In this paper we prove a recent conjecture [Robnik M and Salasnich L 1997 J. Phys. A: Math. Gen. 3

M q ðxÞ 1⁄4 x T q ðxÞ x T q ðxÞ: (5) Since Jþi is a leading-twist operator, it is clear that such a simple partonic interpretation should exist. However, Ji, Xiong, and Yuan misleadingly interpret Jþi as the transverse angular momentum operator. Indeed, in light-front quantization, the role of time is taken by xþ, so that Jþi is the light-front transverse boost operator. In terms of the more co...

We introduce the angular-momentum flux as the natural description of the angular momentum carried by light. We present four main results: (i) angular-momentum flux is the flow of angular momentum across a surface and, in conjunction with the more familiar angular-momentum density, expresses the conservation of angular momentum. (ii) The angular-momentum flux for a light beam about its axis (or ...

a gyroscope is a device for measuring or maintaining orientation , based on the principles of conservation of angular momentum . the device is a spinning wheel or disk whose axle is free to take any orientation. this orientation changes much less in response to a given external torque than it would without the large angular momentum associated with the gyroscope's high rate of spin. since exter...

We demonstrate the Fourier relationship between angular position and angular momentum for a light mode. In particular we measure the distribution of orbital angular momentum states of light that has passed through an aperture and verify that the orbital angular momentum distribution is given by the complex Fourier-transform of the aperture function. We use spatial light modulators, configured a...

Noting that current chemical theory is based almost exclusively on electronic energy and spin variables the equal importance of orbital angular momentum is explored in this paper. From its classical definition the angular momentum of electrons in an atom is shown to obey Laplace’s equation, which automatically leads to discrete values in terms of spherical harmonics. This analysis assumes a con...

In condensed matter systems it is necessary to distinguish between the momentum of constituents system and pseudomomentum quasiparticles. The same distinction also valid for angular pseudoangular momentum. Based on Noether's theorem, we demonstrate that recently discussed orbital momenta phonons magnons are momenta. This conceptual difference important a proper understanding transfer in systems...