General Relativity and Gravitation最新文献

Some examples of use of transfinite induction in analysis 超限归纳法在分析中的应用

IF 2.8 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2026-05-07 DOI: 10.1007/s10714-026-03553-y

Nicola Gigli

{"title":"Some examples of use of transfinite induction in analysis","authors":"Nicola Gigli","doi":"10.1007/s10714-026-03553-y","DOIUrl":"10.1007/s10714-026-03553-y","url":null,"abstract":"<div><p>It is not uncommon in analysis that existence of extremal objects is obtained via an iterative procedure: we start from a given admissible object, then modify it, then modify again etc... If being extremal means maximimizing a real valued quantity and we are sure to approach the supremum fast enough, after a countable number of steps and a limiting procedure we are done. In this short note we want to advertise a slightly different line of thought, where rather than trying to approach the supremum fast enough, we: try to increase, if possible, the function to be maximized and, at the same time, index our recursive procedure over ordinals. Since there are no increasing functions from <span>(omega _1)</span> to <span>(mathbb {R})</span>, the procedure must stop at some countable ordinal and existence is proved anyway. The advantage of this line of reasoning is that it can be helpful even in situations where it is not so evident how to measure ‘being maximal’ via a real valued function. This is the case, for instance, for existence of a Maximal Globally Hyperbolic Development of an initial data set in General Relativity. Speaking of this particular example, we also show that such ‘real-valued quantification’ of the size of a development is actually possible, thus existence of a maximal one can be obtained in a countable number of steps using the original argument in [3] together with the standard procedure depicted above. This provides a way alternative to the one given in [9] to ‘dezornify’ the proof in [3].\u0000</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"58 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

The (C^0)-inextendibility of some spatially flat FLRW spacetimes 某些空间平坦FLRW时空的(C^0) -不可扩展性

IF 2.8 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2026-05-04 DOI: 10.1007/s10714-026-03555-w

Eric Ling

引用次数: 0

Metric-affine black holes under quantum gravity corrections: tunnelling Dirac particles and gravitational lensing analysis 量子引力修正下的度量仿射黑洞：隧穿狄拉克粒子和引力透镜分析

IF 2.8 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2026-05-03 DOI: 10.1007/s10714-026-03557-8

Erdem Sucu

{"title":"Metric-affine black holes under quantum gravity corrections: tunnelling Dirac particles and gravitational lensing analysis","authors":"Erdem Sucu","doi":"10.1007/s10714-026-03557-8","DOIUrl":"10.1007/s10714-026-03557-8","url":null,"abstract":"<div><p>In this work, we study the physical characteristics of black holes within the Metric–Affine Gravity framework, where both torsion and nonmetricity are independent parts of spacetime geometry. Starting from the field equations, a spherically symmetric solution is obtained that includes contributions from spin, dilation, and shear parameters. The thermal properties of the black hole are studied using the tunnelling approach for Dirac particles, which allows the calculation of the Hawking temperature and shows how torsion and nonmetricity influence it. Quantum effects are then added through the Generalized Uncertainty Principle and an exponential correction to the entropy to examine whether small black holes can remain stable and form remnants after evaporation. The weak deflection of light is also analyzed with the Gauss–Bonnet method to see how geometric charges change the bending of photons compared with the Schwarzschild case. The results indicate that the combined influence of torsion, nonmetricity, and quantum effects causes small but clear differences from classical General Relativity and provides a direct geometric way to study such deviations.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"58 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

On the space of cone geodesics and positive paths of contactomorphisms 圆锥测地线空间与接触形态的正路径

IF 2.8 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2026-04-29 DOI: 10.1007/s10714-026-03554-x

Jakob Hedicke

引用次数: 0

Charged relativistic fluids exchanging energy via gravitational decoupling in (f(T, tau )) gravity 带电相对论流体通过$$f(T, tau )$$重力解耦交换能量

IF 2.8 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2026-04-26 DOI: 10.1007/s10714-026-03552-z

Mohammad Alshammari, U. A. Khokhar, Javlon Rayimbaev, Munisbek Akhmedov, M. Z. Bhatti, Z. Yousaf

{"title":"Charged relativistic fluids exchanging energy via gravitational decoupling in (f(T, tau )) gravity","authors":"Mohammad Alshammari, U. A. Khokhar, Javlon Rayimbaev, Munisbek Akhmedov, M. Z. Bhatti, Z. Yousaf","doi":"10.1007/s10714-026-03552-z","DOIUrl":"10.1007/s10714-026-03552-z","url":null,"abstract":"<div><p>This paper analyzes the implications of modified gravity (<span>(f(T, tau ))</span> gravity, defined by the trace of the energy-momentum tensor as <span>(tau )</span> and the torsion scalar <i>T</i>) on a charged gravitational source in spherically symmetric as well as static space-times through the gravitational decoupling, irrespective of its characteristics. The qualitative characteristics of the system will be discussed using a linear functional form of the <span>(f(T, tau ))</span> model to conveniently examine the properties of the system. We evaluated how the electromagnetic field modifies the flow of energy in spherically symmetric and motionless celestial objects exhibiting relativistic fluid. The interior structure is built using a polytropic equation of state, and the corresponding matching with the exterior spacetime is performed by using suitable junction conditions. We point out that the current work does not pertain to the explicit nonlinear coupling on the Lagrangian level. Rather, the decoupling framework encoded the interaction between other matter sectors due to the effect of the gravitational field. Lastly, employing the Tolman <i>IV</i> solution, we detected energy conditions in the presence of charge by adopting <span>(f(T, tau ))</span> field equations and gathered the anticipated outcomes.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"58 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147751594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Melvin-Zipoy-Voorhees Spacetime and Circular Orbits Melvin-Zipoy-Voorhees时空和圆形轨道

IF 2.8 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2026-04-25 DOI: 10.1007/s10714-026-03551-0

Haryanto M. Siahaan

引用次数: 0

On the foundations and applications of Lorentz-Finsler Geometry 论洛伦兹-芬斯勒几何的基础及其应用

IF 2.8 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2026-04-24 DOI: 10.1007/s10714-026-03539-w

Miguel Sánchez

{"title":"On the foundations and applications of Lorentz-Finsler Geometry","authors":"Miguel Sánchez","doi":"10.1007/s10714-026-03539-w","DOIUrl":"10.1007/s10714-026-03539-w","url":null,"abstract":"<div><p>Finslerian extensions of Special and General Relativity—commonly referred to as Very Special and Very General Relativity— necessitate the development of a unified Lorentz-Finsler geometry. However, the scope of this geometric framework extends well beyond relativistic physics. Indeed, it offers powerful tools for modeling wave propagation in classical mechanics, discretizing spacetimes in classical and relativistic settings, and supporting effective theories in fundamental physics. Moreover, Lorentz-Finsler geometry provides a versatile setting that facilitates the resolution of problems within Riemannian, Lorentzian, and Finslerian geometries individually. This work presents a plain introduction to the subject, reviewing foundational concepts, key applications, and future prospects. The reviewed topics include (i) basics on the setting of cones, Finsler and Lorentz-Finsler metrics and their (nonlinear, anisotropic and linear) connections, (ii) the global structure of Lorentz-Finsler manifolds and its space of null geodesics, (iii) links among Riemannian, Finsler and Lorentz geometries, (iv) applications in classical settings as wildfires and seisms propagation, and discretization in classical and relativistic settings with quantum prospects, and (v) Finslerian variational approach to Einstein equations. The new results include the splitting of globally hyperbolic Finsler spacetimes, in addition to the analysis of several extensions of the Lorentz setting, as the case of timelike boundaries.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"58 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Dynamical systems analysis of an Einstein–Cartan ekpyrotic nonsingular bounce cosmology 爱因斯坦-卡坦非奇异弹跳宇宙论的动力系统分析

IF 2.8 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2026-04-22 DOI: 10.1007/s10714-026-03547-w

Jackson Stingley

{"title":"Dynamical systems analysis of an Einstein–Cartan ekpyrotic nonsingular bounce cosmology","authors":"Jackson Stingley","doi":"10.1007/s10714-026-03547-w","DOIUrl":"10.1007/s10714-026-03547-w","url":null,"abstract":"<div><p>I construct an Einstein–Cartan ekpyrotic model (ECEM): a homogeneous, nearly Friedmann–Lemaître–Robertson–Walker (FLRW) background in Einstein–Cartan (EC) gravity whose spin–torsion sector, modeled phenomenologically as a Weyssenhoff fluid with stiff scaling <span>(rho _spropto a^{-6})</span>, is coupled to a scalar field with a steep exponential potential that interpolates between a negative ekpyrotic branch and a positive plateau. Extending the Copeland–Liddle–Wands (CLW) scalar–fluid dynamical system to a six-dimensional phase space including shear, curvature, and spin–torsion, I recast the equations in a compact deceleration-parameter form, compute the full Jacobian, and evaluate maximal Lyapunov exponents. Numerical solutions show that the ekpyrotic branch (<span>(w_phi gg 1)</span>) exponentially damps homogeneous shear, while the softened branch (<span>(w_phi <1)</span>) allows <span>(rho _s)</span> to overtake the scalar during contraction and trigger a torsion-supported bounce at high but finite densities where the EC spin–torsion term becomes dynamically dominant. Scans in a two-parameter softening plane <span>((phi _textrm{b},Delta ))</span> identify a finite region of nonsingular trajectories and quantify the required tuning; in the parameter ranges explored the maximal Lyapunov exponent on the constrained phase space is negative, giving no indication of chaotic behavior in this homogeneous truncation even when the usual curvature mode that destabilizes contracting General Relativity (GR) backgrounds is included. The construction is purely phenomenological and confined to homogeneous backgrounds: it does not address entropy accumulation, the cosmological arrow of time, or a complete cyclic cosmology.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"58 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10714-026-03547-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147733408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermodynamics of rotating Lifshitz dilaton black branes in quartic quasitopological gravity 四次准拓扑重力中旋转lifshitz膨胀黑膜的热力学

IF 2.8 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2026-04-19 DOI: 10.1007/s10714-026-03541-2

M. Ghanaatian, F. Esmaeili, A. Bazrafshan, Gh. Forozani

{"title":"Thermodynamics of rotating Lifshitz dilaton black branes in quartic quasitopological gravity","authors":"M. Ghanaatian, F. Esmaeili, A. Bazrafshan, Gh. Forozani","doi":"10.1007/s10714-026-03541-2","DOIUrl":"10.1007/s10714-026-03541-2","url":null,"abstract":"<div><p>This paper investigates the thermodynamic properties of rotating Lifshitz black branes in quartic quasitopological gravity coupled to a dilaton field. We derive the field equations and identify a conserved quantity, <span>(mathcal {C})</span>, along the radial coordinate. Due to the complexity of the equations, exact analytical solutions are unattainable; therefore, we analyze the asymptotic behavior of the solutions both near the horizon and at infinity. We compute the conserved and thermodynamic quantities, including temperature, angular velocity, entropy, energy density, and angular momentum density. By evaluating the conserved quantity <span>(mathcal {C})</span> at both boundaries, we establish a direct relation between these thermodynamic variables, leading to a Smarr-type formula. We demonstrate that the first law of thermodynamics is rigorously satisfied for these rotating black branes. Furthermore, our analysis of thermal stability, based on the heat capacity and the Hessian determinant, reveals that the black brane solution is thermally unstable for the considered parameter space.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"58 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147733410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Tidal deformation bounds and perturbation transfer in bounded curvature spacetimes 有界曲率时空中的潮汐变形界和微扰传递

IF 2.8 4区物理与天体物理

General Relativity and Gravitation Pub Date : 2026-04-17 DOI: 10.1007/s10714-026-03546-x

Martin Drobczyk

{"title":"Tidal deformation bounds and perturbation transfer in bounded curvature spacetimes","authors":"Martin Drobczyk","doi":"10.1007/s10714-026-03546-x","DOIUrl":"10.1007/s10714-026-03546-x","url":null,"abstract":"<div><p>We derive two model-independent results for spacetimes with globally bounded tidal fields. These are operational resolution scales of the local-inertial approximation and tidal dynamics; no spacetime discreteness is implied. Given an invariant bound <span>(lambda _{max }le lambda _textrm{bound})</span> on the electric Riemann eigenvalues <span>(E_{ij}equiv R_{hat{0}ihat{0}j})</span> along freely falling worldlines, we prove (i) a rigorous upper bound on accumulated geodesic deviation through any bounded curvature interior, controlled by <span>(tau _*equiv lambda _{max }^{-1/2})</span>, and (ii) the existence of a critical wavenumber <span>(k_*sim tau _*^{-1})</span> separating adiabatic from non-adiabatic perturbation transfer through high-curvature epochs, with Bogoliubov coefficients exponentially suppressed for <span>(k,tau _*gg 1)</span>. Both results depend only on the tidal bound (and, for mode transfer, on a mild timescale assumption for the curvature-driven effective potential) and are otherwise insensitive to metric details. For preparation, we collect the standard operational consequences of bounded curvature, including the accuracy-dependent local-inertial domain <span>(L_textrm{LI}(varepsilon )sim sqrt{varepsilon }, lambda _{max }^{-1/2})</span> and, for conformally flat cores in four dimensions, the benchmark ratio <span>(tau _*/L_*=24^{1/4})</span> with <span>(L_*equiv K_{max }^{-1/4})</span>. We quantify the robustness of this coefficient under departures from maximal symmetry via the Weyl-to-Kretschmann ratio <span>(epsilon _C)</span>. The general framework is validated numerically in the extremal Hayward geometry.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"58 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10714-026-03546-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147702331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0