General Relativity and Gravitation最新文献

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Editorial note to: On the motion of spinning particles in general relativity by Jean-Marie Souriau 编辑注释让-玛丽-苏里奥:论广义相对论中的旋转粒子运动
IF 2.1 4区 物理与天体物理
General Relativity and Gravitation Pub Date : 2024-10-21 DOI: 10.1007/s10714-024-03294-w
Thibault Damour, Patrick Iglesias-Zemmour
{"title":"Editorial note to: On the motion of spinning particles in general relativity by Jean-Marie Souriau","authors":"Thibault Damour,&nbsp;Patrick Iglesias-Zemmour","doi":"10.1007/s10714-024-03294-w","DOIUrl":"10.1007/s10714-024-03294-w","url":null,"abstract":"<div><p>The gravitational interaction of (classical and quantum) spinning bodies is currently the focus of many works using a variety of approaches. This note is a comment on a short paper by Jean-Marie Souriau, now reprinted in the GRG Golden Oldies collection. Souriau’s short 1970 note was a pioneering contribution to a symplectic description of the dynamics of spinning particles in general relativity which remained somewhat unnoticed. We explain the specificity of Souriau’s approach and emphasize its potential interest within the current flurry of activity on the gravitational interaction of spinning particles.\u0000</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"56 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452282","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
Republication of: On the motion of spinning particles in general relativity by Jean-Marie Souriau 再版:让-马里-苏里奥:论广义相对论中旋转粒子的运动
IF 2.1 4区 物理与天体物理
General Relativity and Gravitation Pub Date : 2024-10-21 DOI: 10.1007/s10714-024-03295-9
Jean-Marie Souriau
{"title":"Republication of: On the motion of spinning particles in general relativity by Jean-Marie Souriau","authors":"Jean-Marie Souriau","doi":"10.1007/s10714-024-03295-9","DOIUrl":"10.1007/s10714-024-03295-9","url":null,"abstract":"<div><p>This paper was a pioneering contribution to a symplectic description of the dynamics of spinning particles in general relativity which remained somewhat unnoticed. In particular, it introduced the pre-symplectic 2-form <span>(sigma )</span> describing the dynamics of spinning particles coupled to an Einsteinian curved background. The method throws light on approaches to spinning black holes and neutron stars.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"56 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452283","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 scale(s) of quantum gravity and integrable black holes 量子引力和可积分黑洞的尺度
IF 2.1 4区 物理与天体物理
General Relativity and Gravitation Pub Date : 2024-10-21 DOI: 10.1007/s10714-024-03318-5
Roberto Casadio
{"title":"The scale(s) of quantum gravity and integrable black holes","authors":"Roberto Casadio","doi":"10.1007/s10714-024-03318-5","DOIUrl":"10.1007/s10714-024-03318-5","url":null,"abstract":"<div><p>It is often argued that the Planck length (or mass) is the scale of quantum gravity, as shown by comparing the Compton length with the gravitational radius of a particle. However, the Compton length is relevant in scattering processes but does not play a significant role in bound states. We will derive a possible ground state for a dust ball composed of a large number of quantum particles entailing a core with the size of a fraction of the horizon radius. This suggests that quantum gravity becomes physically relevant for systems with compactness of order one for which the nonlinearity of General Relativity cannot be discarded. A quantum corrected geometry can then be obtained from the effective energy-momentum tensor of the core or from quantum coherent states for the effective gravitational degrees of freedom. These descriptions replace the classical singularity of black holes with integrable structures in which tidal forces remain finite and there is no inner Cauchy horizon. The extension to rotating systems is briefly mentioned.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"56 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452284","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 non-relativistic geometric trinity of gravity 非相对论几何三位一体引力
IF 2.1 4区 物理与天体物理
General Relativity and Gravitation Pub Date : 2024-10-18 DOI: 10.1007/s10714-024-03308-7
William J. Wolf, James Read, Quentin Vigneron
{"title":"The non-relativistic geometric trinity of gravity","authors":"William J. Wolf,&nbsp;James Read,&nbsp;Quentin Vigneron","doi":"10.1007/s10714-024-03308-7","DOIUrl":"10.1007/s10714-024-03308-7","url":null,"abstract":"<div><p>The geometric trinity of gravity comprises three distinct formulations of general relativity: (i) the standard formulation describing gravity in terms of spacetime curvature, (ii) the teleparallel equivalent of general relativity describing gravity in terms of spacetime torsion, and (iii) the symmetric teleparallel equivalent of general relativity (STEGR) describing gravity in terms of spacetime non-metricity. In this article, we complete a geometric trinity of non-relativistic gravity, by (a) taking the non-relativistic limit of STEGR to determine its non-relativistic analogue, and (b) demonstrating that this non-metric theory is equivalent to Newton–Cartan theory and its teleparallel equivalent, i.e., the curvature and the torsion based non-relativistic theories that are both geometrised versions of classical Newtonian gravity.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"56 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10714-024-03308-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449515","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
The initial moments of a Hořava-Lifshitz cosmological model 霍扎瓦-利夫希茨宇宙学模型的初始时刻
IF 2.1 4区 物理与天体物理
General Relativity and Gravitation Pub Date : 2024-10-15 DOI: 10.1007/s10714-024-03310-z
A. Oliveira Castro Júnior, G. Oliveira-Neto, G. A. Monerat
{"title":"The initial moments of a Hořava-Lifshitz cosmological model","authors":"A. Oliveira Castro Júnior,&nbsp;G. Oliveira-Neto,&nbsp;G. A. Monerat","doi":"10.1007/s10714-024-03310-z","DOIUrl":"10.1007/s10714-024-03310-z","url":null,"abstract":"<div><p>In the present work, we study the initial moments of a homogeneous and isotropic Friedmann-Lemaître-Robertson-Walker (FLRW) cosmological model, considering Hořava-Lifshitz (HL) as the gravitational theory. The matter content of the model is a radiation perfect fluid. In order to study the initial moments of the universe in the present model, we consider quantum cosmology. More precisely the quantum mechanical tunneling mechanism. In that mechanism, the universe appears after the wavefunction associated to that universe tunnels through a potential barrier. We started studying the classical model. We draw the phase portrait of the model and identify qualitatively all types of dynamical behaviors associated to it. Then, we write the Hamiltonian of the model and apply the Dirac quantization procedure to quantize a constrained theory. We find the appropriate Wheeler-DeWitt equation and solve it using the Wentzel-Kramers-Brillouin (WKB) approximation. Using the WKB solution, to the Wheeler-DeWitt equation, we compute the tunneling probabilities for the birth of that universe (<span>(TP_{WKB})</span>). Since the WKB wavefunction depends on the radiation energy (<i>E</i>) and the free parameters coming from the HL theory (<span>(g_c)</span>, <span>(g_r)</span>, <span>(g_s)</span>, <span>(g_Lambda )</span>), we compute the behavior of <span>(TP_{WKB})</span> as a function of <i>E</i> and all the HL’s parameters <span>(g_c)</span>, <span>(g_r)</span>, <span>(g_s)</span>, <span>(g_Lambda )</span>. As a new result, due to the HL theory, we notice that, in the present model, the universe cannot tunnel through the barrier close to the origin. It happens because that tunneling probability is nil. Therefore, here, the universe cannot starts from a zero size and is free from the big bang singularity.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"56 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142438743","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
Reissner–Nordstr(ddot{textrm{o}})m spacetimes in torsion modified gravity: isometries and perihelion precession 扭转修正引力中的 Reissner-Nordstr(ddottextrm{o}})m 时空:等距和近日点前移
IF 2.1 4区 物理与天体物理
General Relativity and Gravitation Pub Date : 2024-10-14 DOI: 10.1007/s10714-024-03315-8
Jitesh Kumar, Rohit Kumar Gupta, Supriya Kar, Nitish Rang, Sunita Singh
{"title":"Reissner–Nordstr(ddot{textrm{o}})m spacetimes in torsion modified gravity: isometries and perihelion precession","authors":"Jitesh Kumar,&nbsp;Rohit Kumar Gupta,&nbsp;Supriya Kar,&nbsp;Nitish Rang,&nbsp;Sunita Singh","doi":"10.1007/s10714-024-03315-8","DOIUrl":"10.1007/s10714-024-03315-8","url":null,"abstract":"<div><p>We analyze the orbits of a unit mass body in a background Reissner–Nordstr<span>(ddot{textrm{o}})</span>m (RN) black hole in <span>(d)</span> <span>(=)</span> <span>((3+1))</span> from the perspectives of Geometric Torsion (GT) modified gravity theory in <span>((4+1))</span> dimensional bulk. A 4-form flux in bulk GT theory in <span>(d)</span> <span>(=)</span> <span>((4+1))</span> has been shown to ensure a mass dipole correction to the <span>((3+1))</span> dimensional gravity theory by Gupta, Kar and Rang recently. We argue that the dipole correction contributes topologically to the known exact geometries in General Theory of Relativity (GTR). Furthermore, the topological correction has been identified with non-Newtonian potential underlying a <span>(B_2 wedge F_2)</span> coupling term to Einstein–Hilbert action. The winding numbers ensured by the <i>BF</i> coupling to <span>(d=(3+1))</span> action in the framework presumably provide a clue towards a tunneling instanton in theory.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"56 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431012","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
Non-degenerate metrics, hypersurface deformation algebra, non-anomalous representations and density weights in quantum gravity 量子引力中的非退化度量、超曲面变形代数、非反常表示和密度权重
IF 2.1 4区 物理与天体物理
General Relativity and Gravitation Pub Date : 2024-10-14 DOI: 10.1007/s10714-024-03313-w
T. Thiemann
{"title":"Non-degenerate metrics, hypersurface deformation algebra, non-anomalous representations and density weights in quantum gravity","authors":"T. Thiemann","doi":"10.1007/s10714-024-03313-w","DOIUrl":"10.1007/s10714-024-03313-w","url":null,"abstract":"<div><p>Classical General Relativity is a dynamical theory of spacetime metrics of Lorentzian signature. In particular the classical metric field is nowhere degenerate in spacetime. In its initial value formulation with respect to a Cauchy surface the induced metric is of Euclidian signature and nowhere degenerate on it. It is only under this assumption of non-degeneracy of the induced metric that one can derive the hypersurface deformation algebra between the initial value constraints which is absolutely transparent from the fact that the <i>inverse</i> of the induced metric is needed to close the algebra. This statement is independent of the density weight that one may want to equip the spatial metric with. Accordingly, the very definition of a non-anomalous representation of the hypersurface deformation algebra in quantum gravity has to address the issue of non-degeneracy of the induced metric that is needed in the classical theory. In the Hilbert space representation employed in Loop Quantum Gravity (LQG) most emphasis has been laid to define an inverse metric operator on the dense domain of spin network states although they represent induced quantum geometries which are degenerate almost everywhere. It is no surprise that demonstration of closure of the constraint algebra on this domain meets difficulties because it is a sector of the quantum theory which is classically forbidden and which lies outside the domain of definition of the classical hypersurface deformation algebra. Various suggestions for addressing the issue such as non-standard operator topologies, dual spaces (habitats) and density weights have been proposed to address this issue with respect to the quantum dynamics of LQG. In this article we summarise these developments and argue that insisting on a dense domain of non-degenerate states within the LQG representation may provide a natural resolution of the issue thereby possibly avoiding the above mentioned non-standard constructions.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"56 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10714-024-03313-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430959","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
Similarity solutions of inhomogeneous spherically symmetric spacetime with dust fluid and dark energy 非均质球对称时空与尘埃流体和暗能量的相似解
IF 2.1 4区 物理与天体物理
General Relativity and Gravitation Pub Date : 2024-10-14 DOI: 10.1007/s10714-024-03312-x
Ahmad H. Alkasasbeh, Belal Al-Khamaiseh, Suhail Khan, Ahmad T. Ali
{"title":"Similarity solutions of inhomogeneous spherically symmetric spacetime with dust fluid and dark energy","authors":"Ahmad H. Alkasasbeh,&nbsp;Belal Al-Khamaiseh,&nbsp;Suhail Khan,&nbsp;Ahmad T. Ali","doi":"10.1007/s10714-024-03312-x","DOIUrl":"10.1007/s10714-024-03312-x","url":null,"abstract":"<div><p>In this work, we investigated an inhomogeneous spherically symmetric star consisting of dust fluid and dark energy components. We obtained similarity solutions for the energy density of the inhomogeneous dust fluid <span>(rho (t,r))</span>, dark energy <span>(rho _{DE}(t,r))</span>, and the mass function inside the star <i>m</i>(<i>t</i>, <i>r</i>). The symmetries of Einstein field equations for this model are derived using the symmetry group analysis method, where the Einstein field equations have been reduced into nonlinear ordinary differential equations (NODEs). Some interesting explicit analytical solutions are obtained for the reduced NODEs. Consequently, a new class of similarity solutions has been obtained for the energy density of the inhomogeneous dust fluid and dark energy as functions of coordinates <i>t</i> and <i>r</i>. These solutions are obtained when the star is composed of both dust fluid and dark energy components, dark energy components only, and dust fluid only. When the star is composed of dust fluid only, we discussed the possibility of black hole formation by assuming that the collapsing star is not initially trapped. Graphical representations of some solutions are given and discussed in the last section.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"56 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431453","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
A Riemannian geometric approach for timelike and null spacetime geodesics 时间性和空时空大地线的黎曼几何方法
IF 2.1 4区 物理与天体物理
General Relativity and Gravitation Pub Date : 2024-10-12 DOI: 10.1007/s10714-024-03314-9
Marcos A. Argañaraz, Oscar Lasso Andino
{"title":"A Riemannian geometric approach for timelike and null spacetime geodesics","authors":"Marcos A. Argañaraz,&nbsp;Oscar Lasso Andino","doi":"10.1007/s10714-024-03314-9","DOIUrl":"10.1007/s10714-024-03314-9","url":null,"abstract":"<div><p>The geodesic motion in a Lorentzian spacetime can be described by trajectories in a 3-dimensional Riemannian metric. In this article we present a generalized Jacobi metric obtained from projecting a Lorentzian metric over the directions of its Killing vectors. The resulting Riemannian metric inherits the geodesics for asymptotically flat spacetimes including the stationary and axisymmetric ones. The method allows us to find Riemannian metrics in three and two dimensions plus the radial geodesic equation when we project over three different directions. The 3-dimensional Riemannian metric reduces to the Jacobi metric when static, spherically symmetric and asymptotically flat spacetimes are considered. However, it can be calculated for a larger variety of metrics in any number of dimensions. We show that the geodesics of the original spacetime metrics are inherited by the projected Riemannian metric. We calculate the Gaussian and geodesic curvatures of the resulting 2-dimensional metric, we study its near horizon and asymptotic limit. We also show that this technique can be used for studying the violation of the strong cosmic censorship conjecture in the context of general relativity.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"56 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10714-024-03314-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142411520","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
Self-gravitating anisotropic fluids. I: context and overview 自重力各向异性流体。I:背景和概述
IF 2.1 4区 物理与天体物理
General Relativity and Gravitation Pub Date : 2024-10-11 DOI: 10.1007/s10714-024-03289-7
Tom Cadogan, Eric Poisson
{"title":"Self-gravitating anisotropic fluids. I: context and overview","authors":"Tom Cadogan,&nbsp;Eric Poisson","doi":"10.1007/s10714-024-03289-7","DOIUrl":"10.1007/s10714-024-03289-7","url":null,"abstract":"<div><p>This paper is the first in a sequence of three devoted to the formulation of a theory of self-gravitating anisotropic fluids in both Newtonian and relativistic gravity. In this first paper we set the stage, place our work in the context of a vast literature on anisotropic stars in general relativity, and provide an overview of the results obtained in the remaining two papers. In the second paper we develop the Newtonian theory, inspired by a familiar example of an anisotropic fluid, the (nematic) liquid crystal, and apply the theory to the construction of Newtonian stellar models. In the third paper we port the theory to general relativity, and exploit it to obtain relativistic stellar models. In both cases, Newtonian and relativistic, the state of the fluid is described by the familiar variables of an isotropic fluid (such as mass density and velocity field), to which we adjoin a director vector, which defines a locally preferred direction within the fluid. The director field contributes to the kinetic and potential energies of the fluid, and therefore to its dynamics. Both the Newtonian and relativistic theories are defined in terms of an action functional; variation of the action gives rise to dynamical equations for the fluid and gravitational field. While each theory is formulated in complete generality, in these papers we apply them to the construction of stellar models by restricting the fluid configurations to be static and spherically symmetric. We find that the equations of anisotropic stellar structure are generically singular at the stellar surface. To avoid a singularity, we postulate the existence of a phase transition at a critical value of the mass density; the fluid is anisotropic at high densities, and goes to an isotropic phase at low densities. In the case of Newtonian stars, we find that sequences of equilibrium configurations terminate at a maximum value of the central density; beyond this maximum the density profile becomes multi-valued within the star, and the model therefore becomes unphysical. In the case of relativistic stars, this phenomenon typically occurs beyond the point at which the stellar mass achieves a maximum, and we conjecture that this point marks the onset of a dynamical instability to radial perturbations (as it does for isotropic stars). Also in the case of relativistic stars, we find that for a given equation of state and a given assignment of central density, anisotropic stellar models are always less compact than isotropic models.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"56 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142405026","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
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