Cosmological test of the Yilmaz theory of gravity

Ibison, Michael

doi:10.1088/0264-9381/23/3/001

Cited by 21 publications

(19 citation statements)

References 28 publications

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“…12) we observe that the curve L c (r c , m) has a minimum at r c = 3 +√ 5 m where L min ≈ 3.523216438 m. (See Figure 2.) The graph shows the angular momentum L/m required to establish a circular orbit at radius r/m.…”

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confidence: 73%

Exponential metric represents a traversable wormhole

et al. 2018

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For various reasons a number of authors have mooted an "exponential form" for the spacetime metric: ds 2 = −e −2m/r dt 2 + e +2m/r {dr 2 + r 2 (dθ 2 + sin 2 θ dφ 2 )}.While the weak-field behaviour matches nicely with weak-field general relativity, and so also automatically matches nicely with the Newtonian gravity limit, the strong-field behaviour is markedly different. Proponents of these exponential metrics have very much focussed on the absence of horizons -it is certainly clear that this geometry does not represent a black hole. However, the proponents of these exponential metrics have failed to note that instead one is dealing with a traversable wormhole -with all of the interesting and potentially problematic features that such an observation raises. If one wishes to replace all the black hole candidates astronomers have identified with traversable wormholes, then certainly a careful phenomenological analysis of this quite radical proposal should be carried out.

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confidence: 73%

Exponential metric represents a traversable wormhole

et al. 2018

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“…with the magnitude of scalar charge reduced to the central mass [20]. The transfer from the JNW solution (7) to the isotropic Papapetrou metric (10) simultaneously transforms the system (3) into (4) and induces the transfer from scalar potential (8) to antiscalar potential (12), and such operation is unique. This implies that all masses might be considered as sources of (anti)scalar field (cf.…”

Section: Scalar-to-antiscalar Transitionmentioning

confidence: 99%

Simpler than vacuum: Antiscalar alternatives to black holes

Makukov

Mychelkin

2018

Phys. Rev. D

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The Janis-Newman-Winicour and Papapetrou metrics represent counterparts to the Schwarzschild black hole with scalar and antiscalar background fields, correspondingly (where "anti" is to be understood as in "anti-de Sitter"). There is also a scalar counterpart (the Krori-Bhattacharjee metric) to the Kerr black hole. Here we study analytical connections between these solutions and obtain the exact rotational generalization of the antiscalar Papapetrou spacetime as a viable alternative to the Kerr black hole. The antiscalar metrics appear to be the simplest ones as they do not reveal event horizons and ergospheres, and they do not involve an extra parameter for scalar charge. Static antiscalar field is thermodynamically stable and self-consistent, but this is not the case for the scalar Janis-Newman-Winicour solution; besides, antiscalar thermodynamics is reducible to black-hole thermodynamics. Lensing, geodetic and Lense-Thirring effects are found to be practically indistinguishable between antiscalar and vacuum solutions in weak fields. Only strongfield observations might provide a test for the existence of antiscalar background. In particular, the antiscalar solution predicts 5% larger shadows of supermassive compact objects, as compared to the vacuum solution. Another measurable aspect is the 6.92% difference in the frequency of the innermost stable circular orbit, characterizing the upper cut-off in the gravitational wave spectrum.

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“…In this approach the metric field can be characterized by a background spacetime conformally flat affected by a disturbance. We have approached some examples in this tensorial structure that results in exponential metric fields, we can point out as the main exponential metric obtained in this paper which has been extensively explored: the Yilmaz exponential metric (Yilmaz 1958(Yilmaz , 1992(Yilmaz , 1976(Yilmaz , 1982(Yilmaz , 1973(Yilmaz , 1977(Yilmaz , 1997Clapp 1973;Robertson 1999aRobertson , 1999bIbison 2006). H. Yilmaz has argued that in his theory, the gravitational field can be quantized via Feynman's method (Yilmaz 1995;Alley 1995).…”

Section: Resultsmentioning

confidence: 89%

“…Robertson argues that neutron star with mass ∼10M is found for Yilmaz metric while that an object of nuclear density greater than ∼2.8M should be a black hole in Schwarzschild metric. Ibison has tested Yilmaz theory by working out the corresponding Friedmann equations generated by assuming the Friedmann-RobertsonWalker cosmological metrics (Ibison 2006). There are a series of claims and counter-claims involving Fackerell (Fackerell 1996;Yilmaz 1994;Alley and Yilmaz 2000), and also Misner and Wyss (Wyss and Misner 1999;Misner 1999;Alley and Yilmaz 1999) about Yilmaz theory.…”

Section: Yilmaz Metricmentioning

confidence: 99%

Exponential metric fields

Santos

2010

Astrophys Space Sci

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The Laser Interferometer Space Antenna (LISA) mission will use advanced technologies to achieve its science goals: the direct detection of gravitational waves, the observation of signals from compact (small and dense) stars as they spiral into black holes, the study of the role of massive black holes in galaxy evolution, the search for gravitational wave emission from the early Universe. The gravitational red-shift, the advance of the perihelion of Mercury, deflection of light and the time delay of radar signals are the classical tests in the first order of General Relativity (GR). However, LISA can possibly test Einstein's theories in the second order and perhaps, it will show some particular feature of non-linearity of gravitational interaction. In the present work we are seeking a method to construct theoretical templates that limit in the first order the tensorial structure of some metric fields, thus the non-linear terms are given by exponential functions of gravitational strength. The Newtonian limit obtained here, in the first order, is equivalent to GR.

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Cosmological test of the Yilmaz theory of gravity

Cited by 21 publications

References 28 publications

Exponential metric represents a traversable wormhole

Exponential metric represents a traversable wormhole

Simpler than vacuum: Antiscalar alternatives to black holes

Exponential metric fields

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