Pub Date : 2025-12-18DOI: 10.1088/1361-6382/ae2735
Juliano C S Neves
The Deser–Woodard gravity is a modified theory of gravity in which nonlocality plays a central role. In this context, nonlocality is a consequence of the inverse of the d’Alembertian operator in the effective action. Here, exact black hole and wormhole solutions are built in the revised Deser–Woodard gravity following a recent approach, where a special tetrad frame simplifies the complicated field equations of the theory. Using the Schwarzschild metric and the Reissner–Nordström metric as initial seed solutions, the developed algorithm generates new traversable wormholes, singular black holes and a regular black hole as solutions of the vacuum field equations of the modified theory. Also, the auxiliary fields, which are responsible for the nonlocality, are computed. However, even for a regular black hole solution, in which spacetime does not contain a curvature singularity, the corresponding auxiliary fields diverge at the event horizon. Regarding observational results, the shadow angular radius is computed for the new solutions. In particular, the deviation of the Schwarzschild black hole in the Deser–Woodard gravity casts a larger shadow than the corresponding black hole in general relativity.
{"title":"Black holes and wormholes in Deser–Woodard gravity","authors":"Juliano C S Neves","doi":"10.1088/1361-6382/ae2735","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2735","url":null,"abstract":"The Deser–Woodard gravity is a modified theory of gravity in which nonlocality plays a central role. In this context, nonlocality is a consequence of the inverse of the d’Alembertian operator in the effective action. Here, exact black hole and wormhole solutions are built in the revised Deser–Woodard gravity following a recent approach, where a special tetrad frame simplifies the complicated field equations of the theory. Using the Schwarzschild metric and the Reissner–Nordström metric as initial seed solutions, the developed algorithm generates new traversable wormholes, singular black holes and a regular black hole as solutions of the vacuum field equations of the modified theory. Also, the auxiliary fields, which are responsible for the nonlocality, are computed. However, even for a regular black hole solution, in which spacetime does not contain a curvature singularity, the corresponding auxiliary fields diverge at the event horizon. Regarding observational results, the shadow angular radius is computed for the new solutions. In particular, the deviation of the Schwarzschild black hole in the Deser–Woodard gravity casts a larger shadow than the corresponding black hole in general relativity.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"6 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771424","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 : 2025-12-18DOI: 10.1088/1361-6382/ae2736
E Minguzzi
The properties of the stable distance over stable spacetimes are used as a reference to propose a simplified, abstract notion of spacetime. Our analysis establishes that the fundamental structures of spacetime, namely its topology, causal order, and (upper semi-continuous) Lorentzian distance, can be derived from a general and minimalistic set of axioms. Specifically, it is shown that spacetime can be represented as nothing more than a family of functions defined over an arbitrary set, the functions being a posteriori interpreted as rushing time functions. The proof makes use of the product trick which reduces causality and metricity to causality in a space with one additional dimension, so leading to a unification for the notions of time function and proper time. Ultimately, our results show that time fully characterizes spacetime.
{"title":"The representation of spacetime through time functions","authors":"E Minguzzi","doi":"10.1088/1361-6382/ae2736","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2736","url":null,"abstract":"The properties of the stable distance over stable spacetimes are used as a reference to propose a simplified, abstract notion of spacetime. Our analysis establishes that the fundamental structures of spacetime, namely its topology, causal order, and (upper semi-continuous) Lorentzian distance, can be derived from a general and minimalistic set of axioms. Specifically, it is shown that spacetime can be represented as nothing more than a family of functions defined over an arbitrary set, the functions being a posteriori interpreted as rushing time functions. The proof makes use of the product trick which reduces causality and metricity to causality in a space with one additional dimension, so leading to a unification for the notions of time function and proper time. Ultimately, our results show that time fully characterizes spacetime.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"27 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771425","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 : 2025-12-18DOI: 10.1088/1361-6382/ae272f
Tahereh Azizi and Mojtaba Alimoradi
We study a thick brane scenario within the Palatini formulation of gravity, where the metric and affine connection are treated as independent variables. By introducing a non-minimal coupling between a bulk scalar field and the Ricci scalar, we obtain analytic solutions under a flat, four-dimensional Poincaré-invariant metric with a kink-like scalar configuration. The warp factor exhibits a bell-shaped profile, while the scalar potential forms a symmetric volcano-like structure, characteristic of a finite-thickness brane. The corresponding energy density is regular and localized, featuring a central peak with symmetrically placed negative minima. Through the analysis of linear tensor perturbations, we derive a Schrödinger-like equation with supersymmetric factorization, ensuring the absence of tachyonic modes and thus the stability of the background configuration. The effective potential also takes a volcano-like form that supports a localized graviton zero mode, confirming the recovery of four-dimensional gravity on the brane. A numerical study of the massive Kaluza–Klein spectrum reveals the progressive delocalization of massive modes into the bulk. Our results demonstrate a stable and physically consistent thick brane configuration within the Palatini gravity framework, offering new insights into gravity localization and braneworld phenomenology.
{"title":"Thick brane in Palatini formalism with a non-minimally coupled bulk scalar field","authors":"Tahereh Azizi and Mojtaba Alimoradi","doi":"10.1088/1361-6382/ae272f","DOIUrl":"https://doi.org/10.1088/1361-6382/ae272f","url":null,"abstract":"We study a thick brane scenario within the Palatini formulation of gravity, where the metric and affine connection are treated as independent variables. By introducing a non-minimal coupling between a bulk scalar field and the Ricci scalar, we obtain analytic solutions under a flat, four-dimensional Poincaré-invariant metric with a kink-like scalar configuration. The warp factor exhibits a bell-shaped profile, while the scalar potential forms a symmetric volcano-like structure, characteristic of a finite-thickness brane. The corresponding energy density is regular and localized, featuring a central peak with symmetrically placed negative minima. Through the analysis of linear tensor perturbations, we derive a Schrödinger-like equation with supersymmetric factorization, ensuring the absence of tachyonic modes and thus the stability of the background configuration. The effective potential also takes a volcano-like form that supports a localized graviton zero mode, confirming the recovery of four-dimensional gravity on the brane. A numerical study of the massive Kaluza–Klein spectrum reveals the progressive delocalization of massive modes into the bulk. Our results demonstrate a stable and physically consistent thick brane configuration within the Palatini gravity framework, offering new insights into gravity localization and braneworld phenomenology.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"23 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771422","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 : 2025-12-18DOI: 10.1088/1361-6382/ae2733
Guan-Yu Wu, Si-Yu Wang and Yan-Gang Miao
Phantom scalar fields, as a viable candidate for dark energy, have been instrumental in eliminating spacetime singularities and constructing wormholes and regular black holes. We investigate the Einstein–Maxwell–phantom (EMP) framework, in which the Ellis–Bronnikov wormholes can be charged and regular black holes can be admitted. While the previous study has shown the stability of EMP wormholes under massless scalar field perturbations, we further perform a comprehensive linear analysis of the EMP spacetime through gravito-electromagnetic field perturbations in the axial sector and phantom scalar field perturbations under an approximate treatment in the polar sector. Our analyses of effective potentials and finite difference time profiles reveal the linear instability of EMP wormholes. In the black hole scenario, the quasinormal spectra of Type I black holes, where the matrix-valued direct integration method and the Prony method are used, recover those of general relativity (GR) when the scalar charge goes to zero. Finally, by introducing the concepts of generalized specific charge and mixing angle, we quantify how the relative contributions between the phantom scalar and the electromagnetic fields modify the quasinormal spectra, and we assess the prospects for detecting spectral deviations between the EMP theory and GR in gravitational wave observation.
{"title":"Perturbations of Einstein–Maxwell–phantom spacetime: instabilities of charged Ellis–Bronnikov wormholes and quasinormal modes of black holes","authors":"Guan-Yu Wu, Si-Yu Wang and Yan-Gang Miao","doi":"10.1088/1361-6382/ae2733","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2733","url":null,"abstract":"Phantom scalar fields, as a viable candidate for dark energy, have been instrumental in eliminating spacetime singularities and constructing wormholes and regular black holes. We investigate the Einstein–Maxwell–phantom (EMP) framework, in which the Ellis–Bronnikov wormholes can be charged and regular black holes can be admitted. While the previous study has shown the stability of EMP wormholes under massless scalar field perturbations, we further perform a comprehensive linear analysis of the EMP spacetime through gravito-electromagnetic field perturbations in the axial sector and phantom scalar field perturbations under an approximate treatment in the polar sector. Our analyses of effective potentials and finite difference time profiles reveal the linear instability of EMP wormholes. In the black hole scenario, the quasinormal spectra of Type I black holes, where the matrix-valued direct integration method and the Prony method are used, recover those of general relativity (GR) when the scalar charge goes to zero. Finally, by introducing the concepts of generalized specific charge and mixing angle, we quantify how the relative contributions between the phantom scalar and the electromagnetic fields modify the quasinormal spectra, and we assess the prospects for detecting spectral deviations between the EMP theory and GR in gravitational wave observation.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"5 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771423","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 : 2025-12-18DOI: 10.1088/1361-6382/ae28ac
Juan Wang, Keqi Qi, Heshan Liu, Pan Li, Ruihong Gao, Shaoxin Wang and Ziren Luo
This paper presents an integrated fiber phase modulation device (FPMD) to suppress front-end optical path difference (OPD) noise in heterodyne interferometry systems, particularly addressing noise induced by acoustic-optic modulator sideband coupling. To achieve real-time optical path stabilization, the FPMD employs a polarization-maintaining fiber coupled with piezoelectric ceramics in a monolithic aluminum structure. The compact, all-fiber design offers enhanced immunity to environmental disturbances while simplifying integration into precision interferometric systems. Through systematic characterization, the FPMD exhibits a highly linear response ( nm V−1, R2 = 0.99914) and effective noise suppression in the critical sub-10 mHz frequency band, achieving picometer-level ranging accuracy across the entire frequency band above 2 mHz. This work provides a theoretical framework and experimental validation for a robust solution to OPD noise in ultra-high-precision metrology applications.
{"title":"An integrated fiber phase modulation device for optical path noise suppression","authors":"Juan Wang, Keqi Qi, Heshan Liu, Pan Li, Ruihong Gao, Shaoxin Wang and Ziren Luo","doi":"10.1088/1361-6382/ae28ac","DOIUrl":"https://doi.org/10.1088/1361-6382/ae28ac","url":null,"abstract":"This paper presents an integrated fiber phase modulation device (FPMD) to suppress front-end optical path difference (OPD) noise in heterodyne interferometry systems, particularly addressing noise induced by acoustic-optic modulator sideband coupling. To achieve real-time optical path stabilization, the FPMD employs a polarization-maintaining fiber coupled with piezoelectric ceramics in a monolithic aluminum structure. The compact, all-fiber design offers enhanced immunity to environmental disturbances while simplifying integration into precision interferometric systems. Through systematic characterization, the FPMD exhibits a highly linear response ( nm V−1, R2 = 0.99914) and effective noise suppression in the critical sub-10 mHz frequency band, achieving picometer-level ranging accuracy across the entire frequency band above 2 mHz. This work provides a theoretical framework and experimental validation for a robust solution to OPD noise in ultra-high-precision metrology applications.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"12 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771426","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 : 2025-12-18DOI: 10.1088/1361-6382/ae2730
Marcos V de S Silva, T M Crispim, G Alencar, R R Landim and Manuel E Rodrigues
In this work, following our recent findings in Alencar et al (2025 Phys. Dark Universe49 102060), we extend our analysis to explore the generalization of spherically symmetric and static black-bounce (BB) solutions, known from General Relativity, within the framework of the f(R) theory in the metric formalism. We develop a general approach to determine the sources for any model where , provided that the corresponding source for the bounce metric in General Relativity is known. As a result, we demonstrate that BB solutions can emerge from this theory when considering the coupling of f(R) gravity with nonlinear electrodynamics and a partially phantom scalar field. We also analyzed the energy conditions of these solutions and found that, unlike in General Relativity, it is possible to satisfy all energy conditions in certain regions of space-time.
{"title":"Generalized black-bounces solutions in f(R) gravity and their field sources","authors":"Marcos V de S Silva, T M Crispim, G Alencar, R R Landim and Manuel E Rodrigues","doi":"10.1088/1361-6382/ae2730","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2730","url":null,"abstract":"In this work, following our recent findings in Alencar et al (2025 Phys. Dark Universe49 102060), we extend our analysis to explore the generalization of spherically symmetric and static black-bounce (BB) solutions, known from General Relativity, within the framework of the f(R) theory in the metric formalism. We develop a general approach to determine the sources for any model where , provided that the corresponding source for the bounce metric in General Relativity is known. As a result, we demonstrate that BB solutions can emerge from this theory when considering the coupling of f(R) gravity with nonlinear electrodynamics and a partially phantom scalar field. We also analyzed the energy conditions of these solutions and found that, unlike in General Relativity, it is possible to satisfy all energy conditions in certain regions of space-time.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"20 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771427","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 : 2025-12-17DOI: 10.1088/1361-6382/ae2412
Satadal Datta and Uwe R Fischer
Addressing the general question whether Penrose-type singularities physically exist inside black holes, we investigate the problem in the context of an analogue system, a flowing laboratory liquid, for which the governing equations are at least in principle known to all relevant scales, and in all regions of the effective spacetime. We suggest to probe the physical phenomena taking place close to the singularity in the interior of a 2+1D analogue black hole arising from a polytropic, inviscid, irrotational, and axisymmetric steady flow. Showing also that previously studied analogue black holes were not proven to contain a Penrose-type singularity, we propose an experimental setup in a Bose–Einstein condensate that allows us for the first time to verify the occurrence of the Penrose-type singularity in a physical system. Our study, in addition, provides concrete evidence, for a well understood dynamical system, that the Einstein equations are not necessary for the singularity to form, demonstrating that Penrose-type spacetime singularities can potentially also exist in non-Einsteinian theories of gravity. Finally, we demonstrate how the singularity is physically avoided in our proposed laboratory setup.
{"title":"Probing Penrose-type singularities inside sonic black holes","authors":"Satadal Datta and Uwe R Fischer","doi":"10.1088/1361-6382/ae2412","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2412","url":null,"abstract":"Addressing the general question whether Penrose-type singularities physically exist inside black holes, we investigate the problem in the context of an analogue system, a flowing laboratory liquid, for which the governing equations are at least in principle known to all relevant scales, and in all regions of the effective spacetime. We suggest to probe the physical phenomena taking place close to the singularity in the interior of a 2+1D analogue black hole arising from a polytropic, inviscid, irrotational, and axisymmetric steady flow. Showing also that previously studied analogue black holes were not proven to contain a Penrose-type singularity, we propose an experimental setup in a Bose–Einstein condensate that allows us for the first time to verify the occurrence of the Penrose-type singularity in a physical system. Our study, in addition, provides concrete evidence, for a well understood dynamical system, that the Einstein equations are not necessary for the singularity to form, demonstrating that Penrose-type spacetime singularities can potentially also exist in non-Einsteinian theories of gravity. Finally, we demonstrate how the singularity is physically avoided in our proposed laboratory setup.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"1 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771428","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 : 2025-12-16DOI: 10.1088/1361-6382/ae19c2
G M Shaifullah
This review summarises recent progress in pulsar timing array research and the current status of nanohertz gravitational wave astronomy. I outline the techniques enabling decade-long, sub-microsecond-precision timing, present results from PTA collaborations between 2023–2025, and discuss their implications for supermassive black-hole binaries, cosmological sources, and beyond-Standard-Model physics. I also highlight complimentary efforts probing the nanohertz regime.
{"title":"Pulsar timing arrays-challenges, and current status","authors":"G M Shaifullah","doi":"10.1088/1361-6382/ae19c2","DOIUrl":"https://doi.org/10.1088/1361-6382/ae19c2","url":null,"abstract":"This review summarises recent progress in pulsar timing array research and the current status of nanohertz gravitational wave astronomy. I outline the techniques enabling decade-long, sub-microsecond-precision timing, present results from PTA collaborations between 2023–2025, and discuss their implications for supermassive black-hole binaries, cosmological sources, and beyond-Standard-Model physics. I also highlight complimentary efforts probing the nanohertz regime.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"10 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760217","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 : 2025-12-15DOI: 10.1088/1361-6382/ae24da
Jamil Assaad and Rodrigo Panosso Macedo
We revisit the computation of quasinormal modes (QNMs) of the Kerr black hole using a numerical approach exploiting a representation of the Teukolsky equation as a 2D elliptic partial differential equation. By combining the hyperboloidal framework with a m-mode decomposition, we recast the QNM problem into a single eigenvalue problem for each azimuthal mode. This formulation enables the simultaneous extraction of multiple QNMs, traditionally labeled by overtone number n and angular index , without requiring prior assumptions about their structure. We advocate for a simplified notation in which each overtone is uniquely labeled by a single index q, thereby avoiding the conventional but artificial distinction between regular and mirror modes. We compare two distinct hyperboloidal gauges–radial fixing and Cauchy horizon fixing-and demonstrate that, despite their different geometric properties and behavior in the extremal limit, they yield numerical values for the QNM spectra with comparable accuracy and exponential convergence. Moreover, we show that strong gradients observed near the horizon in the extremal Kerr regime are coordinate artefacts of specific slicing rather than physical features. Finally, we investigate the angular structure of the QNM eigenfunctions and show that the m-mode approach allows flexible projection onto both spin-weighted spheroidal and spherical harmonic bases. These results underscore the robustness and versatility of the hyperboloidal m-mode method as a foundation for future studies of QNM stability, pseudospectra, and mode excitation in gravitational wave astronomy.
{"title":"Quasinormal modes in Kerr spacetime as a 2D eigenvalue problem","authors":"Jamil Assaad and Rodrigo Panosso Macedo","doi":"10.1088/1361-6382/ae24da","DOIUrl":"https://doi.org/10.1088/1361-6382/ae24da","url":null,"abstract":"We revisit the computation of quasinormal modes (QNMs) of the Kerr black hole using a numerical approach exploiting a representation of the Teukolsky equation as a 2D elliptic partial differential equation. By combining the hyperboloidal framework with a m-mode decomposition, we recast the QNM problem into a single eigenvalue problem for each azimuthal mode. This formulation enables the simultaneous extraction of multiple QNMs, traditionally labeled by overtone number n and angular index , without requiring prior assumptions about their structure. We advocate for a simplified notation in which each overtone is uniquely labeled by a single index q, thereby avoiding the conventional but artificial distinction between regular and mirror modes. We compare two distinct hyperboloidal gauges–radial fixing and Cauchy horizon fixing-and demonstrate that, despite their different geometric properties and behavior in the extremal limit, they yield numerical values for the QNM spectra with comparable accuracy and exponential convergence. Moreover, we show that strong gradients observed near the horizon in the extremal Kerr regime are coordinate artefacts of specific slicing rather than physical features. Finally, we investigate the angular structure of the QNM eigenfunctions and show that the m-mode approach allows flexible projection onto both spin-weighted spheroidal and spherical harmonic bases. These results underscore the robustness and versatility of the hyperboloidal m-mode method as a foundation for future studies of QNM stability, pseudospectra, and mode excitation in gravitational wave astronomy.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"56 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145753087","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 : 2025-12-12DOI: 10.1088/1361-6382/ae1c8c
D Serrano, A Pérez-Ortega, D Roma-Dollase, J Salvans-Tort, J J Ho-Zhang, J Ramos-Castro and M Nofrarias
The LISA mission will be the first observatory to detect gravitational waves from space within the millihertz frequency band. Magnetic forces have an important impact on the instrument’s sensitivity below the millihertz. Hence, monitoring the magnetic environment within each of the LISA spacecrafts is of utmost importance. In this Letter we present the characterization of the coils that were used in LISA Pathfinder (LPF) when operating as magnetic sensors in the audio frequency band. The necessity of implementing this type of magnetometer is presented in order to monitor high frequency magnetic signals from the electronics on-board. We show that the LPF coils have a performance one order of magnitude better than the current requirements set by the LISA mission at the low end of the audio-band frequency. The LPF coils are able to measure a magnetic noise level of 1.45 at 50 Hz and 0.17 at 500 Hz. Additionally, the LPF coils can reach a magnetic noise floor of 0.1 at frequencies above 1 kHz.
{"title":"Antenna for the detection of electromagnetic audio-band disturbances on-board LISA","authors":"D Serrano, A Pérez-Ortega, D Roma-Dollase, J Salvans-Tort, J J Ho-Zhang, J Ramos-Castro and M Nofrarias","doi":"10.1088/1361-6382/ae1c8c","DOIUrl":"https://doi.org/10.1088/1361-6382/ae1c8c","url":null,"abstract":"The LISA mission will be the first observatory to detect gravitational waves from space within the millihertz frequency band. Magnetic forces have an important impact on the instrument’s sensitivity below the millihertz. Hence, monitoring the magnetic environment within each of the LISA spacecrafts is of utmost importance. In this Letter we present the characterization of the coils that were used in LISA Pathfinder (LPF) when operating as magnetic sensors in the audio frequency band. The necessity of implementing this type of magnetometer is presented in order to monitor high frequency magnetic signals from the electronics on-board. We show that the LPF coils have a performance one order of magnitude better than the current requirements set by the LISA mission at the low end of the audio-band frequency. The LPF coils are able to measure a magnetic noise level of 1.45 at 50 Hz and 0.17 at 500 Hz. Additionally, the LPF coils can reach a magnetic noise floor of 0.1 at frequencies above 1 kHz.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"31 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145728707","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：