On asymptotically flat space-times

A class of solutions of the low energy string theory in four dimensions is studied. This class admits a geodesic, shear-free null congruence which is non-twisting but in general diverging and the corresponding solutions in Einstein's theory form the Robinson-Trautman family together with a subset of the Kundt's class. The Robinson-Trautman conditions are found to be frame invariant in string theory. The Lorentz Chern-Simons three form of the stringy Robinson-Trautman solutions is shown to be always closed. The stringy generalizations of the vacuum Robinson-Trautman equation are obtained and three subclasses of solutions are identified. One of these subclasses exists, among all the dilatonic theories, only in Einstein's theory and in string theory. Several known solutions including the dilatonic black holes, the pp-waves, the stringy C-metric and certain solutions which correspond to exact conformal field theories are shown to be particular members of the stringy Robinson-Trautman family. Some new solutions which are static or asymptotically flat and radiating are also presented. The radiating solutions have a positive Bondi mass. One of these radiating solutions has the property that it settles down smoothly to a black hole state at late retarded times.

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“…one has 19) where q is the fourth parameter appearing in the solution. The metric function H is now expressible as…”

Section: The Field Equationsmentioning

confidence: 99%

“…in [19]. Using (3.15)-(3.17) it is, of course, possible to represent these solutions in alternative gauges where M is constant but D and Q are functions of u or where D is constant but M and Q are functions of u.…”

Section: New Radiating Solutionsmentioning

confidence: 99%

Stringy Robinson-Trautman solutions

Güven

Yörük

1996

Phys. Rev. D

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“…This does not always happen, two examples are: Krasiński's (1983) [10] analysis of the Stephani universe where r = ∞ labels a second center of symmetry, and type B Bekenstein conformal scalar extensions of ordinary scalar field solutions, Agnese and LaCamera (1985) [11], and Roberts (1996) [12], which have bizarre asymptotic properties. More rigorous definitionsof asymptotic flatness are give in Ludwig (1975) [13] and Reiris (2014) [14]. The result follows from the conservation equations so that it is explicitly independent of the gravitational field equations used.…”

Section: Asymptotic Flatnessmentioning

confidence: 99%

“…This problem could also be studied numerically or in terms of Weyl and Ricci scalars Ludwidg (1975) [13]. The rate of decay of scalar fields has been discussed in the last paragraph of the introduction of [12].…”

Section: Rates Of Decaymentioning

confidence: 99%

Spacetime Exterior to a Star: Against Asymptotic Flatness

Roberts¹

2016

Open Physics

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Abstract:In many circumstances the perfect fluid conservation equations can be directly integrated to give a geometric-thermodynamic equation: typically that the lapse N is the reciprocal of the enthalphy h, (N = 1/h). This result is aesthetically appealing as it depends only on the fluid conservation equations and does not depend on specific field equations such as Einstein's. Here the form of the geometric-thermodynamic equation is derived subject to spherical symmetry and also for the shift-free ADM formalism. There at least three applications of the geometric-thermodynamic equation, the most important being to the notion of asymptotic flatness and hence to spacetime exterior to a star. For asymptotic flatness one wants h → 0 and N → 1 simultaneously, but this is incompatible with the geometric-thermodynamic equation. Observational data and asymptotic flatness are discussed. It is argued that a version of Mach's principle does not allow asymptotic flatness.

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“…The approach we take is that of Penrose's (1968) conformal method which has been used successfully several times before (see Ludwig 1976Ludwig , 1978Ludwig , 1980a in the derivation of solutions to the Einstein equations in the real case. In particular, in one of these papers (Ludwig 1980b), the method was employed to find a further extension of Kundt's (1961) generalisation of plane gravitational waves.…”

Section: Introductionmentioning

confidence: 99%

Preionization of a CO₂laser gas mixture byαparticles

Glushchenko¹,

Lavrentyuk²

1986

Sov. J. Quantum Electron.

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One of the two classes of non-diverging algebraically special left-flat spaces found by Fette, Janis and Newman is generalised by allowing the (self-dual part of the) Weyl tensor to become algebraically general. Penrose's conformal approach is used, thereby allowing the desired asymptotic behaviour of the solutions to be prescribed from the outset. The 'solutions' are, however, still subject to some 'reduced equations'. For a specific choice of initial data at conformal null infinity these reduced equations simplify to Plebanski's second heavenly equation.

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On asymptotically flat space-times

Cited by 34 publications

References 11 publications

Stringy Robinson-Trautman solutions

Stringy Robinson-Trautman solutions

Spacetime Exterior to a Star: Against Asymptotic Flatness

Preionization of a CO₂laser gas mixture byαparticles

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On asymptotically flat space-times

Cited by 34 publications

References 11 publications

Stringy Robinson-Trautman solutions

Stringy Robinson-Trautman solutions

Spacetime Exterior to a Star: Against Asymptotic Flatness

Preionization of a CO2laser gas mixture byαparticles

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Product

Resources

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Preionization of a CO₂laser gas mixture byαparticles