scholarly journals Special Issue on Novel Insights into Orbital Angular Momentum Beams: From Fundamentals, Devices to Applications

2019 ◽  
Vol 9 (13) ◽  
pp. 2600 ◽  
Author(s):  
Yang Yue ◽  
Hao Huang ◽  
Yongxiong Ren ◽  
Zhongqi Pan ◽  
Alan E. Willner
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Elementary Particles ◽  
Spin Angular Momentum ◽  
Special Issue

It is well-known now that angular momentum carried by elementary particles can be categorized as spin angular momentum (SAM) and orbital angular momentum (OAM) [...]

scholarly journals Proper relativistic position operators in 1+1 and 2+1 dimensions

2020 ◽  
Vol 35 (18) ◽  
pp. 2050084
Author(s):  
Taeseung Choi
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Wave Equations ◽  
Position Operator ◽  
Spin Angular Momentum ◽  
Particle Position ◽  
Constant Of Motion ◽  
Mass Moment ◽  
Relativistic Position ◽  
Canonical Position

We have revisited the Dirac theory in [Formula: see text] and [Formula: see text] dimensions by using the covariant representation of the parity-extended Poincaré group in their native dimensions. The parity operator plays a crucial role in deriving wave equations in both theories. We studied two position operators, a canonical one and a covariant one that becomes the particle position operator projected onto the particle subspace. In [Formula: see text] dimensions the particle position operator, not the canonical position operator, provides the conserved Lorentz generator. The mass moment defined by the canonical position operator needs an additional unphysical spin-like operator to become the conserved Lorentz generator in [Formula: see text] dimensions. In [Formula: see text] dimensions, the sum of the orbital angular momentum given by the canonical position operator and the spin angular momentum becomes a constant of motion. However, orbital and spin angular momentum do not conserve separately. On the other hand the orbital angular momentum given by the particle position operator and its corresponding spin angular momentum become a constant of motion separately.

Formation of the initial distribution of matter inhomogeneities in the era of radiation domination

2015 ◽  
Vol 12 (09) ◽  
pp. 1550097 ◽  
Author(s):  
Yuriy A. Portnov
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Initial Distribution ◽  
Elementary Particles ◽  
Expansion Rate ◽  
Material Inhomogeneity ◽  
Universe Expansion ◽  
Primary Material ◽  
The Future ◽  
The Universe

This paper considers the dependence of the Universe expansion rate in the era of radiation domination of the orbital angular momentum of photons filling the Universe. It is shown that the presence of a nonzero orbital angular momentum in photons leads to increase in the rate of expansion. As a consequence, the hypothesis is made that areas of the Universe, having photons with nonzero orbital angular momentum inside them, will cool faster. In these areas the elementary particles will form earlier, compared to the rest of the Universe. Therefore, these areas become the future centers of the primary material inhomogeneity.

scholarly journals From Majorana Neutrino and Dark Neutrino 0 to Dark Spin Particles

2021 ◽  
pp. 17-31
Author(s):  
ShaoXu Ren
Keyword(s):  
Angular Momentum ◽  
Particle Physics ◽  
Casimir Operator ◽  
Current Theory ◽  
Majorana Neutrino ◽  
Elementary Particles ◽  
Spin Angular Momentum

In current theory of particle physics, the values of Casimir Operator, that is abbreviated to CO, of spin angular momentum for elementary particles are thought to be greater than zero.

scholarly journals Spin angular momentum of proton spin puzzle in complex octonion spaces

2017 ◽  
Vol 14 (07) ◽  
pp. 1750102 ◽  
Author(s):  
Zi-Hua Weng
Keyword(s):  
Electromagnetic Field ◽  
Quantum Mechanics ◽  
Dipole Moment ◽  
Angular Momentum ◽  
Angular Velocity ◽  
Orbital Angular Momentum ◽  
Magnetic Dipole Moment ◽  
Proton Spin ◽  
Spin Angular Momentum ◽  
Precessional Motion

The paper focuses on considering some special precessional motions as the spin motions, separating the octonion angular momentum of a proton into six components, elucidating the proton angular momentum in the proton spin puzzle, especially the proton spin, decomposition, quarks and gluons, and polarization and so forth. Maxwell was the first to use the quaternions to study the electromagnetic fields. Subsequently the complex octonions are utilized to depict the electromagnetic field, gravitational field, and quantum mechanics and so forth. In the complex octonion space, the precessional equilibrium equation infers the angular velocity of precession. The external electromagnetic strength may induce a new precessional motion, generating a new term of angular momentum, even if the orbital angular momentum is zero. This new term of angular momentum can be regarded as the spin angular momentum, and its angular velocity of precession is different from the angular velocity of revolution. The study reveals that the angular momentum of the proton must be separated into more components than ever before. In the proton spin puzzle, the orbital angular momentum and magnetic dipole moment are independent of each other, and they should be measured and calculated respectively.

Arbitrary spin-to–orbital angular momentum conversion of light

Science ◽  
2017 ◽  
Vol 358 (6365) ◽  
pp. 896-901 ◽  
Author(s):  
Robert C. Devlin ◽  
Antonio Ambrosio ◽  
Noah A. Rubin ◽  
J. P. Balthasar Mueller ◽  
Federico Capasso
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Optical Communication ◽  
Arbitrary Spin ◽  
Spin States ◽  
Spin Angular Momentum ◽  
Optical Elements ◽  
Left And Right ◽  
General Material ◽  
Elliptically Polarized

Optical elements that convert the spin angular momentum (SAM) of light into vortex beams have found applications in classical and quantum optics. These elements—SAM-to–orbital angular momentum (OAM) converters—are based on the geometric phase and only permit the conversion of left- and right-circular polarizations (spin states) into states with opposite OAM. We present a method for converting arbitrary SAM states into total angular momentum states characterized by a superposition of independent OAM. We designed a metasurface that converts left- and right-circular polarizations into states with independent values of OAM and designed another device that performs this operation for elliptically polarized states. These results illustrate a general material-mediated connection between SAM and OAM of light and may find applications in producing complex structured light and in optical communication.

Spin Hall effect of light in inhomogeneous nonlinear medium

2016 ◽  
Vol 30 (02) ◽  
pp. 1550270
Author(s):  
Hehe Li ◽  
Xinzhong Li
Keyword(s):  
Angular Momentum ◽  
Hall Effect ◽  
Orbital Angular Momentum ◽  
Nonlinear Medium ◽  
Spin Hall Effect ◽  
Phase Front ◽  
Spin Angular Momentum ◽  
Linear Complex ◽  
Complex Valued ◽  
Effect Of Light

In this paper, we investigate the spin Hall effect of a polarized Gaussian beam (GB) in a smoothly inhomogeneous isotropic and nonlinear medium using the method of the eikonal-based complex geometrical optics which describes the phase front and cross-section of a light beam using the quadratic expansion of a complex-valued eikonal. The linear complex-valued eikonal terms are introduced to describe the polarization-dependent transverse shifts of the beam in inhomogeneous nonlinear medium which is called the spin Hall effect of beam. We know that the spin Hall effect of beam is affected by the nonlinearity of medium and include two parts, one originates from the coupling between the spin angular momentum and the extrinsic orbital angular momentum due to the curve trajectory of the center of gravity of the polarized GB and the other from the coupling between the spin angular momentum and the intrinsic orbital angular momentum due to the rotation of the beam with respect to the central ray.

Light beams with selective angular momentum generated by hybrid plasmonic waveguides

Nanoscale ◽  
2014 ◽  
Vol 6 (21) ◽  
pp. 12360-12365 ◽  
Author(s):  
Yao Liang ◽  
Han Wen Wu ◽  
Bin Jie Huang ◽  
Xu Guang Huang
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Silicon Photonics ◽  
Spin Angular Momentum ◽  
Plasmonic Waveguides ◽  
Hybrid Plasmonic Waveguides ◽  
Light Beams

We report an integrated compact technique that can “spin” and “twist” light on a silicon photonics platform, with the generated light beams possessing both spin angular momentum (SAM) and orbital angular momentum (OAM).

scholarly journals Optical angular momentum and atoms

2017 ◽  
Vol 375 (2087) ◽  
pp. 20150435 ◽  
Author(s):  
Sonja Franke-Arnold
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Cold Atoms ◽  
Spin Angular Momentum ◽  
Frequency Converters ◽  
Quantum Properties ◽  
Coherent Interaction ◽  
Fundamental Understanding ◽  
The Individual ◽  
Optical Angular Momentum

Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom’s angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light’s OAM, aiding our fundamental understanding of light–matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors. This article is part of the themed issue ‘Optical orbital angular momentum’.

scholarly journals Control of the Spin Angular Momentum and Orbital Angular Momentum of a Reflected Wave by Multifunctional Graphene Metasurfaces

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1054 ◽  
Author(s):  
Chen Zhang ◽  
Li Deng ◽  
Jianfeng Zhu ◽  
Weijun Hong ◽  
Ling Wang ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Spin Angular Momentum ◽  
Reflected Wave
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