Lensing and imaging by a stealth defect of spacetime

A stealth defect of spacetime

We discuss a special type of Skyrmion spacetime-defect solution, which has a positive energy density of the matter fields but a vanishing asymptotic gravitational mass. With a mass term for the matter field added to the action (corresponding to massive "pions" in the Skyrme model), this particular soliton-type solution has no long-range fields and can appropriately be called a "stealth defect."

On a soliton-type spacetime defect

We review the construction of a particular soliton-type solution of the classical Einstein and matter-field equations. This localized finite-energy static classical solution can be interpreted as a single spacetime defect embedded in Minkowski spacetime and may give rise to several new effects. For a Skyrme-type theory with small enough matter-field energy scale compared to the Planck energy scale and for a sufficiently small defect length scale, the existence of a globally regular solution requires a negative active gravitational mass, so that the defect repels a distant test particle ("antig…

Gravitational lensing by Reissner-Nordström black holes with topological defects

Using a new geometrical approach introduced by Gibbons and Werner we study the deflection angle by Reissner-Nordström black holes in the background spacetimes with a global monopole and a cosmic string. By calculating the corresponding optical Gaussian curvature and applying the Gauss-Bonnet theorem to the optical metric we find the leading terms of the deflection angle in the weak limit approximation. We find that the deflection angle increases due to the presence of topological defects.

Singular lensing from the scattering on special space-time defects

It is well known that certain special classes of self-gravitating point-like defects, such as global (non gauged) monopoles, give rise to non-asymptotically flat space-times characterized by solid angle deficits, whose size depends on the details of the underlying microscopic models. The scattering of electrically neutral particles on such space-times is described by amplitudes that exhibit resonant behaviour when the scattering and deficit angles coincide. This, in turn, leads to ring-like structures where the cross sections are formally divergent ("singular lensing"). In this work, we revisi…

带拓扑缺陷的Schwarzschild-Klinkhamer虫洞周围试验粒子的测地线运动及引力透镜效应

Geodesics motion of test particles around Schwarzschild-Klinkhamer wormhole with topological defects and gravitational lensing

本研究分析带宇宙弦、整体单极子拓扑缺陷的Schwarzschild-Klinkhamer虫洞时空中试验粒子测地线运动与类光测地线偏转角，明确两类缺陷对有效势、偏转角的修正作用，并给出对应时空已知解。

Semiclassical gravitational effects on the gravitational lensing in the spacetime of topological defects

The theory of gravitational lensing has revealed many generic and fundamental properties of compact objects like black holes and wormholes. In this article, we utilize a recent formulation to compute the quantum effects on the deflection angle of a light ray, namely, the Gauss-Bonnet theorem (GBT) to explore the semiclassical gravitational effects in the spacetime of a point-like global monopole and a cosmic string. Previously, the Gauss-Bonnet theorem [Class. Quant. Grav. 25, 235009 (2008)] was proposed as an alternative way to compute the deflection angle of light in a static, spherically sy…