Classical and Quantum Gravity最新文献_第10页

A Chern-Simons approach to self-dual gravity in ( 2 + 1 ) ... （2 + 1）中自双重力的chen - simons方法…

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2025-07-27 DOI: 10.1088/1361-6382/adecd4

Prince K Osei

引用次数: 0

A compact triaxial active vibration isolator for cryogenic suspended interferometry 一种用于低温悬浮干涉测量的紧凑型三轴主动隔振器

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2025-07-27 DOI: 10.1088/1361-6382/adf0e2

S L Kranzhoff, A Bertolini, M J C Denissen, H L M M Janssen, J Lehmann, B C T van Bree, M van Dael, M Vardaro and S Hild

{"title":"A compact triaxial active vibration isolator for cryogenic suspended interferometry","authors":"S L Kranzhoff, A Bertolini, M J C Denissen, H L M M Janssen, J Lehmann, B C T van Bree, M van Dael, M Vardaro and S Hild","doi":"10.1088/1361-6382/adf0e2","DOIUrl":"https://doi.org/10.1088/1361-6382/adf0e2","url":null,"abstract":"Suspended interferometry at cryogenic temperatures down to 10–20 K requires conductive cooling in addition to radiative cooling techniques, which is challenging due to vibrations emanating from the ground and direct force perturbations from the cryogenic system potentially acting back on the seismically isolated mirrors. In this work, the passive and active isolation performance of a triaxial cryogenic active vibration isolator designed to operate at temperatures below 10 K and ultra-high vacuum conditions with pressures below 10−9 mbar is investigated. While passive isolation of ground motion is effective for frequencies above 6.5 Hz, active suppression of motion and force disturbances can be achieved between 2.46 Hz and 21.4 Hz leading to a reduction of root-mean-square motion by one order of magnitude in the active control band. The performance limits of the current system are evaluated and compared with requirements of ETpathfinder, a prototype facility for investigating cryogenic technologies that enable the target low-frequency sensitivity improvement of the planned Einstein Telescope compared to current terrestrial gravitational-wave detectors.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"145 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144715336","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}

引用次数: 0

Signal-to-noise ratio analytic formulae of the inspiral binary black holes in TianQin 天琴吸气双黑洞的信噪比解析公式

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2025-07-27 DOI: 10.1088/1361-6382/adecd9

Hong-Yu Chen, Han Wang, En-Kun Li and Yi-Ming Hu

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Constraints on the γ-parameter for the vacuum solution of Cotton gravity with geodesics and shadows 带测地线和阴影的棉花重力真空解的γ参数约束

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2025-07-27 DOI: 10.1088/1361-6382/adf0ba

Ednaldo L B Junior, José Tarciso S S Junior, Francisco S N Lobo, Manuel E Rodrigues, Diego Rubiera-Garcia, Luís F Dias da Silva and Henrique A Vieira

{"title":"Constraints on the γ-parameter for the vacuum solution of Cotton gravity with geodesics and shadows","authors":"Ednaldo L B Junior, José Tarciso S S Junior, Francisco S N Lobo, Manuel E Rodrigues, Diego Rubiera-Garcia, Luís F Dias da Silva and Henrique A Vieira","doi":"10.1088/1361-6382/adf0ba","DOIUrl":"https://doi.org/10.1088/1361-6382/adf0ba","url":null,"abstract":"We consider a recently introduced extension of General Relativity based on the use of the Cotton tensor and dubbed as Cotton gravity, to estimate the size of a new constant γ appearing within a spherically symmetric, vacuum solution of such theory. Taking into account its non-asymptotically flat character, we use the inferred size of the central brightness depression of the supermassive object at the heart of the Milky Way galaxy (Sgr A*) by the Event Horizon Telescope to constrain at 2σ) the CG parameter as . We study the potential observational consequences from the smallness of such a value using exact and numerical expressions for the deflection angle, optical images from optically and geometrically thin accretion disks, isoradials, and instability scales (Lyapunov index) of nearly bound geodesics associated to photon rings. Our results point towards the impossibility to distinguish between these two geometries using current and foreseeable techniques in the field of interferometric detection of optical sources.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"63 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144715346","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}

引用次数: 0

Relational observables in group field theory 群场论中的关系可观测值

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2025-07-24 DOI: 10.1088/1361-6382/adedf4

Luca Marchetti and Edward Wilson-Ewing

{"title":"Relational observables in group field theory","authors":"Luca Marchetti and Edward Wilson-Ewing","doi":"10.1088/1361-6382/adedf4","DOIUrl":"https://doi.org/10.1088/1361-6382/adedf4","url":null,"abstract":"We construct relational observables in group field theory (GFT) in terms of covariant positive operator-valued measures (POVMs), using techniques developed in the context of quantum reference frames (QRFs). We focus on matter QRFs; this can be generalized to other types of frames within the same POVM-based framework. The resulting family of relational observables provides a covariant framework to extract localized observables from GFT, which is typically defined in a perspective-neutral way. Then, we compare this formalism with previous proposals for relational observables in GFT. We find that our QRF-based relational observables overcome the intrinsic limitations of previous proposals while reproducing the same continuum limit results concerning expectation values of the number and volume operators on coherent states. Nonetheless, there can be important differences for more complex operators, as well as for other types of GFT states. Finally, we also use a specific class of POVMs to show how to project states and operators from the more general perspective-neutral GFT Fock space to a perspective-dependent one where a scalar matter field plays the role of a relational clock.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"75 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144701983","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}

引用次数: 0

Modulation-assisted time-delay interferometric ranging for LISA LISA的调制辅助延时干涉测距

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2025-07-24 DOI: 10.1088/1361-6382/adecd3

Jean-Baptiste Bayle, Martin Staab, Samuel P Francis, Emily Rose Rees, Robert Spero and Gerhard Heinzel

{"title":"Modulation-assisted time-delay interferometric ranging for LISA","authors":"Jean-Baptiste Bayle, Martin Staab, Samuel P Francis, Emily Rose Rees, Robert Spero and Gerhard Heinzel","doi":"10.1088/1361-6382/adecd3","DOIUrl":"https://doi.org/10.1088/1361-6382/adecd3","url":null,"abstract":"Laser Interferometer Space Antenna (LISA) represents the next frontier in gravitational-wave (GW) astronomy, targeting the detection of millihertz gravitational signals. Central to LISA’s operation is the nanosecond-precision estimation of the light travel times (LTTs) between its constituent spacecraft. Precise LTT estimates are critical for suppressing dominant laser noise with time-delay interferometry (TDI) and ensuring the required sensitivity to GW signals. The baseline method is to modulate a pseudorandom noise (PRN) code on the laser beams exchanged between the spacecraft. Time-delay interferometric ranging (TDIR) was proposed as a simpler alternative LTT estimation method. TDIR LTT estimates are chosen to minimize the TDI residual noise over the full LISA frequency band. TDIR can be used in case of PRN failure, or to calibrate the biases of the PRN method. In this study, we introduce modulation-assisted TDIR (MATDIR), an enhanced variant of TDIR that significantly improves LTT estimation precision and resilience. MATDIR achieves this by modulating the laser phase at specific frequencies, close to 1 Hz, thereby artificially elevating the laser phase content relative to secondary, unsuppressed noises. This modulation strategy not only enhances the signal-to-noise ratio for TDIR but also mitigates the impact of GW signals and instrumental artifacts, enabling more reliable LTT estimates with reduced integration times. We develop the theoretical framework of MATDIR, incorporating the full constellation of three spacecraft, laser locking, and multiple Michelson TDI combinations. Analytical predictions, confirmed by numerical simulations, indicate that MATDIR can achieve LTT estimates comparable to the 1 m-rms at of the PRN-based baseline method. We therefore suggest that the possibility to modulate lasers is added to the laser system requirements of LISA.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"15 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144701973","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}

引用次数: 0

Kerr-AdS type higher dimensional black holes with non-spherical cross-sections of horizons * 具有非球面视界截面的Kerr-AdS型高维黑洞*

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2025-07-23 DOI: 10.1088/1361-6382/adecd5

Piotr T Chruściel, Wan Cong and Finnian Gray

引用次数: 0

Thermal effective actions from conformal boundary conditions in gravity 重力共形边界条件下的热效应作用

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2025-07-22 DOI: 10.1088/1361-6382/adee72

Batoul Banihashemi, Edgar Shaghoulian and Sanjit Shashi

{"title":"Thermal effective actions from conformal boundary conditions in gravity","authors":"Batoul Banihashemi, Edgar Shaghoulian and Sanjit Shashi","doi":"10.1088/1361-6382/adee72","DOIUrl":"https://doi.org/10.1088/1361-6382/adee72","url":null,"abstract":"Recent work has studied the thermodynamics of gravity subjected to conformal boundary conditions, where the trace of the extrinsic curvature K and the conformal class of metrics are kept fixed. The case K < 0 seems tied to solutions with cosmic horizons. To study this situation further, we analyze Einstein–Maxwell theory, where we find solutions with cosmic horizons corresponding to patches inside the inner horizon of the Reissner–Nordström black hole. We find that these solutions are necessary for consistency with the thermal effective action in the putative boundary dual at O(1) chemical potential. Furthermore, we introduce a (positive or negative) cosmological constant and find more cases where solutions with cosmic horizons dominate the ensemble. Transitions between solutions with cosmic horizons and solutions with black hole horizons are mediated by ‘extremal’ solutions that correspond to patches of (A)dS , for which we discuss an effective JT gravity description with dimensionally reduced conformal boundary conditions. Finally, we introduce rotation in some simple cases and find that the bulk theory reproduces the universal velocity-dependent modification of the free energy predicted by the thermal effective action.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"110 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144684820","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}

引用次数: 0

Curvature and conformal curvature dynamics formalisms and their applications in linearized gravity 曲率和共形曲率动力学形式及其在线性化重力中的应用

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2025-07-22 DOI: 10.1088/1361-6382/adedf3

Adam Chudecki and Maciej Przanowski

引用次数: 0

superB/NRPy: scalable, task-based numerical relativity for 3G gravitational wave science superB/NRPy: 3G引力波科学的可扩展、基于任务的数值相对论

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2025-07-22 DOI: 10.1088/1361-6382/adee71

Nishita Jadoo, Terrence Pierre Jacques and Zachariah B Etienne

{"title":"superB/NRPy: scalable, task-based numerical relativity for 3G gravitational wave science","authors":"Nishita Jadoo, Terrence Pierre Jacques and Zachariah B Etienne","doi":"10.1088/1361-6382/adee71","DOIUrl":"https://doi.org/10.1088/1361-6382/adee71","url":null,"abstract":"Modern gravitational-wave science demands increasingly accurate and computationally intensive numerical relativity (NR) simulations. The Python-based, open-source NRPy framework generates optimized C/C++ code for NR, including the complete NR code BlackHoles@Home (BH@H), which leverages curvilinear coordinates well-suited to many astrophysical scenarios. Historically, BH@H was limited to single-node OpenMP CPU parallelism. To address this, we introduce superB, an open-source extension to NRPy that enables automatic generation of scalable, task-based, distributed-memory Charm++ code from existing BH@H modules. The generated code partitions the structured grids used by NRPy/BH@H, managing communication between them. Its correctness is validated through bit-identical results with the standard OpenMP version on a single node and via a head-on binary black hole simulation in cylindrical-like coordinates, accurately reproducing quasi-normal modes (up to ). The superB/NRPy-generated code demonstrates excellent strong scaling, achieving an ≈45× speedup on 64 nodes (7168 cores) compared to the original single-node OpenMP code for a large 3D vacuum test. This scalable infrastructure benefits demanding simulations and lays the groundwork for future multi-patch grid support, targeting long inspirals, extreme parameter studies, and rapid follow-ups. This infrastructure readily integrates with other NRPy/BH@H-based projects, enabling performant scaling for the general relativistic hydrodynamics code GRoovy, and facilitating future coupling with GPU acceleration via the NRPy-CUDA project.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"16 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144684819","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}

引用次数: 0