of the\u0000intensity profile of our beam depends on the spacetime curvature and not on the\u0000random processes. We show that this beam avoids the caustics of an\u0000instantaneous wavefront. Our results are applicable for any spacetime and they\u0000can be used to model light propagation from coherent sources while averting the\u0000mathematical singularities of the standard thin null bundle formalism. This is\u0000especially relevant when estimating cosmological distances in a realistic\u0000inhomogeneous universe.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"399 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research delves into the potential existence of traversable wormholes (WHs) within the framework of $f(R,mathcal{L}_m, T)$ gravity, a modification that includes the matter Lagrangian and the trace of the energy-momentum tensor with specific coupling strengths $alpha$ and $beta$. A thorough examination of WH solutions is undertaken using a constant redshift function in tandem with a linear $f(R,mathcal{L}_m, T)$ model. The analysis involves deriving WH shape functions based on non-commutative geometry, with a particular focus on Gaussian and Lorentzian matter distributions $rho$. Constraints on the coupling parameters are developed so that the shape function satisfies both the flaring-out and asymptotic flatness conditions. Moreover, for positive coupling parameters, violating the null energy condition (NEC) at the WH throat $r_0$ demands the presence of exotic matter. For negative couplings, however, we find that exotic matter can be avoided by establishing the upper bound $beta+alpha/2<-frac{1}{rho r_0^2}-8pi$. Additionally, the effects of gravitational lensing are explored, revealing the repulsive force of our modified gravity for large negative couplings. Lastly, the stability of the derived WH solutions is verified using the Tolman-Oppenheimer-Volkoff (TOV) formalism.
{"title":"Formation of stable wormhole solution with non-commutative geometry in the framework of $f(R,mathcal{L}_m, T)$ gravity","authors":"Niklas Loewer, Moreshwar Tayde, P. K. Sahoo","doi":"arxiv-2409.04172","DOIUrl":"https://doi.org/arxiv-2409.04172","url":null,"abstract":"This research delves into the potential existence of traversable wormholes\u0000(WHs) within the framework of $f(R,mathcal{L}_m, T)$ gravity, a modification\u0000that includes the matter Lagrangian and the trace of the energy-momentum tensor\u0000with specific coupling strengths $alpha$ and $beta$. A thorough examination\u0000of WH solutions is undertaken using a constant redshift function in tandem with\u0000a linear $f(R,mathcal{L}_m, T)$ model. The analysis involves deriving WH shape\u0000functions based on non-commutative geometry, with a particular focus on\u0000Gaussian and Lorentzian matter distributions $rho$. Constraints on the\u0000coupling parameters are developed so that the shape function satisfies both the\u0000flaring-out and asymptotic flatness conditions. Moreover, for positive coupling\u0000parameters, violating the null energy condition (NEC) at the WH throat $r_0$\u0000demands the presence of exotic matter. For negative couplings, however, we find\u0000that exotic matter can be avoided by establishing the upper bound\u0000$beta+alpha/2<-frac{1}{rho r_0^2}-8pi$. Additionally, the effects of\u0000gravitational lensing are explored, revealing the repulsive force of our\u0000modified gravity for large negative couplings. Lastly, the stability of the\u0000derived WH solutions is verified using the Tolman-Oppenheimer-Volkoff (TOV)\u0000formalism.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The detailed study of the strong gravitational lensing of a Kerr black hole within Quantum Einstein Gravity (QEG) is performed. We calculate the photon sphere, the deflection angle of light, and observables on the equatorial plane under the strong deflection limit in a vacuum. The presence of quantum effects reduces the radius of the photon sphere, the magnification, the position of relativistic images, and the time delays on the same side of the lens. However, it increases the strong deflection angle, the separations, and the time delays on the opposite side of the lens. By modeling M87* and Sgr A* as the Kerr black hole within QEG, we find that the time delays are more significant in M87*, while other observables are more pronounced in Sgr A*. Furthermore, we consider the influence of plasma on the gravitational lensing effect. Plasma causes an additional deflection of light, increasing the magnification, images position and the time delays, but decreasing the separations. More importantly, we calculate the time delays under the strong deflection limit in the presence of plasma, and they increase with higher plasma concentrations. Our research may help to evaluate the observational imprints left by such quantum effects in the propagation of light and the impact of plasma around black holes on gravitational lensing.
{"title":"Strong gravitational lensing in a Kerr black hole within Quantum Einstein Gravity","authors":"Chen-Hao Xie, Yu Zhang, Bo-Li Liu, Peng-Fei Duan, Yu-Li Lou","doi":"arxiv-2409.03975","DOIUrl":"https://doi.org/arxiv-2409.03975","url":null,"abstract":"The detailed study of the strong gravitational lensing of a Kerr black hole\u0000within Quantum Einstein Gravity (QEG) is performed. We calculate the photon\u0000sphere, the deflection angle of light, and observables on the equatorial plane\u0000under the strong deflection limit in a vacuum. The presence of quantum effects\u0000reduces the radius of the photon sphere, the magnification, the position of\u0000relativistic images, and the time delays on the same side of the lens. However,\u0000it increases the strong deflection angle, the separations, and the time delays\u0000on the opposite side of the lens. By modeling M87* and Sgr A* as the Kerr black\u0000hole within QEG, we find that the time delays are more significant in M87*,\u0000while other observables are more pronounced in Sgr A*. Furthermore, we consider\u0000the influence of plasma on the gravitational lensing effect. Plasma causes an\u0000additional deflection of light, increasing the magnification, images position\u0000and the time delays, but decreasing the separations. More importantly, we\u0000calculate the time delays under the strong deflection limit in the presence of\u0000plasma, and they increase with higher plasma concentrations. Our research may\u0000help to evaluate the observational imprints left by such quantum effects in the\u0000propagation of light and the impact of plasma around black holes on\u0000gravitational lensing.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"82 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zuzanna Bakun, Angelika Łukanty, Anastasiia Untilova, Adam Cieślik, Patryk Mach
We revisit the theory of timelike and null geodesics in the (extended) Kerr spacetime. This work is a sequel to a recent paper by Cie'{s}lik, Hackmann, and Mach, who applied the so-called Biermann-Weierstrass formula to integrate Kerr geodesic equations expressed in Boyer-Lindquist coordinates. We show that a formulation based on the Biermann-Weierstrass theorem can also be applied in horizon-penetrating Kerr coordinates, resulting in solutions that are smooth across Kerr horizons. Horizon-penetrating Kerr coordinates allow for an explicit continuation of timelike and null geodesics between appropriate regions of the maximal analytic extension of the Kerr spacetime. A part of this work is devoted to a graphic visualisation of such geodesics.
{"title":"Kerr Geodesics in horizon-penetrating Kerr coordinates: description in terms of Weierstrass functions","authors":"Zuzanna Bakun, Angelika Łukanty, Anastasiia Untilova, Adam Cieślik, Patryk Mach","doi":"arxiv-2409.03722","DOIUrl":"https://doi.org/arxiv-2409.03722","url":null,"abstract":"We revisit the theory of timelike and null geodesics in the (extended) Kerr\u0000spacetime. This work is a sequel to a recent paper by Cie'{s}lik, Hackmann,\u0000and Mach, who applied the so-called Biermann-Weierstrass formula to integrate\u0000Kerr geodesic equations expressed in Boyer-Lindquist coordinates. We show that\u0000a formulation based on the Biermann-Weierstrass theorem can also be applied in\u0000horizon-penetrating Kerr coordinates, resulting in solutions that are smooth\u0000across Kerr horizons. Horizon-penetrating Kerr coordinates allow for an\u0000explicit continuation of timelike and null geodesics between appropriate\u0000regions of the maximal analytic extension of the Kerr spacetime. A part of this\u0000work is devoted to a graphic visualisation of such geodesics.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rhiannon Udall, Sophie Hourihane, Simona Miller, Derek Davis, Katerina Chatziioannou, Max Isi, Howard Deshong
With a high total mass and an inferred effective spin anti-aligned with the orbital axis at the 99.9% level, GW191109 is one of the most promising candidates for a dynamical formation origin among gravitational wave events observed so far. However, the data containing GW191109 are afflicted with terrestrial noise transients, i.e., detector glitches, generated by the scattering of laser light in both LIGO detectors. We study the implications of the glitch(es) on the inferred properties and astrophysical interpretation of GW191109. Using time- and frequency-domain analysis methods, we isolate the critical data for spin inference to 35 - 40 Hz and 0.1 - 0.04 s before the merger in LIGO Livingston, directly coincident with the glitch. Using two models of glitch behavior, one tailored to slow scattered light and one more generic, we perform joint inference of the glitch and binary parameters. When the glitch is modeled as slow scattered light, the binary parameters favor anti-aligned spins, in agreement with existing interpretations. When more flexible glitch modeling based on sine-Gaussian wavelets is used instead, a bimodal aligned/anti-aligned solution emerges. The anti-aligned spin mode is correlated with a weaker inferred glitch and preferred by ~ 70 : 30 compared to the aligned spin mode and a stronger inferred glitch. We conclude that if we assume that the data are only impacted by slow scattering noise, then the anti-aligned spin inference is robust. However, the data alone cannot validate this assumption and resolve the anti-aligned spin and potentially dynamical formation history of GW191109.
{"title":"The anti-aligned spin of GW191109: glitch mitigation and its implications","authors":"Rhiannon Udall, Sophie Hourihane, Simona Miller, Derek Davis, Katerina Chatziioannou, Max Isi, Howard Deshong","doi":"arxiv-2409.03912","DOIUrl":"https://doi.org/arxiv-2409.03912","url":null,"abstract":"With a high total mass and an inferred effective spin anti-aligned with the\u0000orbital axis at the 99.9% level, GW191109 is one of the most promising\u0000candidates for a dynamical formation origin among gravitational wave events\u0000observed so far. However, the data containing GW191109 are afflicted with\u0000terrestrial noise transients, i.e., detector glitches, generated by the\u0000scattering of laser light in both LIGO detectors. We study the implications of\u0000the glitch(es) on the inferred properties and astrophysical interpretation of\u0000GW191109. Using time- and frequency-domain analysis methods, we isolate the\u0000critical data for spin inference to 35 - 40 Hz and 0.1 - 0.04 s before the\u0000merger in LIGO Livingston, directly coincident with the glitch. Using two\u0000models of glitch behavior, one tailored to slow scattered light and one more\u0000generic, we perform joint inference of the glitch and binary parameters. When\u0000the glitch is modeled as slow scattered light, the binary parameters favor\u0000anti-aligned spins, in agreement with existing interpretations. When more\u0000flexible glitch modeling based on sine-Gaussian wavelets is used instead, a\u0000bimodal aligned/anti-aligned solution emerges. The anti-aligned spin mode is\u0000correlated with a weaker inferred glitch and preferred by ~ 70 : 30 compared to\u0000the aligned spin mode and a stronger inferred glitch. We conclude that if we\u0000assume that the data are only impacted by slow scattering noise, then the\u0000anti-aligned spin inference is robust. However, the data alone cannot validate\u0000this assumption and resolve the anti-aligned spin and potentially dynamical\u0000formation history of GW191109.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a physics-inspired transformer model that predicts the non-linear dynamics of higher-order wave modes emitted by quasi-circular, spinning, non-precessing binary black hole mergers. The model forecasts the waveform evolution from the pre-merger phase through the ringdown, starting with an input time-series spanning $ t in [-5000textrm{M}, -100textrm{M}) $. The merger event, defined as the peak amplitude of waveforms that include the $l = |m| = 2$ modes, occurs at $ t = 0textrm{M} $. The transformer then generates predictions over the time range $ t in [-100textrm{M}, 130textrm{M}] $. We produced training, evaluation and test sets using the NRHybSur3dq8 model, considering a signal manifold defined by mass ratios $ q in [1, 8] $; spin components $ s^z_{{1,2}} in [-0.8, 0.8] $; modes up to $l leq 4$, including the $(5,5)$ mode but excluding the $(4,0)$ and $(4,1)$ modes; and inclination angles $theta in [0, pi]$. We trained the model on 14,440,761 waveforms, completing the training in 15 hours using 16 NVIDIA A100 GPUs in the Delta supercomputer. We used 4 H100 GPUs in the DeltaAI supercomputer to compute, within 7 hours, the overlap between ground truth and predicted waveforms using a test set of 840,000 waveforms, finding that the mean and median overlaps over the test set are 0.996 and 0.997, respectively. Additionally, we conducted interpretability studies to elucidate the waveform features utilized by our transformer model to produce accurate predictions. The scientific software used for this work is released with this manuscript.
我们提出了一个物理学启发的变压器模型，该模型预测了准环形、旋转、非预处理双黑洞合并所发射的高阶波模式的非线性动力学。该模型预测了从合并前阶段到环减阶段的波形演变，从输入时间序列开始，跨度为 $ t in [-5000textrm{M}, -100textrm{M}) $。 合并事件定义为包括 $l =|m| = 2$ 模式的波形的峰值振幅，发生在 $ t = 0textrm{M} 。然后，变换器在 [-100textrm{M}, 130textrm{M}] $ 的时间范围内生成预测。我们使用 NRHybSur3dq8 模型制作了训练集、评估集和测试集，考虑了由质量比 $ q （在 [1, 8] $ 之间）、自旋分量 $ s^z_{{1, 2}} 定义的信号流形。in [-0.8, 0.8] $; modes up to $l leq 4$, including the $(5,5)$ mode but excluding the $(4,0)$ and $(4,1)$ modes; and inclinationangles $theta in [0, pi]$.我们在14,440,761个波形上训练了模型，使用Deltas超级计算机中的16个英伟达A100 GPU在15个小时内完成了训练。我们使用 DeltaAI 超级计算机中的 4 个 H100 GPU，在 7 个小时内利用 840,000 个波形的测试集计算了地面实况与预测波形之间的重叠度，发现测试集重叠度的平均值和中位数分别为 0.996 和 0.997。此外，我们还进行了可解释性研究，以阐明我们的变压器模型利用哪些波形特征进行准确预测。这项工作所使用的科学软件随本稿一起发布。
{"title":"AI forecasting of higher-order wave modes of spinning binary black hole mergers","authors":"Victoria Tiki, Kiet Pham, Eliu Huerta","doi":"arxiv-2409.03833","DOIUrl":"https://doi.org/arxiv-2409.03833","url":null,"abstract":"We present a physics-inspired transformer model that predicts the non-linear\u0000dynamics of higher-order wave modes emitted by quasi-circular, spinning,\u0000non-precessing binary black hole mergers. The model forecasts the waveform\u0000evolution from the pre-merger phase through the ringdown, starting with an\u0000input time-series spanning $ t in [-5000textrm{M}, -100textrm{M}) $. The\u0000merger event, defined as the peak amplitude of waveforms that include the $l =\u0000|m| = 2$ modes, occurs at $ t = 0textrm{M} $. The transformer then generates\u0000predictions over the time range $ t in [-100textrm{M}, 130textrm{M}] $. We\u0000produced training, evaluation and test sets using the NRHybSur3dq8 model,\u0000considering a signal manifold defined by mass ratios $ q in [1, 8] $; spin\u0000components $ s^z_{{1,2}} in [-0.8, 0.8] $; modes up to $l leq 4$, including\u0000the $(5,5)$ mode but excluding the $(4,0)$ and $(4,1)$ modes; and inclination\u0000angles $theta in [0, pi]$. We trained the model on 14,440,761 waveforms,\u0000completing the training in 15 hours using 16 NVIDIA A100 GPUs in the Delta\u0000supercomputer. We used 4 H100 GPUs in the DeltaAI supercomputer to compute,\u0000within 7 hours, the overlap between ground truth and predicted waveforms using\u0000a test set of 840,000 waveforms, finding that the mean and median overlaps over\u0000the test set are 0.996 and 0.997, respectively. Additionally, we conducted\u0000interpretability studies to elucidate the waveform features utilized by our\u0000transformer model to produce accurate predictions. The scientific software used\u0000for this work is released with this manuscript.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qing Yang, Xiao Guo, Zhoujian Cao, Xiaoyun Shao, Xi Yuan
Several pulsar timing array (PTA) groups have recently claimed the detection of nanohertz gravitational wave (GW) background, but the origin of this GW signal remains unclear. Nanohertz GWs generated by supermassive binary black holes (SMBBHs) are one of the most important GW sources in the PTA band. Utilizing data from numerical cosmology simulation, we generate mock SMBBHs within the observable universe and treat them as PTA band GW sources. We present their statistical properties, and analyze the isotropic and anisotropic characteristics of the gravitational wave background (GWB) signal they produce. Specifically, we derive the characteristic amplitude and spectrum of the GWB signal, and calculate the angular power spectrum for both GW strains/energy density and the position distribution of GW sources. We predict that the angular power spectrum of GWB energy density has $C_1/C_0approx0.40pm0.32$, and $C_l/C_0simeq frac{1}{2(2l+1)}$ (for $l>1$). Furthermore, for the upcoming Chinese Pulsar Timing Array (CPTA) and Square Kilometre Array (SKA) PTA, we predict the spatial distribution, numbers and signal-to-noise ratio (SNR) distribution of individual GW sources that may be detected with SNR>8, and study the anisotropy property in the spatial distribution of these individual GW sources.
{"title":"Anisotropy of Nanohertz Gravitational Wave Background and Individual Sources from Supermassive Binary Black Holes: Probe of Cosmic Large Scale Structure","authors":"Qing Yang, Xiao Guo, Zhoujian Cao, Xiaoyun Shao, Xi Yuan","doi":"arxiv-2408.05043","DOIUrl":"https://doi.org/arxiv-2408.05043","url":null,"abstract":"Several pulsar timing array (PTA) groups have recently claimed the detection\u0000of nanohertz gravitational wave (GW) background, but the origin of this GW\u0000signal remains unclear. Nanohertz GWs generated by supermassive binary black\u0000holes (SMBBHs) are one of the most important GW sources in the PTA band.\u0000Utilizing data from numerical cosmology simulation, we generate mock SMBBHs\u0000within the observable universe and treat them as PTA band GW sources. We\u0000present their statistical properties, and analyze the isotropic and anisotropic\u0000characteristics of the gravitational wave background (GWB) signal they produce.\u0000Specifically, we derive the characteristic amplitude and spectrum of the GWB\u0000signal, and calculate the angular power spectrum for both GW strains/energy\u0000density and the position distribution of GW sources. We predict that the\u0000angular power spectrum of GWB energy density has $C_1/C_0approx0.40pm0.32$,\u0000and $C_l/C_0simeq frac{1}{2(2l+1)}$ (for $l>1$). Furthermore, for the\u0000upcoming Chinese Pulsar Timing Array (CPTA) and Square Kilometre Array (SKA)\u0000PTA, we predict the spatial distribution, numbers and signal-to-noise ratio\u0000(SNR) distribution of individual GW sources that may be detected with SNR>8,\u0000and study the anisotropy property in the spatial distribution of these\u0000individual GW sources.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigate the gravitational lensing by Bardeen black hole in cloud of strings (CoS) in strong field limit. The effect of CoS parameter $b$ has been outlined in comparison with Bardeen black hole lens. The impact parameter increases as we increase the CoS parameter consequently more photons approach towards lens. We also obtain magnification of relativistic images and determine relativistic Einstein rings by using the parameters of two astrophysical black hole lenses $SgrA^{*}$ and $M87^{*}$. We constrain CoS parameter of black hole using EHT observations for these black holes. We also consider the time delay of signals in the presence of CoS parameter. It is significantly measurable for supermassive black hole $M87^{*}$ than $SgrA^{*}$. This analysis would constrain the Bardeen black hole in CoS as one of the candidates of primordial gravitational lens.
我们研究了强场极限下弦云（CoS）中巴丁黑洞的引力透镜现象。与巴丁黑洞透镜相比，我们概述了CoS参数$b$的影响。随着 CoS 参数的增大，影响参数也随之增大，从而有更多的光子接近透镜。我们还利用两个天体物理黑洞透镜 $SgrA^{*}$ 和 $M87^{*}$ 的参数，获得了相对论图像的放大率，并确定了相对论爱因斯坦环。我们利用对这些黑洞的 EHT 观测来约束黑洞的 CoS 参数。我们还考虑了CoS参数存在时信号的时间延迟。与SgrA^{*}$相比，超大质量黑洞M87^{*}$的CoS参数明显可以测量。这一分析将限制CoS中的巴丁黑洞成为原初引力透镜的候选者之一。
{"title":"Strong Gravitational Lensing by Bardeen Black Hole in Cloud of Strings","authors":"Bijendra Kumar Vishvakarma, Shubham Kala, Sanjay Siwach","doi":"arxiv-2408.05018","DOIUrl":"https://doi.org/arxiv-2408.05018","url":null,"abstract":"We investigate the gravitational lensing by Bardeen black hole in cloud of\u0000strings (CoS) in strong field limit. The effect of CoS parameter $b$ has been\u0000outlined in comparison with Bardeen black hole lens. The impact parameter\u0000increases as we increase the CoS parameter consequently more photons approach\u0000towards lens. We also obtain magnification of relativistic images and determine\u0000relativistic Einstein rings by using the parameters of two astrophysical black\u0000hole lenses $SgrA^{*}$ and $M87^{*}$. We constrain CoS parameter of black hole\u0000using EHT observations for these black holes. We also consider the time delay\u0000of signals in the presence of CoS parameter. It is significantly measurable for\u0000supermassive black hole $M87^{*}$ than $SgrA^{*}$. This analysis would\u0000constrain the Bardeen black hole in CoS as one of the candidates of primordial\u0000gravitational lens.","PeriodicalId":501041,"journal":{"name":"arXiv - PHYS - General Relativity and Quantum Cosmology","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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