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}
Pub Date : 2025-12-12DOI: 10.1088/1361-6382/ae2417
Piotr T Chruściel and Raphaela Wutte
We review notions of mass of asymptotically locally Anti-de Sitter three-dimensional spacetimes, and apply them to some known solutions. For two-dimensional general relativistic initial data sets the mass is not invariant under asymptotic symmetries, but a unique mass parameter can be obtained either by minimisation, or by a monodromy construction, or both. We give an elementary proof of positivity, and of a Penrose-type inequality, in a natural gauge. We carry-out a gluing construction at infinity to time-symmetric asymptotically locally hyperbolic vacuum initial data sets and derive mass/entropy formulae for the resulting manifolds. Finally, we show that all mass aspect functions can be realised by constant scalar curvature metrics on complete manifolds which are smooth except for at most one conical singularity.
{"title":"Gluing-at-infinity of two-dimensional asymptotically locally hyperbolic manifolds *","authors":"Piotr T Chruściel and Raphaela Wutte","doi":"10.1088/1361-6382/ae2417","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2417","url":null,"abstract":"We review notions of mass of asymptotically locally Anti-de Sitter three-dimensional spacetimes, and apply them to some known solutions. For two-dimensional general relativistic initial data sets the mass is not invariant under asymptotic symmetries, but a unique mass parameter can be obtained either by minimisation, or by a monodromy construction, or both. We give an elementary proof of positivity, and of a Penrose-type inequality, in a natural gauge. We carry-out a gluing construction at infinity to time-symmetric asymptotically locally hyperbolic vacuum initial data sets and derive mass/entropy formulae for the resulting manifolds. Finally, we show that all mass aspect functions can be realised by constant scalar curvature metrics on complete manifolds which are smooth except for at most one conical singularity.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"148 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145728710","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 : 2025-12-11DOI: 10.1088/1361-6382/ae255e
Carlos Palenzuela, Miguel Bezares, Steven Liebling, Federico Schianchi, Julio Fernando Abalos, Ricard Aguilera-Miret, Carles Bona, Juan Antonio Carretero, Joan Massó, Matthew P Smith, Kwabena Amponsah, Kacper Kornet, Borja Miñano, Shrey Pareek and Miren Radia
We present MHDuet, an open source evolution code for general relativistic magnetohydrodynamics with neutrino transport. The code solves the full set of Einstein equations coupled to a relativistic, magnetized fluid with an M1 neutrino radiation scheme using advanced techniques, including adaptive mesh and large eddy simulation techniques, to achieve high accuracy. The Simflowny platform generates the code from a high-level specification of the computational system, producing code that runs with either the structured adaptive mesh refinement application infrastructure (SAMRAI) or adaptive mesh refinement framework for exascale computing (AMReX) infrastructure. The choice of AMReX enables compilation and execution on graphical processing units, running an order of magnitude faster than on central processing units at the node level. We validate the code against benchmark tests, reproducing previous results obtained with the SAMRAI infrastructure, and demonstrate its capabilities with simulations of neutron stars employing realistic tabulated equations of state. Resolution studies clearly demonstrate convergence faster than second order in the grid spacing. Scaling tests reveal excellent strong and weak scaling performance when running on graphical processing units. The goal of the code is to provide a powerful tool for studying the dynamics of compact objects within multi-messenger astrophysics.
{"title":"MHDuet: a high-order general relativistic radiation MHD code for CPU and GPU architectures","authors":"Carlos Palenzuela, Miguel Bezares, Steven Liebling, Federico Schianchi, Julio Fernando Abalos, Ricard Aguilera-Miret, Carles Bona, Juan Antonio Carretero, Joan Massó, Matthew P Smith, Kwabena Amponsah, Kacper Kornet, Borja Miñano, Shrey Pareek and Miren Radia","doi":"10.1088/1361-6382/ae255e","DOIUrl":"https://doi.org/10.1088/1361-6382/ae255e","url":null,"abstract":"We present MHDuet, an open source evolution code for general relativistic magnetohydrodynamics with neutrino transport. The code solves the full set of Einstein equations coupled to a relativistic, magnetized fluid with an M1 neutrino radiation scheme using advanced techniques, including adaptive mesh and large eddy simulation techniques, to achieve high accuracy. The Simflowny platform generates the code from a high-level specification of the computational system, producing code that runs with either the structured adaptive mesh refinement application infrastructure (SAMRAI) or adaptive mesh refinement framework for exascale computing (AMReX) infrastructure. The choice of AMReX enables compilation and execution on graphical processing units, running an order of magnitude faster than on central processing units at the node level. We validate the code against benchmark tests, reproducing previous results obtained with the SAMRAI infrastructure, and demonstrate its capabilities with simulations of neutron stars employing realistic tabulated equations of state. Resolution studies clearly demonstrate convergence faster than second order in the grid spacing. Scaling tests reveal excellent strong and weak scaling performance when running on graphical processing units. The goal of the code is to provide a powerful tool for studying the dynamics of compact objects within multi-messenger astrophysics.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"105 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145717562","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 : 2025-12-11DOI: 10.1088/1361-6382/ae2560
Noah M MacKay
The final pulse of gravitational wave (GW) emission is released at the peak of the chirp rise before compact binary merger. LIGO detections since GW150914 reveal a correlation between the radiated energy and the ad hoc scaling of one-tenth of the chirp mass , which begs to ask if this is physically grounded. Motivated by current effective one-body models, this work models compact binary coalescence as a rotating, compact mass shell that is contracting towards the total mass horizon. Using a variational methodology, the Laplace–Beltrami formulation for the Ricci tensor is applied to a Kerr metric Ansatz, retrieving the energy density T00 of the compact binary (CB) mass shell via the Einstein field equations. At the time of coalescence , the corresponding surface energy ultimately depends on the reduced mass µ of the CB, the symmetric mass ratio α, and the CB’s normalized orbital spin velocity. In other words, this surface energy is the anticipated energy radiated as GWs, which is not one-tenth of the chirp mass systematically. Under simple assumptions, the anticipated energy for GW150914 – a representative example—is using documented center values. Under a more rigorous analysis in comparison, the anticipated energy for GW150914 is . This is compared with the GWTC recorded value of for GW150914, with the latter analysis providing a closer approximation to the actual value. This study also includes the derivation of GW forms from the CB mass shell model, which depend on dynamic frequencies and decreasing CB separations.
{"title":"A mass-shell model of compact binary coalescence","authors":"Noah M MacKay","doi":"10.1088/1361-6382/ae2560","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2560","url":null,"abstract":"The final pulse of gravitational wave (GW) emission is released at the peak of the chirp rise before compact binary merger. LIGO detections since GW150914 reveal a correlation between the radiated energy and the ad hoc scaling of one-tenth of the chirp mass , which begs to ask if this is physically grounded. Motivated by current effective one-body models, this work models compact binary coalescence as a rotating, compact mass shell that is contracting towards the total mass horizon. Using a variational methodology, the Laplace–Beltrami formulation for the Ricci tensor is applied to a Kerr metric Ansatz, retrieving the energy density T00 of the compact binary (CB) mass shell via the Einstein field equations. At the time of coalescence , the corresponding surface energy ultimately depends on the reduced mass µ of the CB, the symmetric mass ratio α, and the CB’s normalized orbital spin velocity. In other words, this surface energy is the anticipated energy radiated as GWs, which is not one-tenth of the chirp mass systematically. Under simple assumptions, the anticipated energy for GW150914 – a representative example—is using documented center values. Under a more rigorous analysis in comparison, the anticipated energy for GW150914 is . This is compared with the GWTC recorded value of for GW150914, with the latter analysis providing a closer approximation to the actual value. This study also includes the derivation of GW forms from the CB mass shell model, which depend on dynamic frequencies and decreasing CB separations.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"57 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145717524","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 : 2025-12-11DOI: 10.1088/1361-6382/ae255f
Min-Seok Seo
String compactification in the framework of the low energy effective supergravity requires the perturbative control in both the large volume and the weak coupling expansions. However, when the complex structure moduli couple to some lattice structure, the Sp symmetry of the tree level Kähler potential allows the correction to the Kähler potential to diverge in the large field limit of the complex structure moduli, resulting in the breakdown of the perturbative control. Here the lattice structure naturally appears in the presence of a tower of states like the Kaluza–Klein (KK) or the string modes, an essential ingredient of the distance conjecture. The similar situation can be found from the axio-dilaton contribution to the corrected Kähler potential, where the SL symmetry as well as the coupling between the axio-dilaton and the lattice structure allow the correction to diverge in the weak coupling limit. In order to keep the perturbative control, the values of the complex structure moduli as well as the dilaton must have the upper bound, which is determined by the volume of the internal manifold and the string coupling constant, hence the KK and the string mass scales. The form of the bounds are quite similar to that given by the distance conjecture, both prevents the descent of a tower of states.
{"title":"Bounds on complex structure moduli values for perturbative control","authors":"Min-Seok Seo","doi":"10.1088/1361-6382/ae255f","DOIUrl":"https://doi.org/10.1088/1361-6382/ae255f","url":null,"abstract":"String compactification in the framework of the low energy effective supergravity requires the perturbative control in both the large volume and the weak coupling expansions. However, when the complex structure moduli couple to some lattice structure, the Sp symmetry of the tree level Kähler potential allows the correction to the Kähler potential to diverge in the large field limit of the complex structure moduli, resulting in the breakdown of the perturbative control. Here the lattice structure naturally appears in the presence of a tower of states like the Kaluza–Klein (KK) or the string modes, an essential ingredient of the distance conjecture. The similar situation can be found from the axio-dilaton contribution to the corrected Kähler potential, where the SL symmetry as well as the coupling between the axio-dilaton and the lattice structure allow the correction to diverge in the weak coupling limit. In order to keep the perturbative control, the values of the complex structure moduli as well as the dilaton must have the upper bound, which is determined by the volume of the internal manifold and the string coupling constant, hence the KK and the string mass scales. The form of the bounds are quite similar to that given by the distance conjecture, both prevents the descent of a tower of states.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"145 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145717563","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 : 2025-12-10DOI: 10.1088/1361-6382/ae2415
Chad Henshaw, Jacob Lange, Peter Lott, Richard O’Shaughnessy and Laura Cadonati
Systems of two black holes with unbound orbits can produce a diverse array of gravitational wave signals with rich morphology. This parameter space encompasses both hyperbolic orbit scattering events and dynamical captures, including zoom-whirl orbits with multiple flybys and direct plunge mergers. These signals challenge traditional parameter estimation infrastructure, which is largely optimized for quasicircular inspiral binaries. In this work we discuss the adaptation of the Rapid Iterative FiTting (RIFT) algorithm to this problem using the TEOBResumSDALI waveform model which can simulate generic orbits. We present results from a study of simulated signals emulating a scatter and plunge event, utilizing the design sensitivity of the forthcoming Cosmic Explorer interferometer. Our analysis demonstrates that RIFT accurately recovers the mass, spins, and hyperbolic orbit parameters: the system energy and angular momentum defined at a fiducial initial separation.
{"title":"Parameter estimation of gravitational waves from hyperbolic black hole encounters","authors":"Chad Henshaw, Jacob Lange, Peter Lott, Richard O’Shaughnessy and Laura Cadonati","doi":"10.1088/1361-6382/ae2415","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2415","url":null,"abstract":"Systems of two black holes with unbound orbits can produce a diverse array of gravitational wave signals with rich morphology. This parameter space encompasses both hyperbolic orbit scattering events and dynamical captures, including zoom-whirl orbits with multiple flybys and direct plunge mergers. These signals challenge traditional parameter estimation infrastructure, which is largely optimized for quasicircular inspiral binaries. In this work we discuss the adaptation of the Rapid Iterative FiTting (RIFT) algorithm to this problem using the TEOBResumSDALI waveform model which can simulate generic orbits. We present results from a study of simulated signals emulating a scatter and plunge event, utilizing the design sensitivity of the forthcoming Cosmic Explorer interferometer. Our analysis demonstrates that RIFT accurately recovers the mass, spins, and hyperbolic orbit parameters: the system energy and angular momentum defined at a fiducial initial separation.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"110 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711408","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 : 2025-12-10DOI: 10.1088/1361-6382/ae2416
Carlos Silva
In this paper, we propose a relationship between the so-called Hubble–Lemaî tre constant H0 and the holographic complexity related to the emergence of spacetime in quantum gravity. Such a result can represent an important step to understanding the Hubble tension by introducing a quantum gravity perspective for cosmological observations, regarding the degree of quantum complexity we measure around us.
{"title":"Holographic complexity and the Hubble tension: a quantum gravity portrayal for the large scale structure of the cosmos","authors":"Carlos Silva","doi":"10.1088/1361-6382/ae2416","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2416","url":null,"abstract":"In this paper, we propose a relationship between the so-called Hubble–Lemaî tre constant H0 and the holographic complexity related to the emergence of spacetime in quantum gravity. Such a result can represent an important step to understanding the Hubble tension by introducing a quantum gravity perspective for cosmological observations, regarding the degree of quantum complexity we measure around us.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"34 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711410","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 : 2025-12-10DOI: 10.1088/1361-6382/ae255d
Dilip Kumar
In this study, we explore the combined effects of quantum gravity induced by non-commutativity and scale-dependent gravitational coupling on the thermal properties of the thin accretion disks around a Schwarzschild black hole. We consider a κ-deformed renormalization group induced (RGI) Schwarzschild black hole, where the classical Schwarzschild black hole geometry is modified by the κ-deformation of space-time and the running Newton’s coupling constant G(r). Using the modified metric, we derive the geodesic motion of massive particles, the effective potential, and the thermal properties such as the radiated energy flux, luminosity, and the temperature profile of the accretion disk around the κ-deformed RGI-Schwarzschild black hole. Our study shows that when non-commutativity is combined with the RGI framework, the effects produce a noticeable deviation from the classical Schwarzschild case. In particular, for small values of the deformation parameter, we observe an increase in the peak energy flux and the temperature of the accretion disk. This suggests that quantum gravity corrections enhance the disk’s radiative efficiency, especially in the inner regions closer to the black hole.
{"title":"Effect of noncommutative geometry on accretion disks around RGI-Schwarzschild black hole","authors":"Dilip Kumar","doi":"10.1088/1361-6382/ae255d","DOIUrl":"https://doi.org/10.1088/1361-6382/ae255d","url":null,"abstract":"In this study, we explore the combined effects of quantum gravity induced by non-commutativity and scale-dependent gravitational coupling on the thermal properties of the thin accretion disks around a Schwarzschild black hole. We consider a κ-deformed renormalization group induced (RGI) Schwarzschild black hole, where the classical Schwarzschild black hole geometry is modified by the κ-deformation of space-time and the running Newton’s coupling constant G(r). Using the modified metric, we derive the geodesic motion of massive particles, the effective potential, and the thermal properties such as the radiated energy flux, luminosity, and the temperature profile of the accretion disk around the κ-deformed RGI-Schwarzschild black hole. Our study shows that when non-commutativity is combined with the RGI framework, the effects produce a noticeable deviation from the classical Schwarzschild case. In particular, for small values of the deformation parameter, we observe an increase in the peak energy flux and the temperature of the accretion disk. This suggests that quantum gravity corrections enhance the disk’s radiative efficiency, especially in the inner regions closer to the black hole.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"20 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711414","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 : 2025-12-08DOI: 10.1088/1361-6382/ae2414
Shuanglin Huang, Xuefeng Feng and Yun-Kau Lau
Motivated by a geometric understanding of the angular velocity of a Kerr black hole in terms of a quasi-conformal map that describes a 2d Beltrami fluid flow, a new way to construct initial data sets for binary rotating black holes by prescribing the angular velocities of the two black holes at their horizons is discussed. A set of elliptic equations with prescribed Dirichlet boundary conditions at the horizons and at spatial infinity is established for constructing the initial data. To explore the dynamics encoded in these initial data, we consider the conformally flat three-metric case and numerically evolve it using the BSSN code for two co-rotating and counter-rotating black holes with angular velocities prescribed at the horizons. When the angular velocities are non-uniform and deviate from a constant value at the horizons, new gravitational waveforms are generated which display certain oscillatory pattern reminiscent of that of quasi-normal ringing in the inspiral phase before merger takes place.
{"title":"Angular velocity of rotating black holes—a new way to construct initial data for binary black holes","authors":"Shuanglin Huang, Xuefeng Feng and Yun-Kau Lau","doi":"10.1088/1361-6382/ae2414","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2414","url":null,"abstract":"Motivated by a geometric understanding of the angular velocity of a Kerr black hole in terms of a quasi-conformal map that describes a 2d Beltrami fluid flow, a new way to construct initial data sets for binary rotating black holes by prescribing the angular velocities of the two black holes at their horizons is discussed. A set of elliptic equations with prescribed Dirichlet boundary conditions at the horizons and at spatial infinity is established for constructing the initial data. To explore the dynamics encoded in these initial data, we consider the conformally flat three-metric case and numerically evolve it using the BSSN code for two co-rotating and counter-rotating black holes with angular velocities prescribed at the horizons. When the angular velocities are non-uniform and deviate from a constant value at the horizons, new gravitational waveforms are generated which display certain oscillatory pattern reminiscent of that of quasi-normal ringing in the inspiral phase before merger takes place.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"138 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145697364","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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