Classical and Quantum Gravity最新文献_第6页

Particle creation, clock variables, and relabelling symmetry in pull-back variational fluids 回拉变分流体中的粒子创建、时钟变量和重新标记对称性

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2026-09-08 DOI: 10.1088/1361-6382/aea468

Hyeong-Chan Kim

{"title":"Particle creation, clock variables, and relabelling symmetry in pull-back variational fluids","authors":"Hyeong-Chan Kim","doi":"10.1088/1361-6382/aea468","DOIUrl":"https://doi.org/10.1088/1361-6382/aea468","url":null,"abstract":"Abstract Particle-number conservation is an off-shell kinematical identity of the standard pull-back variational formulation when the matter-space three-form depends only on the comoving labels of a constituent. We revisit the relabelling argument when the matter-space density also carries particle-creation information. The conservative contribution to the Eulerian current variation then cannot be considered alone: the variation of the creation sector must be included. For the three constructions studied here---a proper-time functional, an independent local scalar clock, and interacting matter spaces---the full current variation is invariant under flow-aligned relabellings even when $Gamma_Nequivnabla_a n^aneq0$. The constructions differ instead in locality, field content, and dynamical closure. A proper-time clock introduces no additional field, but its variation contains an acceleration-dependent history term and its metric dependence produces a non-local longitudinal stress contribution. An independent scalar clock is local but requires its own dynamics or constraint; a freely varied algebraic clock forces $Gamma_N=0$. Interacting matter spaces provide a local description of inter-species conversion through the relative dynamics of the partner fluids. On FLRW backgrounds the two single-fluid realizations can reproduce the same homogeneous creation history, but the background law does not determine its perturbative completion. The gauge-invariant mismatch $Delta_Gamma=deltaGamma-betadeltatheta$ controls the non-adiabatic creation pressure in the effective one-fluid description, and its value depends jointly on the clock dynamics and the constitutive completion of the creation law. Thus particle creation is compatible with pull-back relabelling symmetry, provided the additional creation-sector structure needed for closure is specified.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"37 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148923312","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

Ultraviolet Closure in Asymptotically Weyl-Invariant Gravity 渐近weyl不变引力中的紫外闭包

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2026-09-08 DOI: 10.1088/1361-6382/aea465

Daniel Coumbe

{"title":"Ultraviolet Closure in Asymptotically Weyl-Invariant Gravity","authors":"Daniel Coumbe","doi":"10.1088/1361-6382/aea465","DOIUrl":"https://doi.org/10.1088/1361-6382/aea465","url":null,"abstract":"Abstract We investigate asymptotically Weyl-invariant gravity (AWIG) in the Palatini formulation, defined by an exponent that interpolates between an Einstein-like infrared regime, where (nto1), and a Weyl-invariant ultraviolet regime, where (nto2). In four dimensions, we show that exact Weyl invariance within the minimal scalar Palatini (f(mathcal{R})) sector uniquely selects the (mathcal{R}^2) action as the ultraviolet endpoint. Interpreting the exponent as an effective curvature-dependent quantity, we constrain a phenomenological class of smooth autonomous flows compatible with the required infrared and ultraviolet endpoints. We then analyse the strict ultraviolet theory. On the regular branch (mathcal{R}neq0), and within a restricted torsionless, parity-even sector constructed purely from curvature, all admissible divergent on-shell counterterms reduce at arbitrary loop order to the original (sqrt{-g},mathcal{R}^2) term plus a topological Euler density. Although this conditional result does not establish full off-shell perturbative renormalizability, it provides nontrivial evidence for improved ultraviolet behaviour relative to Einstein gravity and identifies a concrete target for a future first-principles renormalization-group calculation.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"19 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148923314","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

Gravitational and kinematic redshifts of black holes in nonlinear electrodynamics 非线性电动力学中黑洞的引力和运动学红移

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2026-09-08 DOI: 10.1088/1361-6382/aea467

Marco Aurélio Abreu de Paula,Mustapha Azreg-Aïnou

{"title":"Gravitational and kinematic redshifts of black holes in nonlinear electrodynamics","authors":"Marco Aurélio Abreu de Paula,Mustapha Azreg-Aïnou","doi":"10.1088/1361-6382/aea467","DOIUrl":"https://doi.org/10.1088/1361-6382/aea467","url":null,"abstract":"Abstract Spacetimes arising from nonlinear electrodynamics (NED) are a good laboratory for studying both the nature of regular black hole (RBH) solutions and the imprints of nonlinear electromagnetic fields within this context. Over the past few decades, NED-sourced black hole (BH) spacetimes have attracted considerable attention, but electrically charged RBHs obtained in the so-called $F$ framework have been less addressed in the literature. We consider two electrically charged, fully regular members of the h-family that are solutions to general relativity minimally coupled to NED. Because of their potential astrophysical and astronomical applications, we mainly focus our investigation on the motion of photons and its implications for the gravitational and kinematic redshifts, as well as for the shadow radius, considering the effective geometry followed by photons in NED. Moreover, we consider the observational data for Sagittarius A$^{star}$ and Messier 87$^{star}$ BHs to impose some constraints on the charge-to-mass ratio of the fully RBHs. We obtain the general equations that govern the gravitational and kinematic redshifts of NED-sourced BH spacetimes. In particular, for fully RBHs with BH charge-to-mass ratios above some moderate value, we observe discrepancies in their physical and geometrical properties compared to those of the Reissner--Nordstr\"om (RN) BH. Therefore, our results indicate that it is possible to distinguish NED-based RBH solutions from RN BHs, from the perspective of gravitational and kinematic redshifts, suggesting potential astrophysical relevance.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"69 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148923313","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

Photon-sphere bifurcations and naked photon sphere phases in pseudo-complex general relativity 伪复广义相对论中的光子球分岔和裸光子球相

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2026-09-08 DOI: 10.1088/1361-6382/aea466

Leila Maghlaoui,Peter O Hess,Cesar Augusto Zen Vasconcellos,Fridolin Weber

{"title":"Photon-sphere bifurcations and naked photon sphere phases in pseudo-complex general relativity","authors":"Leila Maghlaoui,Peter O Hess,Cesar Augusto Zen Vasconcellos,Fridolin Weber","doi":"10.1088/1361-6382/aea466","DOIUrl":"https://doi.org/10.1088/1361-6382/aea466","url":null,"abstract":"Abstract In Pseudo-Complex General Relativity (pcGR), the introduction of a&#xD;repulsive core modifies the strong-field geometry of compact objects and&#xD;alters the structure of null geodesics. In this work, we reformulate the&#xD;exact radial motion of photons as an autonomous dynamical system and use&#xD;phase-space methods to classify the resulting geometric regimes. We show&#xD;that the existence of circular null orbits is controlled by a saddle-node&#xD;bifurcation occurring at the critical coupling&#xD;$B_4^{(mathrm{ps})}= (2187/128)M^4$.&#xD;Below this threshold, the spacetime supports an unstable photon sphere,&#xD;while above it all real circular null geodesics are eliminated from the&#xD;phase space.&#xD;&#xD;We further identify a finite intermediate regime, $10.125 < B_4/M^4 <&#xD;17.086$, in which the event horizon is absent but the photon sphere&#xD;persists. This Naked Photon Sphere phase demonstrates that the loss of&#xD;the horizon and the loss of circular null geodesics are distinct&#xD;geometric transitions in pcGR.&#xD;&#xD;Finally, we examine the semiclassical thermodynamic evolution of the&#xD;system. Within the standard continuation of the horizon branch, the&#xD;evaporation trajectory approaches a stable remnant configuration whose&#xD;mass satisfies $M_{rm rem}>M_{rm crit}$, where $M_{rm crit}$&#xD;denotes the mass associated with the photon-sphere&#xD;bifurcation.&#xD;Consequently, within this semiclassical framework, the remnant endpoint&#xD;lies above the photon-sphere bifurcation scale, so the physical trajectory&#xD;does not reach the regime in which circular null orbits are eliminated.&#xD;These results establish a direct link between phase-space dynamics,&#xD;compact-object geometry, and remnant formation in pcGR.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"77 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148923311","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

Linear Gravitational Wave Memory Through the Window of Core-Collapse Supernova 通过核心坍缩超新星窗口的线性引力波记忆

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2026-09-07 DOI: 10.1088/1361-6382/aea396

Colter J. Richardson,Anthony Mezzacappa,Haakon Andresen,Michele Zanolin

引用次数: 0

Primordial thermal gravitational waves from warm inflation 来自热暴胀的原始热引力波

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2026-09-07 DOI: 10.1088/1361-6382/aea394

Anupama B

引用次数: 0

From Localization to Discovery: Bayesian Ranking of Electromagnetic Counterparts to Gravitational-Wave Events 从定位到发现：引力波事件电磁对应物的贝叶斯排序

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2026-09-07 DOI: 10.1088/1361-6382/aea397

Kendall Ackley

{"title":"From Localization to Discovery: Bayesian Ranking of Electromagnetic Counterparts to Gravitational-Wave Events","authors":"Kendall Ackley","doi":"10.1088/1361-6382/aea397","DOIUrl":"https://doi.org/10.1088/1361-6382/aea397","url":null,"abstract":"Abstract The robust association of electromagnetic candidates discovered during follow-up of gravitational-wave alerts is challenging, not only due to the large sky areas and broad distance uncertainties, but also due to the tens to hundreds of unrelated optical transients that are observed per event. &#xD;We present a Bayesian ranking framework to identify candidate electromagnetic counterparts to gravitational-wave events without requiring photometric or spectroscopic classification. The method ranks transient candidates according to their consistency with the three-dimensional gravitational-wave localization and quantifies the significance of their associations. The framework combines morphology-aware host association, physically motivated offset priors, host-inferred luminosity distance posteriors, peculiar velocity corrections, and a treatment for missing or incorrectly associated host galaxies.&#xD;We apply the method to two events, GW170817 and GW190425. For GW170817, the method ranks AT2017gfo first and correctly recovers NGC,4993 as the host galaxy. We find a candidate p-value of 0.030 for AT2017gfo and find none of the 32 background transient sources reach the ranking value of AT2017gfo. For GW190425, the highest-ranked candidate has a p-value of $5.88times 10^{-4}$ relative to 5101 background sources. Correcting for the multiple comparisons problem using the full set of 433 candidates lowers the significance of the top-ranked candidate to a p-value of 0.255.&#xD;The framework is directly applicable to transient candidates with only sky location information, enables rapid prioritization for more efficient follow-up, and leads to more reliable counterpart identification in current and future observing runs.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"54 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148923357","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

Phase-Induced Particle Creation in the Kappa-Gamma Vacuum Kappa-Gamma真空中相诱导粒子的产生

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2026-09-07 DOI: 10.1088/1361-6382/aea395

Arash Azizi

{"title":"Phase-Induced Particle Creation in the Kappa-Gamma Vacuum","authors":"Arash Azizi","doi":"10.1088/1361-6382/aea395","DOIUrl":"https://doi.org/10.1088/1361-6382/aea395","url":null,"abstract":"Abstract The $kappa$ plane wave construction describes a one-parameter family of vacua as continuous-mode squeezed states of the Minkowski vacuum, with a real, frequency-dependent squeezing magnitude set by a single scale $kappa$. Here we promote this real squeezing to complex squeezing by introducing a phase angle $gamma$, obtaining a two-parameter family of $kappagamma$ plane wave modes and vacua $|0_{kappagamma}rangle$ in which $kappa$ fixes the squeezing magnitude and $gamma$ fixes its orientation in phase space. Our central result is phase-induced particle creation: at fixed $kappa$, a mismatch $Deltagamma$ between the phase that prepares the state and the phase that defines particles yields a nonzero Bogoliubov population, which vanishes when the two phases coincide and is enhanced in the infrared. This is an algebraic separation of squeezed-state particle notions that becomes a genuine dynamical creation process when a physical control---such as a modulated accelerating mirror---rotates $gamma$ in time. We derive the reciprocal Bogoliubov maps between the $kappagamma$ plane wave and $kappa_{rm R}$-Rindler bases, and evaluate the Wightman function, which splits into a stationary thermal (KMS) part set by $kappa$ and a phase-sensitive nonstationary part set by $gamma$. The latter also contributes to point-split local observables, producing a generally $gamma$-dependent nonstationary flux despite unchanged diagonal Planckian weights. With the stated infrared prescription the $kappagamma$ vacuum is Hadamard, carrying the standard Minkowski short-distance singularity and no additional horizon singularity.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"56 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148923353","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

Quantification of the parameter estimation error from rotating core collapse supernovae 旋转核心坍缩超新星参数估计误差的量化

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2026-09-04 DOI: 10.1088/1361-6382/ae9c7f

Claudia Moreno,Javier M Antelis,Michele Zanolin

{"title":"Quantification of the parameter estimation error from rotating core collapse supernovae","authors":"Claudia Moreno,Javier M Antelis,Michele Zanolin","doi":"10.1088/1361-6382/ae9c7f","DOIUrl":"https://doi.org/10.1088/1361-6382/ae9c7f","url":null,"abstract":"Abstract In this paper, we perform parameter estimation with an analytical model to simulate the gravitational wave emission during the core-bounce phase of a rapidly rotating core collapse supernova progenitor. This approach enables us to estimate the parameter β , defined as the ratio of rotational kinetic energy to gravitational potential energy in core-collapse supernovae. To verify the reliability of both the analytical model and the inferred value of β , we use a numerical template bank constructed from Abylkairov’s gravitational waveform catalog and simulate O4 noise, characterized by the interferometer’s power spectral density. An average fitting factor of 94% over the interval 0.02 < β < 0.14 shows that our analytical model reproduces the key characteristics of the core-bounce waveform with high accuracy, leading to only a 6% reduction in the optimal signal-to-noise ratio. This provides a quantitative measure of how well the analytical model performs. Subsequently, we analyze the error in estimating β using a Matched Filter method and compare it to the corresponding Cramér–Rao Lower Bound. The results obtained by considering noise and waveforms at distances of 5, 10, and 50 kpc enable an assessment of how accurately the selected statistical model fits the observed data. From the asymptotic expansion of the variance, we derive a theoretical lower bound for the error that falls below 10 − 1 when the parameter β decreases with distance.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"35 1","pages":"175015"},"PeriodicalIF":3.5,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148894167","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

A quantum circuit model of black hole evaporation with tunable semi-causality violation 具有可调谐半因果违背的黑洞蒸发量子电路模型

IF 3.5 3区物理与天体物理

Classical and Quantum Gravity Pub Date : 2026-09-04 DOI: 10.1088/1361-6382/ae9de6

Sourav Ballav,Wen-Yu Wen,Chi-Hsien Tai

{"title":"A quantum circuit model of black hole evaporation with tunable semi-causality violation","authors":"Sourav Ballav,Wen-Yu Wen,Chi-Hsien Tai","doi":"10.1088/1361-6382/ae9de6","DOIUrl":"https://doi.org/10.1088/1361-6382/ae9de6","url":null,"abstract":"Abstract We present a four-qubit quantum circuit model of black-hole evaporation with a controlled violation of semi-causality, understood as the condition that information may fall into the black hole but cannot propagate back across the horizon. Building on Broda’s semi-causal evaporation circuit, we introduce a controlled-unitary gate CU ( σ ) that allows tunable information leakage from the interior to the exterior while preserving global unitarity. We compute the single-qubit reduced entropies, together with the mutual information and entanglement negativity for the BH-GR and IN–OUT bipartitions, at each discrete time step. For σ = 0 , the model reproduces Broda’s Page-like entropy evolution with complete late-time purification. For any σ > 0 , however, nonzero residual single-qubit entropies and persistent late-time entanglement remain, indicating incomplete purification of the outgoing radiation despite the global unitary evolution. In the small- σ regime, the residual entropy exhibits a characteristic − σ 2 ln ⁡ σ 2 scaling that bears qualitative similarity to logarithmic entropy corrections in generalized-uncertainty-principle inspired evaporation scenarios. For larger values of σ , the persistence of finite residual entropy invites comparison with remnant-like endpoint configurations in regular or extremal black-hole models. Our results show how controlled departures from the semi-causal limit modify information recovery in a minimal analytically tractable model of black-hole evaporation.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"8 1","pages":"175011"},"PeriodicalIF":3.5,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148894169","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