scholarly journals Gravitational bending angle with finite distances by Casimir wormholes

2021 ◽  
Author(s):  
Í. D. D. Carvalho ◽  
G. Alencar ◽  
C. R. Muniz
Keyword(s):  
Uncertainty Principle ◽  
Deflection Angle ◽  
Generalized Uncertainty Principle ◽  
Casimir Energy ◽  
Type Ii ◽  
Bending Angle ◽  
Test Particles ◽  
Self Consistent ◽  
The Deflection Angle ◽  
Jacobi Metric

In this paper, we investigate the gravitational bending angle due to the Casimir wormholes, which consider the Casimir energy as the source. Furthermore, some of these Casimir wormholes regard Generalized Uncertainty Principle (GUP) corrections of Casimir energy. We use the Ishihara method for the Jacobi metric, which allows us to study the bending angle of light and massive test particles for finite distances. Beyond the uncorrected Casimir source, we consider many GUP corrections, namely, the Kempf, Mangano and Mann (KMM) model, the Detournay, Gabriel and Spindel (DGS) model, and the so-called type II model for the GUP principle. We also find the deflection angle of light and massive particles in the case of the receiver and the source are far away from the lens. In this case, we also compute the optical scalars: convergence and shear for these Casimir wormholes as a gravitational weak lens. Our self-consistent iterative calculations indicate corrections to the bending angle by Casimir wormholes in the previous paper.

scholarly journals Traversable wormholes supported by GUP corrected Casimir energy

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Kimet Jusufi ◽  
Phongpichit Channuie ◽  
Mubasher Jamil
Keyword(s):  
Deflection Angle ◽  
Equations Of State ◽  
Generalized Uncertainty Principle ◽  
Casimir Energy ◽  
Energy Conditions ◽  
Strong Condition ◽  
Asymptotically Flat ◽  
Wormhole Throat ◽  
Classical Energy ◽  
Traversable Wormholes

Abstract In this paper, we investigate the effect of the Generalized Uncertainty Principle (GUP) in the Casimir wormhole spacetime recently proposed by Garattini (Eur Phys J C 79: 951, 2019). In particular, we consider three types of GUP relations, firstly the Kempf, Mangano and Mann (KMM) model, secondly the Detournay, Gabriel and Spindel (DGS) model, and finally the so-called type II model for the GUP principle. To this end, we consider three specific models of the redshift function along with two different equations of state (EoS), given by $${\mathcal {P}}_r(r)=\omega _r(r) \rho (r)$$Pr(r)=ωr(r)ρ(r) and $${\mathcal {P}}_t(r)=\omega _t (r){\mathcal {P}}_r(r)$$Pt(r)=ωt(r)Pr(r) and obtain a class of asymptotically flat wormhole solutions supported by Casimir energy under the effect of GUP. Furthermore we check the null, weak, and strong condition at the wormhole throat with a radius $$r_0$$r0, and we show that in general the classical energy conditions are violated by some arbitrary quantity at the wormhole throat. Importantly, we examine the wormhole geometry with semiclassical corrections via embedding diagrams. We also consider the ADM mass of the wormhole, the volume-integral quantifier to calculate the amount of the exotic matter near the wormhole throat, and the deflection angle of light.

scholarly journals Deflection of light by a Coulomb charge in Born–Infeld electrodynamics

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
Jin Young Kim
Keyword(s):  
Black Hole ◽  
Electric Field ◽  
Deflection Angle ◽  
Strong Electric Field ◽  
Background Field ◽  
Geodesic Equation ◽  
Bending Angle ◽  
Propagation Of Light ◽  
The Deflection Angle ◽  
Trajectory Equation

AbstractWe study the propagation of light under a strong electric field in Born–Infeld electrodynamics. The nonlinear effect can be described by the effective indices of refraction. Because the effective indices of refraction depend on the background electric field, the path of light can be bent when the background field is non-uniform. We compute the bending angle of light by a Born–Infeld-type Coulomb charge in the weak lensing limit using the trajectory equation based on geometric optics. We also compute the deflection angle of light by the Einstein–Born–Infeld black hole using the geodesic equation and confirm that the contribution of the electric charge to the total bending angle agree.

scholarly journals Particle Motion and Plasma Effects on Gravitational Weak Lensing in Lorentzian Wormhole Spacetime

Galaxies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 54
Author(s):  
Farruh Atamurotov ◽  
Sanjar Shaymatov ◽  
Bobomurat Ahmedov
Keyword(s):  
Particle Motion ◽  
Deflection Angle ◽  
Weak Lensing ◽  
Test Particles ◽  
Stable Circular Orbit ◽  
Plasma Effects ◽  
Innermost Stable Circular Orbit ◽  
The Deflection Angle ◽  
Gravitational Weak Lensing ◽  
Uniform Plasma

Here we study particle motion in the specific Lorentzian wormhole spacetime characterized, in addition to the total mass M, with the dimensionless parameter λ. In particular we calculate the radius of the innermost stable circular orbit (ISCO) for test particles and the photonsphere for massless particles. We show that the effect of the dimensionless wormhole parameter decreases the ISCO radius and the radius of the photon orbit. Then, we study plasma effects on gravitational weak lensing in wormhole spacetime and obtain the deflection angle of the light. We show that the effect of λ decreases the deflection angle. We study the effects of uniform and non-uniform plasma on the light deflection angle separately, and show that the uniform plasma causes the deflection angle to be smaller in contrast to the non-uniform plasma.

scholarly journals The finite-distance gravitational deflection of massive particles in stationary spacetime: a Jacobi metric approach

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Zonghai Li ◽  
Junji Jia
Keyword(s):  
Black Hole ◽  
Deflection Angle ◽  
Kerr Black Hole ◽  
Relativistic Velocity ◽  
Massive Particles ◽  
Finite Distance ◽  
The Deflection Angle ◽  
Jacobi Metric ◽  
Optical Metric ◽  
Gravitational Deflection

Abstract In this paper, we study the weak gravitational deflection of relativistic massive particles for a receiver and source at finite distance from the lens in stationary, axisymmetric and asymptotically flat spacetimes. For this purpose, we extend the generalized optical metric method to the generalized Jacobi metric method by using the Jacobi–Maupertuis Randers–Finsler metric. More specifically, we apply the Gauss–Bonnet theorem to the generalized Jacobi metric space and then obtain an expression for calculating the deflection angle, which is related to Gaussian curvature of generalized optical metric and geodesic curvature of particles orbit. In particular, the finite-distance correction to the deflection angle of signal with general velocity in the the Kerr black hole and Teo wormhole spacetimes are considered. Our results cover the previous work of the deflection angle of light, as well as the deflection angle of massive particles in the limit for the receiver and source at infinite distance from the lens object. In Kerr black hole spacetime, we compared the effects due to the black hole spin, the finite-distance of source or receiver, and the relativistic velocity in microlensings and lensing by galaxies. It is found in these cases, the effect of black hole spin is usually a few orders larger than that of the finite-distance and relativistic velocity, while the relative size of the latter two could vary according to the particle velocity, source or observer distance and other lensing parameters.

scholarly journals Determination of bending angle of light deflection subject to possible weak and strong quantum gravity effects

2020 ◽  
Vol 35 (29) ◽  
pp. 2050188
Author(s):  
Chenmei Xu ◽  
Yisong Yang
Keyword(s):  
Differential Equation ◽  
Quantum Gravity ◽  
Deflection Angle ◽  
Gravity Effect ◽  
Light Deflection ◽  
Bending Angle ◽  
Quantum Gravity Effect ◽  
Gravity Effects ◽  
The Deflection Angle

Explicit expressions for the bending angle of light deflection arising from phenomenologically deformed black hole metrics, subject to possible weak and strong quantum gravity effects, respectively, are obtained, by a highly effective method. The accuracy and effectiveness of these expressions are then illustrated by numerically solving the differential equation governing the deflection angle directly in the weak quantum-gravity effect situation.

scholarly journals Nonlinear electrodynamics effects on the black hole shadow, deflection angle, quasinormal modes and greybody factors

2022 ◽  
Vol 2022 (01) ◽  
pp. 009
Author(s):  
M. Okyay ◽  
A. Övgün
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Deflection Angle ◽  
Magnetic Charge ◽  
Generalized Uncertainty Principle ◽  
Quasinormal Modes ◽  
Nonlinear Electrodynamics ◽  
Stable Region ◽  
Massless Scalar ◽  
The Deflection Angle

Abstract In this paper, we discuss the effects of nonlinear electrodynamics (NED) on non-rotating black holes, parametrized by the field coupling parameter β and magnetic charge parameter P in detail. Particularly, we survey a large range of observables and physical properties of the magnetically charged black hole, including the thermodynamic properties, observational appearance, quasinormal modes and absorption cross sections. Initially, we show that the NED black hole is always surrounded by an event horizon and any magnetic charge is permissible. We then show that the black hole gets colder with increasing charge. Investigating the heat capacity, we see that the black hole is thermally stable between points of phase transition. Introducing a generalized uncertainty principle (GUP) with a quantum gravity parameter λ extends the range of the stable region, but the effect on temperature is negligible. Then we compute the deflection angle at the weak field limit, by the Gauss-Bonnet theorem and the geodesic equation, and find that even at the first order, the magnetic charge has a contribution due to the “field mass” term. Small changes of the charge contributes greatly to the paths of null geodesics due to the P 2 dependence of the horizon radius. Using a ray-tracing code, we simulate the observational appearance of a NED black hole under different emission profiles, thin disk and spherical accretion. We find that the parameter P has a very strong effect on the observed shadow radius, in agreement with the deflection angle calculations. We finally consider quasinormal modes under massless scalar perturbations of the black hole and the greybody factor. We find that the charge introduces a slight difference in the fundamental frequency of the emitted waveform. We find that the greybody factor of the NED black hole is strongly steepened by the introduction of increasing charge. To present observational constrains, we show that the magnetic charge of the M87* black hole is between 0 ≤ P ≤ 0.024 in units of M, in agreement with the idea that real astrophysical black holes are mostly neutral. We also find that LIGO/VIRGO and LISA could detect NED black hole perturbations from BHs with masses between 5 M ☉ and 8.0 · 108 M ☉. We finally show that for black holes with masses detected with LIGO so far, charged NED black holes would deviate from Schwarzschild by 5∼10 Hz in their fundamental frequencies.

scholarly journals Deflection of light in equatorial plane due to Kerr-Taub-NUT body

2017 ◽  
pp. 23-32
Author(s):  
Sarani Chakraborty ◽  
A.K. Sen
Keyword(s):  
General Relativity ◽  
Equatorial Plane ◽  
Deflection Angle ◽  
Order Term ◽  
Null Geodesic ◽  
Noticeable Effect ◽  
Bending Angle ◽  
Fourth Order Term ◽  
Magnetic Mass ◽  
The Deflection Angle

According to General Relativity, there are factors like mass, rotation, charge and presence of Cosmological constant that can influence the path of light ray. Apart from these factors, many authors have also reported the influence of gravitomagnetism on the path of light ray. In this study we have discussed the effect of a rotating Kerr-Taub-NUT body where the strength of the gravitomagnetic monopole is represented by the NUT factor or magnetic mass. We use the null geodesic of photon method to obtain the deflection angle of light ray for a Kerr-Taub-NUT body in equatorial plane upto the fourth order term. Our study shows that the NUT factor has a noticeable effect on the path of the light ray. By considering the magnetism to be zero, the expression of bending angle gets reduced to the Kerr bending angle. However, we obtained a non-zero bending angle for a hypothetical massless, magnetic body.

scholarly journals Quantitative evaluation indexes of the spatial steering effect of directional perforation hydraulic fractures

2021 ◽  
pp. 014459872110102
Author(s):  
Lu Weiyong ◽  
He Changchun
Keyword(s):  
Quantitative Evaluation ◽  
Hydraulic Fracture ◽  
Deflection Angle ◽  
Hydraulic Fractures ◽  
Principal Stress Direction ◽  
Perforation Hole ◽  
Evaluation Indexes ◽  
Initiation Pressure ◽  
The Deflection Angle ◽  
Bending Fracture

To better evaluate the spatial steering effect of directional perforation hydraulic fractures, evaluation indexes for the spatial steering effect are first proposed in this paper. Then, these indexes are used to quantitatively evaluate existing physical experimental results. Finally, with the help of RFPA2D-Flow software, the influence of perforation length and azimuth on the spatial steering process of hydraulic fracture are quantitatively analysed using four evaluation indexes. It is shown by the results that the spatial deflection trajectory, deflection distance, deflection angle and initiation pressure of hydraulic fractures can be used as quantitative evaluation indexes for the spatial steering effect of hydraulic fractures. The deflection paths of directional perforation hydraulic fractures are basically the same. They all gradually deflect to the maximum horizontal principal stress direction from the perforation hole and finally represent a double-wing bending fracture. The deflection distance, deflection angle and initiation pressure of hydraulic fractures increase gradually with increasing perforation azimuth, and the sensitivity of the deflection angle to the perforation azimuth of hydraulic fractures also increases. With increasing perforation length, the deflection distance of hydraulic fractures increases gradually. However, the deflection angle and initiation pressure decrease gradually, as does the sensitivity.

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