Static, spherically symmetric black holes and compact objects without an event horizon have unstable (stable) circular orbits of a light called photon (antiphoton) sphere. A Damour-Solodukhin wormhole has been suggested as a simple black hole mimicker and the difference of its metric tensors from a black hole is described by a dimensionless parameter $λ$. The wormhole with two flat regions has two photon spheres and an antiphoton sphere for $λ<\sqrt{2}/2$ and a photon sphere for $λ\geq \sqrt{2}/2$. When the parameter $λ$ is $\sqrt{2}/2$, the photon sphere is marginally unstable because of degeneration of the photon spheres and antiphoton sphere. We investigate gravitational lensing by the wormhole in weak and strong gravitational fields. We find that the deflection angle of a light ray reflected by the marginally unstable photon sphere diverges nonlogarithmically in a strong deflection limit for $λ=\sqrt{2}/2$, while the deflection angle reflected by the photon sphere diverges logarithmically for $λ\neq \sqrt{2}/2$. We extend a strong deflection limit analysis for the nonlogarithmic divergence case. We expect that our method can be applied for gravitational lenses by marginally unstable photon spheres of various compact objects.
The purpose of this Comment is to point out that there are conceptual and mathematical flaws in the analysis in "Light deflection by Damour-Solodukhin wormholes and Gauss-Bonnet theorem, Phys. Rev. D 98, 044033 (2018) by Ali Övgün".
We reply to the Comment of Bhattacharya and Karimov on our paper Light deflection by Damour-Solodukhin wormholes and Gauss-Bonnet theorem [arXiv:1811.00768 [gr-qc]]. We address a number of incorrect claims made about our calculations and methodology. We show below that the claims of BK are incorrect, and that there are no problems with the results of Övgün's paper or its implications.
In this paper, using the recent method proposed by Ono, Ishihara and Asada (OIA) who extend the idea of Gibbons and Werner to the stationary and axisymmetric case, we apply the Gauss-Bonnet theorem to the optical metric of the non-rotating and rotating Damour-Solodukhin wormholes spacetimes to study the weak gravitational lensing by these objects. Furthermore, we study the strong gravitational lensing by the non-rotating Damour-Solodukhin wormholes using the Bozza's method to see the differences between the weak lensing and the strong lensing. We demonstrate the relation between the strong def…
The static traversable wormhole should made out of some type of exotic matter which satisfies the Morris-Thorne conditions. Although the characteristic size of the region with the exotic matter can be made arbitrary small, the calculations performed so far suggest that the Morris-Thorne conditions are quite restrictive and it is hard to find matter with the desired properties. Traditionally, the quantized fields are considered as the best candidates because they can violate the weak-energy condition. In this paper we employ the Schwinger-DeWitt expansion to construct and examine the approximat…
Institute of Molecule and Crystal Physics, Ufa Federal Research Centre, Russian Academy of Sciences（俄罗斯科学院乌法联邦研究中心分子与晶体物理研究所）；Zel’dovich International Center for Astrophysics, M. Akmullah Bashkir State Pedagogical University（M.阿卜穆拉巴什基尔国立师范大学扎尔多维奇天体物理学国际中心）；Department of Mathematics, Kidderpore College（基德波尔学院数学系）
A new rotating generalization of the Damour-Solodukhin wormhole (RDSWH), called Kerr-like wormhole, has recently been proposed and investigated by Bueno \textit{et al} for echoes in the gravitational wave signal. We show a novel feature of the RDSWH, viz., that the kinematic properties such as the ISCO\ or marginally stable radius $r_{\text{ms}}$, efficiency $ε$ and the disk potential $V_{\text{eff}}$ are \textit{independent} of $λ$ (which means they are identical to their KBH counterparts for any given spin). Differences however appear in the emissivity properties for higher values $0.1<λ\leq…
Reflectionless and echo modes in asymmetric Damour-Solodukhin wormholes
Escola de Engenharia de Lorena, Universidade de São Paulo（圣保罗大学洛雷纳工程学院）；Center for Gravitation and Cosmology, College of Physical Science and Technology, Yangzhou University（扬州大学物理科学与技术学院引力与宇宙学研究中心）；Faculdade de Engenharia de Guaratinguetá, Universidade Estadual Paulista（圣保罗州立大学瓜拉廷格塔工程学院）；Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Synergetic Innovation Center for Quantum Effects and Applications, and Department of Physics, Hunan Normal University（湖南师范大学物理学院低维量子结构与量子控制教育部重点实验室、量子效应与应用协同创新中心）；Metropolitan State University（大都会州立大学）；Department of Physical Sciences and Applied Mathematics, Vanguard University（先锋大学物理科学与应用数学系）
A Damour-Solodukhin wormhole with a metric which is similar to a Schwarzschild black hole seems to be a black hole mimicker since it is difficult to distinguish them by practical astrophysical observations. In this paper, we investigate a center-of-mass energy for the collision of two test particles in the Damour-Solodukhin wormhole spacetime. We show that the center-of-mass energy for the head-on collision of the particles is large if the difference between the metrics of the wormhole and the black hole is small. To deeply understand the high energy particle collision, we generalize the head-…
Structure at the horizon scale of black holes would give rise to echoes of the gravitational wave signal associated with the post-merger ringdown phase in binary coalescences. We study the waveform of echoes in static and stationary, traversable wormholes in which perturbations are governed by a symmetric effective potential. We argue that echoes are dominated by the wormhole quasinormal frequency nearest to the fundamental black hole frequency that controls the primary signal. We put forward an accurate method to construct the echoes waveform(s) from the primary signal and the quasinormal fre…
Bardeen's 1968 idea of a regular black hole spacetime was revived by Hayward in 2006 through the construction of a new example of such a geometry. Later it was realised by Neves and Saa, that a wider, two-parameter class exists, with Bardeen and Hayward spacetimes as special cases. In this article, we revisit and generalise the Hayward spacetime by applying the Damour-Solodukhin (DS) prescription. Recalling the DS suggestion of a deformed Schwarzschild spacetime where $g_{tt} = -\left (1-\frac{2M_1}{r}\right )$, $g_{rr} = \left (1-\frac{2M_2}{r}\right )^{-1}$ and $M_1\neq M_2$, we propose a si…
