General Relativity and Gravitation最新文献

{"title":"Flat subspaces of the (SL(n,mathbb {R})) chiral equations","authors":"I. A. Sarmiento-Alvarado,&nbsp;P. Wiederhold,&nbsp;T. Matos","doi":"10.1007/s10714-025-03467-1","DOIUrl":"10.1007/s10714-025-03467-1","url":null,"abstract":"<div><p>In this work, we introduce a method for finding exact solutions to the vacuum Einstein field equations in higher dimensions from a given solution to the chiral equation. When considering a <span>(n + 2)</span>-dimensional spacetime with <i>n</i> commutative Killing vectors, the metric tensor can take the form <span>(hat{g} = f ( rho , zeta ) ( d rho ^2 + d zeta ^2 ) + g_{mu nu } ( rho , zeta ) d x^mu d x^nu )</span>. Then, the Einstein field equations in vacuum reduce to a chiral equation, <span>(( rho g_{, z} g ^{-1} )_{, bar{z}} + ( rho g_{, bar{z}} g ^{-1} )_{, z} = 0)</span>, and two differential equations, <span>(( ln f rho ^{1-1/n} )_{, Z} = frac{rho }{2} operatorname {tr} ( g_{, _Z} g^{-1} )^2)</span>, where <span>(g in SL( n, mathbb {R} ))</span> is the normalized matrix representation of <span>(g_{mu nu })</span>, <span>(z = rho + i zeta )</span> and <span>(Z = z, bar{z})</span>. We use the ansatz <span>(g = g ( xi ^a ))</span>, where the parameters <span>(xi ^a)</span> depend on <i>z</i> and <span>(bar{z})</span> and satisfy a generalized Laplace equation, <span>(( rho xi ^a _{, z} )_{, bar{z}} + ( rho xi ^a _{, bar{z}} )_{, z} = 0)</span>. The chiral equation to the Killing equation, <span>(A_{a, xi ^b} + A_{b, xi ^a} = 0)</span>, where <span>(A_a = g_{, xi ^a} g^{-1})</span>. Furthermore, we assume that the matrices <span>(A_a)</span> commute with each other; in this way, they fulfill the Killing equation.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10714-025-03467-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145090360","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}

{"title":"Topical Collection – Hyperboloidal foliations in the era of gravitational-wave astronomy: from mathematical relativity to astrophysics","authors":"David Hilditch,&nbsp;Rodrigo Panosso Macedo,&nbsp;Alex Vañó-Viñuales,&nbsp;Anıl Zenginoğlu","doi":"10.1007/s10714-025-03466-2","DOIUrl":"10.1007/s10714-025-03466-2","url":null,"abstract":"","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037348","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}

{"title":"Riemannian geometry reframed as a generalized lie algebra to integrate general relativity with the standard model","authors":"Joseph E. Johnson","doi":"10.1007/s10714-025-03461-7","DOIUrl":"10.1007/s10714-025-03461-7","url":null,"abstract":"<div><p>This paper is based upon the <u>observation</u> that the translation operator D in a curved space–time must depend upon the position of the particle and thus one must allow the [D, X] commutator to be a function of position X in a generalized Lie algebra. This work consists of two parts; In a purely mathematical development, we first reframe Riemannian geometry (RG) as a Generalized Lie algebra (GLA) by allowing the structure constants to be functions of an Abelian subalgebra as is necessary when translations in a space of n variables depend upon the position in the space. In the second part we show that Einstein’s equations for General Relativity (GR) can now be written as commutation relations in this GLA framework including relativistic Quantum Theory (QT) and the Standard Model (SM) with novel predictions. We begin with an Abelian Lie algebra of n “position” operators, X, whose simultaneous eigenvalues, y, define a real n-dimensional space R(n) with a Hilbert space representation. Then with n new operators defined as independent functions, X^′(X), we define contravariant and covariant tensors in terms of their eigenvalues, y and y^′ with Dirac notation. We then define n additional operators, D, whose exponential map is, by definition, to translate X in a noncommutative algebra of operators (observables) where the “structure constants” are shown to be the metric functions of the X operators to allow for spatial curvature. The D operators then have a Hilbert space position-diagonal representation as a generalized differential operator plus a Christoffel symbol, Γ^µ (y), an arbitrary vector function A^µ (y), and the derivative of a scalar function g^µn∂ϕ(y)/∂yⁿ. One can then express the Christoffel symbols, and the Riemann, Ricci, and other tensors as commutators in this representation thereby framing RG as a GLA. We then show that this GLA provides a more general framework for RG to support GR, QT, the SM with novel predictions.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10714-025-03461-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145028399","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}

{"title":"Anisotropic Spacetimes in f(G)-gravity: Bianchi I, Bianchi III and Kantowski-Sachs Cosmologies","authors":"R. S. Bogadi,&nbsp;A. Giacomini,&nbsp;M. Govender,&nbsp;C. Hansraj,&nbsp;G. Leon,&nbsp;A. Paliathanasis","doi":"10.1007/s10714-025-03465-3","DOIUrl":"10.1007/s10714-025-03465-3","url":null,"abstract":"<div><p>We investigate the evolution of cosmological anisotropies within the framework of <span>(fleft( Gright) )</span>-gravity. Specifically, we consider a locally rotationally symmetric geometry in four-dimensional spacetime that describes the Bianchi I, Bianchi III, and the Kantowski-Sachs spacetimes. Within this context, we introduce a Lagrange multiplier which allows us to reformulate the geometric degrees of freedom in terms of a scalar field. The resulting theory is dynamically equivalent to an Einstein-Gauss-Bonnet scalar field model. We normalize the field equations by introducing dimensionless variables. The dynamics of our system is then explored by solving the resulting nonlinear differential equations numerically for various sets of initial conditions. Our analysis reveals the existence of two finite attractors: the Minkowski universe and an isotropic, spatially flat solution capable of describing accelerated expansion. Although de Sitter expansion may be recovered, it appears only as an unstable solution. In addition, the theory suffers from the existence of Big Rip singularities.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005490","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}

{"title":"Investigating the gravitational coupling of leptons via precision measurements of G","authors":"Marco Bruschi,&nbsp;Per Grafström","doi":"10.1007/s10714-025-03459-1","DOIUrl":"10.1007/s10714-025-03459-1","url":null,"abstract":"<div><p>In recent decades, the precision of gravitational constant measurements has signifi-cantly improved. In this letter, we propose a method that takes advantage of the improved precision to measure in the laboratory whether leptons generate gravity in the same way as baryons. If leptons did not generate gravity, there would be a fractional difference in the value of the gravitational constant <i>G</i> expected for two different materials with different <span>(frac{Z}{A})</span> ratios, where <i>A</i> and <i>Z</i> represent the mass and atomic number, respectively. We propose suitable pairs of materials where such a difference could be detected at about <span>(4 sigma )</span> level given the precision in the present measurements of <i>G</i>.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144928678","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}

{"title":"The limits of cosmology","authors":"Joseph Silk","doi":"10.1007/s10714-025-03450-w","DOIUrl":"10.1007/s10714-025-03450-w","url":null,"abstract":"<div><p>The Moon is our future. It may seem like a chimera with a projected cost in excess of 100 billion$, and counting, dispensed on ARTEMIS with little to show to date. However it is the ideal site for the largest telescopes that we can dream about, at wavelengths spanning decimetric radio through optical to terahertz FIR. And it is these future telescopes that will penetrate the fundamental mysteries of the first hydrogen clouds, the first stars, the first galaxies, the first supermassive black holes, and the nearest habitable exoplanets. Nor does it stop there. Our lunar telescopes will take us back to the first months of the Universe, and even back to the first 10<span>(^{-36})</span> second after the Big Bang when inflation most likely occurred. Our lunar telescopes will provide high resolution images of exoplanets that are nearby Earth-like ’twins’ and provide an unrivalled attempt to answer the ultimate cosmic question of whether we are alone in the universe. Here I will set out my vision of the case for lunar astronomy over the next several decades.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 8","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10714-025-03450-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144905046","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}

{"title":"Dirac stars with wormhole topology","authors":"Vladimir Dzhunushaliev,&nbsp;Vladimir Folomeev,&nbsp;Sayabek Sakhiyev","doi":"10.1007/s10714-025-03463-5","DOIUrl":"10.1007/s10714-025-03463-5","url":null,"abstract":"<div><p>We consider configurations consisting of a gravitating nonlinear spinor field and a massless ghost scalar field providing a nontrivial spacetime topology. For such a mixed system, we have constructed families of asymptotically flat asymmetric solutions describing Dirac stars with wormhole topology. The physical properties of such systems are completely determined by the values of three input quantities: the nonlinearity parameter of the spinor field, the spinor frequency, and the throat parameter. Depending on the specific values of these parameters, the configurations may be regular or singular and possess one or two throats, as well as they may contain possible horizons of different kinds. Furthermore, because of the asymmetry, masses and sizes of the configurations observed at the two asymptotic ends of the wormhole may differ considerably. For large negative values of the nonlinearity parameter, it is possible to obtain configurations whose masses are comparable to the Chandrasekhar mass and effective radii are of the order of kilometers.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 8","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894023","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}

{"title":"Einstein-Yang-Mills Regular Black Holes in Rainbow Gravity","authors":"Celio R. Muniz,&nbsp;Francisco Bento Lustosa,&nbsp;Takol Tangphati","doi":"10.1007/s10714-025-03458-2","DOIUrl":"10.1007/s10714-025-03458-2","url":null,"abstract":"<div><p>In this work, we investigate regular black hole solutions in nonminimal Einstein-Yang-Mills theory modified by Rainbow Gravity, focusing on the impact of quantum gravity effects on their thermodynamics, particle emission, energy conditions, curvature, and shadow formation. We find that the rainbow parameter <span>(lambda )</span> alters Hawking’s temperature, entropy, and specific heat, leading to modified phase transitions and the possible formation of remnants. We also calculate the lower bound for the greybody factor demonstrating that particle emission is enhanced with increasing <span>(lambda )</span>, reflecting the behavior of the temperature and confirming the impact of the rainbow parameter on the evaporation process. Energy conditions are violated inside the black hole, with violations intensifying for larger <span>(lambda )</span>. We also show that Rainbow Gravity mitigates singularity formation by softening the curvature near the origin, contributing to the regularity of the solution. Finally, we have investigated the black hole shadow and shown that its radius can either increase or decrease as quantum gravity effects become more pronounced, depending on the specific parameter configuration. This behavior suggests that black hole shadow observations may offer a promising avenue for testing the phenomenological implications of Rainbow Gravity. These results highlight the role of Rainbow Gravity in modifying black hole physics and provides a framework for exploring quantum gravitational corrections in astrophysical scenarios.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 8","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144887988","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}

{"title":"Fundamental complement of a gravitating region","authors":"Raphael Bousso,&nbsp;Sami Kaya","doi":"10.1007/s10714-025-03462-6","DOIUrl":"10.1007/s10714-025-03462-6","url":null,"abstract":"<div><p>Any gravitating region <i>a</i> in any spacetime gives rise to a generalized entanglement wedge, the hologram <i>e</i>(<i>a</i>). Holograms exhibit properties expected of fundamental operator algebras, such as strong subadditivity, nesting, and no-cloning. But the entanglement wedge <span>({{,textrm{EW},}})</span> of an AdS boundary region <i>B</i> with commutant <span>({{bar{B}}})</span> satisfies an additional condition, complementarity: <span>({{,textrm{EW},}}(B))</span> is the spacelike complement of <span>({{,textrm{EW},}}(bar{B}))</span> in the bulk. Here we identify an analogue of the boundary commutant <span>({{bar{B}}})</span> in general spacetimes: given a gravitating region <i>a</i>, its <i>fundamental complement</i> <span>({{tilde{a}}})</span> is the smallest wedge that contains all infinite world lines contained in the spacelike complement <span>(a')</span> of <i>a</i>. We refine the definition of <i>e</i>(<i>a</i>) by requiring that it be spacelike to <span>({{tilde{a}}})</span>. We prove that <i>e</i>(<i>a</i>) is the spacelike complement of <span>(e({{tilde{a}}}))</span> when the latter is computed in <span>(a')</span>. We exhibit many examples of <span>({{tilde{a}}})</span> and of <i>e</i>(<i>a</i>) in de Sitter, flat, and cosmological spacetimes. We find that a Big Bang cosmology (spatially closed or not) is trivially reconstructible: the whole universe is the entanglement wedge of any wedge inside it. But de Sitter space is not trivially reconstructible, despite being closed. We recover the AdS/CFT prescription by proving that <span>({{,textrm{EW},}}(B)=e()</span>causal wedge of <i>B</i>).</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 8","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144868948","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}

{"title":"Constraints on Quantum Gravity","authors":"Hirosi Ooguri","doi":"10.1007/s10714-025-03455-5","DOIUrl":"10.1007/s10714-025-03455-5","url":null,"abstract":"<div><p>Recently, it has become increasingly clear that there are constraints on the low-energy effective theories of quantum gravity that cannot be captured by the standard Wilsonian paradigm. For gravitational theories in asymptotically anti-de Sitter spacetimes, we can formulate such constraints and aim to prove or falsify them using the AdS/CFT correspondence. I will review the work I did with Daniel Harlow on constraints on symmetries of quantum gravity. I will also discuss more recent progress in this holographic approach, and present the proof that Yifan Wang and I completed this year, which proves and strengthens a part of the Distance Conjecture that I proposed with Cumrun Vafa in 2006.</p></div>","PeriodicalId":578,"journal":{"name":"General Relativity and Gravitation","volume":"57 8","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10714-025-03455-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144861560","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}