Calculation of multipole moments of axistationary electrovacuum spacetimes

Fodor, Gyula; Filho, Etevaldo dos Santos Costa; Hartmann, Betti

doi:10.1103/physrevd.104.064012

Cited by 16 publications

(6 citation statements)

References 102 publications

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“…This, in our opinion, enriches the Ernst formalism conceptually, as the knowledge of the electromagnetic Ernst potential Φ = −A t + iB t supplies us directly with the explicit expressions of the physical components of the electromagnetic 4-potentials determining the intrinsic properties of the electromagnetic field, without the need of finding A ϕ . We notice in this respect that it is the component B t , and not A ϕ , that takes part for instance in the definition of the relativistic multipole moments of the electromagnetic field [17][18][19][20][21], which gives us another good illustration of a generic secondary role of the component A ϕ in the physical analysis.…”

Section: Discussionmentioning

confidence: 95%

Dyonic black holes: The theory of two electromagnetic potentials. II

García-Compeán¹,

Manko²,

Ramírez-Valdez³

2023

Preprint

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The results obtained in our previous paper are now extended to the case of stationary axially symmetric dyonic black boles within the theory of two electromagnetic potentials. We slightly enlarge the classical Ernst formalism by introducing, with the aid of the t-and ϕ-components of the dual potential B µ , the magnetic potential Φ m which, similar to the known electric potential Φ e , also takes constant value on the black hole horizon. We analyze in detail the case of the dyonic Kerr-Newman black hole and show how the Komar mass must be evaluated correctly in this stationary dyonic model. In particular, we rigorously prove the validity of the standard Tomimatsu mass formula and point out that attempts to "improve" it made in recent years are explained by misunderstanding of the auxiliary role that singular potentials play in the description of magnetic charges. Our approach is symmetrical with respect to electric and magnetic charges and, like in the static case considered earlier, Dirac strings of all kind are excluded from the physical picture of the stationary black hole dyonic spacetimes.

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Section: Discussionmentioning

confidence: 95%

Dyonic black holes: The theory of two electromagnetic potentials. II

García-Compeán¹,

Manko²,

Ramírez-Valdez³

2023

Preprint

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“…To date, the electrovac algorithm has not been used to explicitly determine the metric with a set of massive, spin, and electromagnetic multipoles. The Hoenselaers-Perjés method had two mistakes, the first one was found by Sotiriou and Apostolatos [29], and the second one by Perjés [30,31,32]. In this contribution, we present approximate solutions of the EME.…”

Section: Introductionmentioning

confidence: 94%

Approximate Kerr-Newman-like metric with quadrupole

Frutos─Alfaro

Gómez-Ovares

Montero-Camacho

2021

RMTA

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The Kerr metric is known to have issues when trying to find a physical interior solution. In this work we continue our efforts to construct a more realistic exterior metric for astrophysical objects. A new approximate metric representing the spacetime of a charged, rotating and slightly-deformed body is obtained by perturbing the Kerr-Newman metric to include the mass-quadrupole and quadrupole-quadrupole orders. It has a simple form because it is Kerr-Newman-like.

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“…Asymptotically flat, four-dimensional, stationary metrics have two families of coordinateindependent multipole moments; these were first described by Geroch [1] and Hansen [2] for vacuum solutions, and later generalized in various ways [5,15,[28][29][30]. Thorne later introduced the notion of asymptotically Cartesian and mass-centered (ACMC) coordinates, in which a stationary, axisymmetric metric 1 has the particular asymptotic expansion in JHEP02(2023)160 powers of 1/r:…”

Section: Gravitational Multipolesmentioning

confidence: 99%

On supersymmetric multipole ratios

Ganchev

Mayerson

2023

J. High Energ. Phys.

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Four-dimensional supersymmetric black holes are static and so have all vanishing multipoles (except the mass monopole). Nevertheless, it is possible to define finite multipole ratios for these black holes, by taking the ratio of (finite) multipoles of supersymmetric multicentered geometries and then taking the black hole scaling limit of the multipole ratios within these geometries. An alternative way to calculate these multipole ratios is to deform the supersymmetric black hole slightly into a non-extremal, rotating black hole, calculate the multipole ratios of this altered black hole, and then take the supersymmetric limit of the ratios. Bena and Mayerson observed that for a class of microstate geometries, these two a priori completely different methods give spectacular agreement for the resulting supersymmetric black hole multipole ratios. They conjectured that this agreement is due to the smallness of the entropy parameter for these black holes. We correct this conjecture and give strong evidence supporting a more refined conjecture, which is that the agreement of multipole ratios as calculated with these two different methods is due to both the microstate geometry and its corresponding black hole having a property we call “large dipole”, which can be interpreted as their center of mass being far away from its apparent center.

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Calculation of multipole moments of axistationary electrovacuum spacetimes

Cited by 16 publications

References 102 publications

Dyonic black holes: The theory of two electromagnetic potentials. II

Dyonic black holes: The theory of two electromagnetic potentials. II

Approximate Kerr-Newman-like metric with quadrupole

On supersymmetric multipole ratios

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