Pub Date : 2024-09-09DOI: 10.1088/1361-6382/ad74d3
Gilberto M Kremer
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.
{"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}
Pub Date : 2024-09-09DOI: 10.1088/1361-6382/ad708a
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
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.
{"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}
Pub Date : 2024-09-08DOI: 10.1088/1361-6382/ad7186
N Mohammedi
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.
{"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}
Pub Date : 2024-09-08DOI: 10.1088/1361-6382/ad7452
Ying Yang, Xiangyun Fu and Jiliang Jing
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.
{"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}
Pub Date : 2024-09-08DOI: 10.1088/1361-6382/ad718a
Chris Hull, Maxwell L Hutt and Ulf Lindström
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.
{"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}
Pub Date : 2024-09-05DOI: 10.1088/1361-6382/ad72ca
Xiaolin Liu, Zhoujian Cao and Zong-Hong Zhu
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.
{"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}
Pub Date : 2024-09-05DOI: 10.1088/1361-6382/ad7451
Abdel Nasser Tawfik, Antonio Pasqua, Muhammad Waqas, Azzah A Alshehri and Prabir Kr Haldar
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.
引力场（包括度量场）的量子化问题已通过环量子引力、量子场论和弦理论等多种方法进行了研究。然而，要解决将广义相对论（GR）和量子力学（QM）这两种根本不同的理论融合在一起的难题，另一种策略是采用量子几何方法。这种方法需要将量子力学扩展到相对论能量和有限引力场，同时将连续黎曼几何扩展到离散化（量子化）的芬斯勒-汉密尔顿几何。采用这种方法，也许可以弥合 GR 与 QM 之间的差距，甚至实现它们的统一。由此产生的基本张量似乎融合了其原有的经典和量子特性，有效地整合了量子力学对仿射连接和时空曲率的修正。我们的研究主要侧重于研究爱因斯坦-吉尔伯特-斯特劳斯公设背景下的里奇曲率张量。通过采用分析和数值方法，我们发现了量子条件曲率（QCC），它是引力的额外来源。这些 QCC 与爱因斯坦伽利略描述的传统曲率有着本质区别。大多数区域的利玛窦曲率主要为正，而量子化利玛窦曲率则显示为负。我们的结论是：QCC（a）具有内在的、本质的和真实的特性；（b）不应因其显著的量级而被忽视；（c）与经典 GR 中的曲率有本质区别。此外，我们还得出结论，所提出的量子几何方法可以为理解量子引力的出现提供另一种数学框架。
{"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}
Pub Date : 2024-09-04DOI: 10.1088/1361-6382/ad72cb
Balázs Kacskovics and Dániel Barta
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.
{"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}
Pub Date : 2024-09-03DOI: 10.1088/1361-6382/ad721b
Raúl Arias, Marcelo Botta-Cantcheff and Pedro J Martinez
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.
我们在萨克德夫-叶-基塔埃夫量子力学与 JT 引力的对应关系中研究了传统的全息公式及其实时扩展。我们首先观察到，只有封闭轮廓才允许有二维时空全息对偶和标准全息公式。因此，在对偶性的实时表述中，经典连通几何的边界是一组封闭曲线，其参数是施文格-凯尔迪什框架中的复时间等值线。在这种情况下，可以提出标准全息公式的一致扩展，描述引力与边界量子模型之间的（实时）对应关系，其中包括耦合常数的平均值。我们在具有施文格-凯尔迪什边界条件的不同 AdS 解决方案中研究了所提出的公式，这些解决方案与定义在复杂时间等值线上的有限温度边界量子理论是对偶的，我们还考虑了具有两个断开边界的经典渐近 AdS 解决方案（虫洞）。在此过程中，我们重温了所谓的因式分解问题，以及传统全息术中凭借断开边界之间的某种（非局部）耦合来解决这一问题的方法，并展示了在特定情况下，平均化提议如何也能绕过这一悖论，因为它诱发了类似的有效耦合。
{"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}
Pub Date : 2024-09-03DOI: 10.1088/1361-6382/ad721e
J D Simão
We propose an explicit spin-foam amplitude for Lorentzian gravity in three dimensions, allowing for both space- and time-like boundaries. The model is based on two main requirements: that it should be structurally similar to its well-known Euclidean analog, and that geometricity should be recovered in the semiclassical regime. To this end we introduce new coherent states for space-like boundary edges, derived from the continuous series of unitary representations. We show that the relevant objects in the amplitude can be written in terms of the defining representation of the group, just as so happens in the Euclidean case. We derive an expression for the semiclassical amplitude at large spins, showing it relates to the Lorentzian Regge action.
{"title":"A new 2+1 coherent spin-foam vertex for quantum gravity","authors":"J D Simão","doi":"10.1088/1361-6382/ad721e","DOIUrl":"https://doi.org/10.1088/1361-6382/ad721e","url":null,"abstract":"We propose an explicit spin-foam amplitude for Lorentzian gravity in three dimensions, allowing for both space- and time-like boundaries. The model is based on two main requirements: that it should be structurally similar to its well-known Euclidean analog, and that geometricity should be recovered in the semiclassical regime. To this end we introduce new coherent states for space-like boundary edges, derived from the continuous series of unitary representations. We show that the relevant objects in the amplitude can be written in terms of the defining representation of the group, just as so happens in the Euclidean case. We derive an expression for the semiclassical amplitude at large spins, showing it relates to the Lorentzian Regge action.","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":"142130647","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}
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