{"title":"Iterative extraction of overtones from black hole ringdown","authors":"Kazuto Takahashi and Hayato Motohashi","doi":"10.1088/1361-6382/ad72c9","DOIUrl":"https://doi.org/10.1088/1361-6382/ad72c9","url":null,"abstract":"Extraction of multiple quasinormal modes (QNMs) from ringdown gravitational waves emitted from a binary black hole coalescence is a touchstone to test whether a remnant black hole is described by the Kerr spacetime in general relativity. However, it is not straightforward to check the consistency between the ringdown signal and the QNM frequencies predicted by the linear perturbation theory. While the longest-lived mode can be extracted in a stable manner, the higher overtones damp more quickly and hence the fitting of overtones tends to end up with the overfit. To improve the extraction of overtones, we propose an iterative procedure consisting of fitting and subtraction of the longest-lived mode of the ringdown waveform in the time domain. Through the analyses of the mock waveform and numerical relativity waveform, we clarify that the iterative procedure allows us to extract the overtones in a more stable manner.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Kinetic and hydrodynamic post-Newtonian equations in the Brans–Dicke theory","authors":"Gilberto M Kremer","doi":"10.1088/1361-6382/ad74d3","DOIUrl":"https://doi.org/10.1088/1361-6382/ad74d3","url":null,"abstract":"A kinetic theory for the post-Newtonian Brans–Dicke theory is developed. The Boltzmann equation and the equilibrium Maxwell-Jüttner distribution function are determined from the knowledge of the components of the metric tensor and Christoffel symbols in the post-Newtonian Brans–Dicke theory. The hydrodynamic equations for the mass density, momentum density and mass-energy density are obtained from a transfer equation derived from the Boltzmann equation. The problem of self-gravitating fluid instabilities in the post-Newtonian Brans–Dicke theory is investigated.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muhammed Saleem, Alec Gunny, Chia-Jui Chou, Li-Cheng Yang, Shu-Wei Yeh, Andy H Y Chen, Ryan Magee, William Benoit, Tri Nguyen, Pinchen Fan, Deep Chatterjee, Ethan Marx, Eric Moreno, Rafia Omer, Ryan Raikman, Dylan Rankin, Ritwik Sharma, Michael Coughlin, Philip Harris and Erik Katsavounidis
{"title":"Demonstration of machine learning-assisted low-latency noise regression in gravitational wave detectors","authors":"Muhammed Saleem, Alec Gunny, Chia-Jui Chou, Li-Cheng Yang, Shu-Wei Yeh, Andy H Y Chen, Ryan Magee, William Benoit, Tri Nguyen, Pinchen Fan, Deep Chatterjee, Ethan Marx, Eric Moreno, Rafia Omer, Ryan Raikman, Dylan Rankin, Ritwik Sharma, Michael Coughlin, Philip Harris and Erik Katsavounidis","doi":"10.1088/1361-6382/ad708a","DOIUrl":"https://doi.org/10.1088/1361-6382/ad708a","url":null,"abstract":"Low-latency noise regression algorithms are crucial for maximizing the science outcomes of the LIGO, Virgo, and KAGRA gravitational-wave detectors. This includes improvements in the detectability, source localization and pre-merger detectability of signals thereby enabling rapid multi-messenger follow-up. In this paper, we demonstrate the effectiveness of DeepClean, a convolutional neural network architecture that uses witness sensors to estimate and subtract non-linear and non-stationary noise from gravitational-wave strain data. Our study uses LIGO data from the third observing run with injected compact binary signals. As a demonstration, we use DeepClean to subtract the noise at 60 Hz due to the power mains and their sidebands arising from non-linear coupling with other instrumental noise sources. Our parameter estimation study on the injected signals shows that DeepClean does not do any harm to the underlying astrophysical signals in the data while it can enhance the signal-to-noise ratio of potential signals. We show that DeepClean can be used for low-latency noise regression to produce cleaned output data at latencies ~1–2 s. We also discuss various considerations that may be made while training DeepClean for low latency applications.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A note on Weyl gauge symmetry in gravity","authors":"N Mohammedi","doi":"10.1088/1361-6382/ad7186","DOIUrl":"https://doi.org/10.1088/1361-6382/ad7186","url":null,"abstract":"A scale invariant theory of gravity, containing at most two derivatives, requires, in addition to the Riemannian metric, a scalar field and (or) a gauge field. The gauge field is usually used to construct the affine connection of Weyl geometry. In this note, we incorporate both the gauge field and the scalar field to build a generalised scale invariant Weyl affine connection. The Ricci tensor and the Ricci scalar made out of this generalised Weyl affine connection contain, naturally, kinetic terms for the scalar field and the gauge field. This provides a geometric interpretation for these terms. It is also shown that scale invariance in the presence of a cosmological constant and mass terms is not completely lost. It becomes a duality transformation relating various fields.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142158794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Quantum Fisher information in acceleration parallel to a planar wall","authors":"Ying Yang, Xiangyun Fu and Jiliang Jing","doi":"10.1088/1361-6382/ad7452","DOIUrl":"https://doi.org/10.1088/1361-6382/ad7452","url":null,"abstract":"In this work, we devote to understand how boundaries can help improve parameter estimation against atomic decoherence and dissipation caused by relativistic motion. The system we considered is a two-level atom in uniform linear acceleration parallel to a planar wall in (3+1)-dimensional Minkowski spacetime, which is coupled to a massless scalar field with Dirichlet, Neumann or transparent boundary conditions at the wall. We find that the quantum Fisher information (QFI), which determines the ultimate estimation precision, depends on various factors, such as atomic motional trajectories, evolution time, atomic initial state, and the boundary condition. We identify the optimal estimation strategies that maximize the QFI through all the associated parameters, thus optimizing the estimation precision. Our results show that the QFI has different behaviors and even different magnitudes for different boundary cases. We also determine the boundary conditions that can effectively suppress the influence of atomic relativistic motion on the QFI. Our investigation may help advance the study of relativistic quantum information in cavity quantum electrodynamics.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142158797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Gauge-invariant magnetic charges in linearised gravity","authors":"Chris Hull, Maxwell L Hutt and Ulf Lindström","doi":"10.1088/1361-6382/ad718a","DOIUrl":"https://doi.org/10.1088/1361-6382/ad718a","url":null,"abstract":"Linearised gravity has magnetic charges carried by (linearised) Kaluza–Klein monopoles. A gauge-invariant expression is found for these charges that is similar to Penrose’s gauge-invariant expression for the ADM charges. A systematic search is made for other gauge-invariant charges.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142158796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effective-one-body numerical-relativity waveform model for eccentric spin-precessing binary black hole coalescence","authors":"Xiaolin Liu, Zhoujian Cao and Zong-Hong Zhu","doi":"10.1088/1361-6382/ad72ca","DOIUrl":"https://doi.org/10.1088/1361-6382/ad72ca","url":null,"abstract":"Waveform models are important to gravitational wave data analysis. People recently pay much attention to the waveform model construction for eccentric binary black hole (BBH) coalescence. Several effective-one-body (EOB) Numerical-Relativity waveform models of eccentric BBH coalescence have been constructed. But none of them can treat orbit eccentricity and spin-precessing simultaneously. The current paper focuses on this problem. The authors previously have constructed waveform model for spin-aligned eccentric BBH coalescence SEOBNRE. Here we extend such waveform model to describe eccentric spin-precessing BBH coalescence. We calculate the 2PN orbital radiation-reaction forces and the instantaneous part of the decomposed waveform for a general spinning precessing BBH system in EOB coordinates. We implement these results based on our previous SEOBNRE waveform model. We have also compared our model waveforms to both SXS and RIT numerical relativity waveforms. We find good consistency between our model and numerical relativity. Based on our new waveform model, we analyze the impact of the non-perpendicular spin contributions on waveform accuracy. We find that the non-perpendicular spin contributions primarily affect the phase of the gravitational waveforms. For the current gravitational wave detectors, this contribution is not significant. The future detectors may be affected by such non-perpendicular spin contributions. More importantly our SEOBNRE waveform model, as the first theoretical waveform model to describe eccentric spin-precessing BBH coalescence, can help people to analyze orbit eccentricity and spin precession simultaneously for gravitational wave detection data.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142142517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abdel Nasser Tawfik, Antonio Pasqua, Muhammad Waqas, Azzah A Alshehri and Prabir Kr Haldar
{"title":"Quantum geometric perspective on the origin of quantum-conditioned curvatures","authors":"Abdel Nasser Tawfik, Antonio Pasqua, Muhammad Waqas, Azzah A Alshehri and Prabir Kr Haldar","doi":"10.1088/1361-6382/ad7451","DOIUrl":"https://doi.org/10.1088/1361-6382/ad7451","url":null,"abstract":"The quantization of the gravitational field, which includes the metric field, has been investigated using various methods such as loop quantum gravity, quantum field theory, and string theory. Nevertheless, an alternative strategy to tackle the challenge of merging the fundamentally different theories of general relativity (GR) and quantum mechanics (QM) is through a quantum geometric approach. This particular approach entails extending QM to relativistic energies and finite gravitational fields, while also expanding the continuous Riemann to a discretized (quantized) Finsler–Hamilton geometry. By embracing this method, it may be feasible to bridge the gap between GR and QM or even achieve their unification. The resulting fundamental tensor appears to blend its original classical and quantum characteristics, effectively integrating quantum-mechanically induced revisions to the affine connections and spacetime curvatures. Our study primarily focuses on investigating the Ricci curvature tensor in the context of the Einstein–Gilbert–Straus metric. By employing both analytical and numerical methods, we have identified quantum-conditioned curvatures (QCC) that act as additional sources of gravitation. These QCC exhibit a fundamental difference from the traditional curvatures described by Einsteinian GR. While the Ricci curvatures are predominantly positive across most regions, the quantized Ricci curvatures display negativity. We conclude that the QCC (a) possess an intrinsic, essential, and real character, (b) should not be disregarded due to their significant magnitude, and (c) are fundamentally different from the curvatures found in classical GR. Moreover, we conclude that the proposed quantum geometric approach may offer an alternative mathematical framework for understanding the emergence of quantum gravity.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142142541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comparing eccentric waveform models based on post-Newtonian and effective-one-body approaches","authors":"Balázs Kacskovics and Dániel Barta","doi":"10.1088/1361-6382/ad72cb","DOIUrl":"https://doi.org/10.1088/1361-6382/ad72cb","url":null,"abstract":"In the present study, two numerical models were compared to each other, namely the CBWaves and SEOBNRE algorithms, developed using the post-Newtonian and effective-one-body approaches, respectively, for the study of binary black holes evolving on eccentric orbits. To map the mismatch between the two models 260 000 simulations were conducted – 20 000 for non-spinning configurations and 240 000 for spinning ones—on a common grid of parameter values over the parameter space. This space is defined by the mass ratio , the gravitational mass of each component labeled by i, the corresponding spin magnitude and a constant initial orbital eccentricity e0. A comprehensive investigation was conducted to determine whether there was a discrepancy in the waveforms generated by the two codes. This entailed an in-depth analysis of the mismatch, and an extensive comparison was carried out on the outlier points between the two codes.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142138138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Raúl Arias, Marcelo Botta-Cantcheff and Pedro J Martinez
{"title":"Real-time methods in JT/SYK holography","authors":"Raúl Arias, Marcelo Botta-Cantcheff and Pedro J Martinez","doi":"10.1088/1361-6382/ad721b","DOIUrl":"https://doi.org/10.1088/1361-6382/ad721b","url":null,"abstract":"We study the conventional holographic recipes and its real-time extensions in the context of the correspondence between Sachdev–Ye–Kitaev quantum mechanics and JT gravity. We first observe that only closed contours are allowed to have a 2d space-time holographic dual and standard holographic formulas. Thus, in a real-time formulation of the duality, the boundaries of a classical connected geometry are a set of closed curves, parameterized by a complex time contour as in the Schwinger–Keldysh framework. In this context, a consistent extension of the standard holographic formulas can be proposed, describing the (real-time) correspondence between gravity and boundary quantum models that include averaging on the coupling constants. We investigate the proposed prescription in different AdS solutions with Schwinger–Keldysh boundary condition, dual to a boundary quantum theory at finite temperature defined on a complex time contour, and consider also classical, asymptotically AdS solutions (wormholes) with two disconnected boundaries. In doing this, we revisit the so-called factorization problem, and its resolution in conventional holography by virtue of some (non-local) coupling between disconnected boundaries, and we show how in specific contexts, the averaging proposal by-passes the paradox as well, since it induces a similar effective coupling.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142130598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}