Related Experiment Video
Updated: Feb 17, 2026
12:14
The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry
Published on: August 12, 2013
22.5K
Weak Gravitational Lensing of Finite Beams
Pierre Fleury1, Julien Larena2, Jean-Philippe Uzan3
1Départment de Physique Théorique, Université de Genève, 24 quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
Physical Review Letters
|December 9, 2017
Summary
This study introduces a new formalism for weak gravitational lensing, moving beyond the infinitesimal light beam approximation. It resolves the Ricci-Weyl problem, showing convergence depends on enclosed matter and enhancing shear for finite beams, impacting lensing survey interpretations.
Area of Science:
- Astrophysics
- Cosmology
- Gravitational Lensing
Background:
- Standard weak gravitational lensing theory uses the infinitesimal light beam approximation.
- This approximation leads to the unphysical Ricci-Weyl problem, where lensing sources depend on matter distribution resolution.
Purpose of the Study:
- To develop a strong-lensing-inspired formalism for finite light beams.
- To address and resolve the Ricci-Weyl problem within gravitational lensing theory.
Main Methods:
- Proposed a new theoretical framework for analyzing gravitational lensing of finite beams.
- Applied this formalism to investigate the relationship between matter distribution and lensing effects.
Main Results:
- Demonstrated that convergence is determined by the matter enclosed within the beam, independent of its distribution.
- Showed that shear is systematically enhanced for finite beams.
- Established that the Kaiser-Squires relation between shear and convergence is violated.
Conclusions:
- The findings challenge the standard weak lensing approximation.
- The violation of the Kaiser-Squires relation has significant implications for interpreting weak-lensing survey data.
- A revised understanding of gravitational lensing is needed for finite beams.
Related Concept Videos
01:19Deflection of a Beam
758
Accurately determining beam deflection and slope under various loading conditions in structural engineering is crucial for ensuring safety and structural integrity. Singularity functions offer a streamlined approach to analyzing beams, especially when multiple loading functions complicate the bending moment equation.
Singularity functions, described in an earlier lesson, are powerful mathematical tools that represent discontinuities within a function commonly encountered in structural loading...
Singularity functions, described in an earlier lesson, are powerful mathematical tools that represent discontinuities within a function commonly encountered in structural loading...
758
01:10Detection of Black Holes
2.6K
Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
2.6K
01:14Gravitation Between Spherically Symmetric Masses
1.4K
The gravitational potential energy between two spherically symmetric bodies can be calculated from the masses and the distance between the bodies, assuming that the center of mass is concentrated at the respective centers of the bodies.
1.4K
01:16Focusing of Light in the Eye
6.4K
Light rays enter the eye through the cornea, a transparent dome-shaped tissue that is the eye's outermost layer. The cornea bends or refracts, light rays traveling to the pupil. The shape of the cornea determines how much of the light is bent and whether the image will be focused correctly on the retina at the back of the eye. Once the light has passed through both refraction layers, it converges into a single focal point onto a small area. This is where photoreceptors start transforming...
6.4K
01:17Space-Time Curvature and the General Theory of Relativity
4.6K
In 1905, Albert Einstein published his special theory of relativity. According to this theory, no matter in the universe can attain a speed greater than the speed of light in a vacuum, which thus serves as the speed limit of the universe.
This has been verified in many experiments. However, space and time are no longer absolute. Two observers moving relative to one another do not agree on the length of objects or the passage of time. The mechanics of objects based on Newton's laws of...
This has been verified in many experiments. However, space and time are no longer absolute. Two observers moving relative to one another do not agree on the length of objects or the passage of time. The mechanics of objects based on Newton's laws of...
4.6K
01:15Beams with Symmetric Loadings
437
The moment-area method is an analytical tool used in structural engineering to determine the slope and deflection of beams under various loads. Consider a cantilever with a concentrated load and moment at the free end. The first step is constructing a free-body diagram to calculate the reactions at the fixed end. Next, the bending moment diagram is plotted to visualize how the bending moment varies along the beam's length, focusing on points where the bending moment equals zero.
The M/EI...
The M/EI...
437