Rehabilitating space-times with NUTs

Clément, Gérard; Gal’tsov, D.V.; Guenouche, Mourad

doi:10.1016/j.physletb.2015.09.074

Cited by 107 publications

(130 citation statements)

References 19 publications

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“…As shown by some recent studies [9][10][11], Taub-NUT solution in Lorentzian setup does not lead to serious problems as imagined previously, and when establishing the Smarr relation and first law of thermodynamics, the core ingredient is to introduce a pair of novel conjugate thermodynamic quantities, namely the Misner potential and charge ψ-N [12,16] to ensure that the NUT parameter n varies independently. The thermodynamics of the uncharged Lorentzian Taub-NUT-AdS maintaining the Misner strings present has been formulated, and from the Komar integral notions, it turns out that ψ is actually the surface gravity of the Misner strings and N is interpreted as the integration over it [16].…”

Section: Discussionmentioning

confidence: 89%

“…while the total angular momentum of the spacetime vanishes. According to the line element (9), the Killing vector of the horizon is manifestly given by…”

Section: Geometry Of Charged Taub-nut-ads Spacetimementioning

confidence: 99%

“…However, recent studies have demonstrated that the removal of Misner strings by imposing the periodicity of time coordinate in Euclidean setup is unnecessary in fact. Clément et al [9][10][11] illustrated that the Misner string singularities are far less problematic than previously thought and they argued that Lorentzian Taub-NUT solution without imposing the Misner time periodicity condition is geodesically complete. At the same time, despite the existence of regions with closed timelike curves, causality is not violated at all for geodesic observers, implying that Lorentzian Taub-NUT spacetimes with the Misner strings present may be physical in essence.…”

Section: Introductionmentioning

confidence: 99%

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General Smarr relation and first law of a NUT dyonic black hole

Chen

Jiang

2019

Phys. Rev. D

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In this paper, we investigate the thermodynamics of the charged NUT black hole with the Misner strings present in the Einstein-Maxwell gravity. We show that the Misner charge N can be obtained by performing Komar integration over the Misner strings in the presence of electric and magnetic charges and the corresponding Smarr relation and first law can also be naturally established based on this geometric perspective. Besides, we demonstrate that the electric and magnetic charges appearing in the first law and Smarr relation are contingent on the special choice of gauge freedom for the electric and magnetic potentials. We re-derive two different versions of thermodynamics according to distinct choices of gauge and furthermore, we try to formulate more general thermodynamic laws under other arbitrary choices of gauge and deduce the conditions necessary to satisfy the Smarr relations and first laws simultaneously.

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Section: Discussionmentioning

confidence: 89%

“…while the total angular momentum of the spacetime vanishes. According to the line element (9), the Killing vector of the horizon is manifestly given by…”

Section: Geometry Of Charged Taub-nut-ads Spacetimementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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General Smarr relation and first law of a NUT dyonic black hole

Chen

Jiang

2019

Phys. Rev. D

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“…In this interpretation, similarly to the infinitely thin, semi-infinite solenoid which generates the Dirac magnetic monopole, the Misner string is a truly physical (singular) material object: a distribution-valued gravimagnetic flux. We have shown that such Misner strings, contrary to previous statements in the literature, are transparent to geodesic motion and that, while they are surrounded by closed timelike curves, these cannot be geodesic [19,20,21]. Adopting this interpretation, a thermodynamics for NUTty black holes was suggested recently in a series of papers [22,23,24,25].…”

Section: Introductionmentioning

confidence: 79%

On the Smarr formulas for electrovac spacetimes with line singularities

Clément

Gal’tsov

2020

Physics Letters B

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Using the revised Komar-Tomimatsu approach, we derive Smarr mass formulas for stationary axisymmetric solutions of the Einstein-Maxwell equations containing line singularities (defects) on the polar axis. In terms of the rod structure associated with Weyl representation of the metric, the horizons and the defects are formally similar up to differences due to their timelike/spacelike character. We derive (previously unknown or incorrect) horizon and global Smarr formulas in presence of a Newman-Unti-Tamburino (NUT) parameter. To avoid the divergence of the Komar angular momentum of semi-infinite Dirac and Misner strings, it is necessary to use a symmetric tuning. We also note that the horizon mass Smarr formula does not include either magnetic charge, or NUT parameter, correcting some statements in the literature. The contribution of each Misner string to the total mass consists in an angular momentum term, an electric charge term, and a length term, which can also be presented as the product of the spacelike analogue of surface gravity and the area of the string. *

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“…Recently the physical significance of the NUT generalisation of lorenzian black holes solutions in general relativity has been partially rehabilitated, under certain assumptions [25]. Nevertheless there is a open discussion about the physical interpretation of the conical singularities, that may take place in the presence of the NUT parameter.…”

Section: Review Of the Ernst Generating Techniquementioning

confidence: 99%

Enhanced Ehlers transformation and the Majumdar-Papapetrou-NUT spacetime

Astorino

2020

J. High Energ. Phys.

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The transformation which adds (or removes) NUT charge when it is applied to electrovacuum, axisymmetric and stationary space-times is studied. After analysing the Ehlers and the Reina-Treves transformations we propose a new one more precise in the presence of the Maxwell electromagnetic field. As an example the Kerr-Newman-NUT black hole is obtained with the help of this enhanced transformation. Moreover a new analytical exact solution is built adding the NUT charge to the Majumdar-Papapetrou metric. It describes a stationary generalisation of an extreme couple of charged black holes. From the near-horizon analysis, its microscopic entropy, according to the Kerr/CFT correspondence, is found and the second law of black hole thermodynamics is discussed.

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Rehabilitating space-times with NUTs

Cited by 107 publications

References 19 publications

General Smarr relation and first law of a NUT dyonic black hole

General Smarr relation and first law of a NUT dyonic black hole

On the Smarr formulas for electrovac spacetimes with line singularities

Enhanced Ehlers transformation and the Majumdar-Papapetrou-NUT spacetime

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