Kristina Giesel, Andreas Leitherer and David Winnekens
{"title":"A reduced phase space quantisation of a model in algebraic quantum gravity with polarised T ...","authors":"Kristina Giesel, Andreas Leitherer and David Winnekens","doi":"10.1088/1361-6382/ae50c6","DOIUrl":"https://doi.org/10.1088/1361-6382/ae50c6","url":null,"abstract":"We consider a reduced phase space quantisation of a model with Gowdy symmetry in which gravity has been coupled to Gaussian dust. We complete the quantisation programme in reduced loop quantum gravity as well as algebraic quantum gravity (AQG) and derive a Schrödinger-like equation with a physical Hamiltonian operator encoding the dynamics. Due to the classical symmetries of the physical Hamiltonian, the operators are quantised in a graph-preserving way in both cases—a difference to former models available in the literature. As a first step towards applications of the model in AQG, we consider an ansatz that we use to first construct zero volume states as specific solutions of the Schrödiger-like equation. We then also find states with a vanishing action of the Euclidean part of the physical Hamiltonian and investigate the degeneracies these states experience via the action of the Lorentzian part of the physical Hamiltonian. The results presented here can be taken as a starting point for deriving effective models as well as analysing the dynamics numerically in future work.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"16 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147587777","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}
Shivani Harer, Maxime Vincent, Hubert Halloin, Ouali Acef, Nisrine Arab, Romain Arguel, Axel Arhancet, Damien Bachet, Nathalie Besson, Sébastien Bize, Aurélien Boutin, Sara Bruhier, Christelle Buy, Michael Carle, Jean-Pierre Coulon, Nicoleta Dinu-Jaeger, Mathieu Dupont, Christophe Fabron, Rémi Granelli, David Holleville, Dominique Huet, Pascal Huguet Chantôme, Eric Kajfasz, Mickael Lacroix, Matthieu Laporte, Rodolphe Le Targat, Jean Lesrel, Michel Lintz, Michel Lours, Christophe Meessen, Mourad Merzougui, Alexis Mehlman, Marco Nardello, Laure Oudda, Benjamin Pointard, Pierre Prat, Emmanuelle Rivière, Jérôme Royon, Aurélia Secroun, Samuel Sube, Johannes Veyron, Thomas Zerguerras and Julien Zoubian
{"title":"Validation of optical pathlength stability in a LISA test-bench demonstrator","authors":"Shivani Harer, Maxime Vincent, Hubert Halloin, Ouali Acef, Nisrine Arab, Romain Arguel, Axel Arhancet, Damien Bachet, Nathalie Besson, Sébastien Bize, Aurélien Boutin, Sara Bruhier, Christelle Buy, Michael Carle, Jean-Pierre Coulon, Nicoleta Dinu-Jaeger, Mathieu Dupont, Christophe Fabron, Rémi Granelli, David Holleville, Dominique Huet, Pascal Huguet Chantôme, Eric Kajfasz, Mickael Lacroix, Matthieu Laporte, Rodolphe Le Targat, Jean Lesrel, Michel Lintz, Michel Lours, Christophe Meessen, Mourad Merzougui, Alexis Mehlman, Marco Nardello, Laure Oudda, Benjamin Pointard, Pierre Prat, Emmanuelle Rivière, Jérôme Royon, Aurélia Secroun, Samuel Sube, Johannes Veyron, Thomas Zerguerras and Julien Zoubian","doi":"10.1088/1361-6382/ae5205","DOIUrl":"https://doi.org/10.1088/1361-6382/ae5205","url":null,"abstract":"The Laser Interferometer Space Antenna (LISA) observatory is a future L3 mission of the European Space Agency to detect gravitational waves, set to launch in 2035. The detector constellation will conduct interferometry to extreme precision over an unprecedented armlength of 2.5 million kms. In this paper, we present the development and testing results for the Zerodur interferometer (ZIFO), an optical demonstrator built to validate critical technology for the test setup of LISA’s interferometric core. Optical pathlength stability measurements on the ZIFO demonstrate successful reduction of bench noise to maintain the 10 pm specification across the 1 mHz to 1 Hz frequency band. We also identify and characterize dominant noise sources from phasemeters and correlations of beam tilt into the pathlength that are observed during the test campaign.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"46 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147587778","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":"Plasma modified black hole shadows and weak gravitational lensing of Einstein–Maxwell-dilaton spacetimes: constraints from the EHT","authors":"K Ghaderi","doi":"10.1088/1361-6382/ae49da","DOIUrl":"https://doi.org/10.1088/1361-6382/ae49da","url":null,"abstract":"We study observational signatures of Einstein–Maxwell-dilaton (EMD) black holes embedded in a cold, isotropic, dispersive plasma. Within geometric optics, we incorporate homogeneous and stratified plasma profiles to assess their impact on photon sphere location, shadow size, and weak gravitational lensing. The shadow radius shrinks monotonically with increasing plasma strength despite an outward photon sphere shift; at fixed dilaton coupling, larger charge suppresses the shadow, whereas stronger dilaton coupling enlarges it. Comparing predictions with Event Horizon Telescope measurements of M87* and Sgr A*, we infer contiguous, model dependent ranges of plasma strength consistent with current bounds on ring size and asymmetry. In the weak field limit, dispersion enhances light deflection and increases the effective Einstein angle, total magnification, and image parity fractions. These shadow lensing trends delineate EMD parameter space compatible with present data and motivate targeted, multi frequency tests.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"59 2 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147587896","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}
Estuti Shukla, Alireza Rashti, Rossella Gamba, David Radice and Koustav Chandra
{"title":"GR-Athena++ simulations of spinning binary black hole mergers","authors":"Estuti Shukla, Alireza Rashti, Rossella Gamba, David Radice and Koustav Chandra","doi":"10.1088/1361-6382/ae4da4","DOIUrl":"https://doi.org/10.1088/1361-6382/ae4da4","url":null,"abstract":"We present the second release of the GR-Athena++ waveform catalog, comprising four new quasi-circular, non-precessing, spinning binary black hole simulations. These simulations are performed at high resolutions and represent a step toward generating high-fidelity gravitational waveforms that can eventually meet the accuracy requirements of upcoming next-generation detectors, including LISA, cosmic explorer, and Einstein Telescope. Gravitational waves are extracted at future null infinity ( ) using both Cauchy characteristic extraction and finite-radius extraction. For each simulation, we provide strain data across multiple resolutions and analyze waveform accuracy via convergence studies and self-mismatch analyses. The absolute phase and relative amplitude differences reach their largest values near the merger, while the smallest errors are of order and , respectively. A self-mismatch analysis of the dominant (2, 2) mode yields mismatches between and for a total binary mass of over the frequency range using LISA’s noise curve. All waveforms are publicly available via ScholarSphere.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"275 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147536534","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":"Straight and wiggly cosmic strings in Horndeski theory","authors":"M Haluk Seçuk and Özgür Delice","doi":"10.1088/1361-6382/ae5207","DOIUrl":"https://doi.org/10.1088/1361-6382/ae5207","url":null,"abstract":"In this article, the behavior of a straight cosmic string is studied for the linearized version of Horndeski theory in cases where the scalar field is massless or massive. Several physical properties of such solutions are discussed in detail regarding the effects of the scalar field of this theory. The mass of the scalar field induces a screening effect such that, in the massive theory, the string solution approaches to the general relativistic one. We also consider wiggly cosmic strings, obtain the solutions for both massless and massive cases, discuss their properties and observe similar screening effects.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"148 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147536535","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":"Constraints and detection capabilities of GW polarizations with space-based detectors in different TDI combinations","authors":"Jie Wu, 洁 吴, Mengfei Sun, 孟飞 孙, Jin Li and 瑾 李","doi":"10.1088/1361-6382/ae5144","DOIUrl":"https://doi.org/10.1088/1361-6382/ae5144","url":null,"abstract":"Time-delay interferometry (TDI) is essential in space-based gravitational wave (GW) detectors, effectively reducing laser noise and improving detection precision. Space-based GW detectors provide a unique opportunity to probe GW polarizations, including possible additional modes that may signal deviations from general relativity and alternative gravity theories. In this study, we examine the impacts of second-generation TDI combinations on GW polarization detection by simulating LISA, Taiji, and TianQin, including realistic orbital effects such as link length and angle variations. Detector performance is assessed using sensitivity and power-law integrated curves, as well as the signal-to-noise ratio (SNR) of binary black holes (BBHs) and phase transitions (PTs). For massive BBHs, the and channels typically offer the best sensitivity, while the X channel in TianQin is most effective for detecting additional polarizations. For stellar-mass BBHs, the α channel provides the highest SNR for vector modes in LISA and Taiji specifically for lower-mass systems, while the and channels are optimal for higher masses or other polarizations. For PT signals, the X channel generally delivers the optimal performance, except in the low-peak-frequency regime below 1 mHz, where the U channel in TianQin becomes more sensitive. When considering additional polarizations, the X channel emerges as the most robust choice for TianQin, in contrast to LISA and Taiji, where the and channels provide strong capabilities for GW polarization tests. This distinction between LISA, Taiji, and TianQin represents a key result of the present work and has not been explicitly emphasized in previous studies. Our findings emphasize the importance of selecting high-sensitivity TDI combinations to enhance detection capabilities across different polarizations, deepening our insight into GW sources and the fundamental nature of spacetime.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"109 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147519263","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":"Spherical symmetric fields on torsion-free Palatini Gauss–Bonnet theory","authors":"Máximo Bañados and Daniela Bennett","doi":"10.1088/1361-6382/ae5164","DOIUrl":"https://doi.org/10.1088/1361-6382/ae5164","url":null,"abstract":"The Gauss–Bonnet density ‘a la Palatini’ is not a total derivative in four dimensions. We study spherically symmetric fields for the torsion-free theory. The resulting equations are highly complicated but we show the existence of unexpected hidden gauge symmetries, beyond diffeomorphisms and Weyl transformations.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"14 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147506882","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":"Characterization of the temperature dependence of the quality factor of a silicon substrate using the gentle nodal suspension method","authors":"Damiano Aisa, Nicolò Baldicchi, Piero Chessa, Mateusz Bawaj, Francesco Bianchi, Gabriele Capoccia, Antonfranco Piluso, Toshikazu Suzuki, Takayuki Tomaru, Flavio Travasso, Takafumi Ushiba and Helios Vocca","doi":"10.1088/1361-6382/ae50a5","DOIUrl":"https://doi.org/10.1088/1361-6382/ae50a5","url":null,"abstract":"In this work, we present the proof of concept of a characterization of the temperature dependence of the quality factor Q(T) for a massive silicon substrate suspended in a cryogenic environment using the gentle nodal suspension (GeNS) method. Measurements were conducted in a low-vibration cryostat, analyzing three distinct resonant vibrational modes of the sample. Quality factor values and associated uncertainties were extracted using multiple statistical approaches. The results highlight the suitability of the experimental method and confirm crystalline silicon as a promising material for test masses in cryogenic conditions, as required in next-generation gravitational wave detectors. A comparison between experimental data and finite element simulations confirms the accuracy of the setup. This study, part of the broader development of monolithic silicon suspensions, demonstrates the effectiveness of the GeNS technique for assessing mechanical dissipation in large-scale substrates.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"16 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147506870","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":"Estimation of the Hubble parameter from unedited compact object merger catalogues","authors":"Reiko Harada, Heather Fong and Kipp Cannon","doi":"10.1088/1361-6382/ae5208","DOIUrl":"https://doi.org/10.1088/1361-6382/ae5208","url":null,"abstract":"In recent years, constraints on the Hubble parameter using multiple dark sirens have been made, relying on a galaxy catalogue, correlations between the mass and redshift distributions, or both. Those studies have typically used only significant gravitational wave candidates. In this work, we present a framework for cosmological inference that bypasses per-candidate parameter estimation, uses only detection-level information. This allows the population inference from a candidate list produced directly by a search pipeline, without additional selection cuts. Our method is particularly suited to extracting information from marginal candidates, which are essential for probing the distant Universe. The goal of this work is not to present a constraint of the Hubble constant at this time, our primary goal is to explain the framework. To this end we present worked examples of the application of the technique to synthetic data to exhibit its performance and the novel challenges it brings.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"59 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147506871","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 comment on boundary correlators: soft omissions and the massless S-matrix","authors":"Eivind Jørstad and Sabrina Pasterski","doi":"10.1088/1361-6382/ae4da3","DOIUrl":"https://doi.org/10.1088/1361-6382/ae4da3","url":null,"abstract":"We revisit the extrapolate dictionary for massless scattering in flat spacetimes and identify a soft contribution that is typically dropped from the saddle point approximation. We show how to consistently regulate the extrapolation to include both the soft and hard components and identify the boundary correlation functions as a combination of electric and magnetic branch Carrollian correlators. This implies in particular that there are contributions to these boundary correlators that are non-distributional on the celestial sphere. Finally, we close by exploring the utility of the magnetic branch for extracting celestial data from low point correlators: connecting our results to recent work on flat space extrapolate dictionaries and celestial shadow amplitudes.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"16 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147506872","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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