Spin current, a flow of spins, is a key concept in the field of spintronics. It is generated by using angular momentum conversion among magnetic angular momentum due to magnetization dynamics, photon angular momentum, angular momentum due to orbital motion of electron, and spin angular momentum [1–3]. Meanwhile, mechanical angular momentum carried by condensed matter systems due to macroscopic ...

In recent yeam much aaention has been paid to the quantized evolution of the centreof-mass momentum and position of ultracold atoms in light fields. We consider the effects resulting from the quantization of the extemal angular momentum variables. We investigate how spin and orbital angular momentum of light are transferred to internal and extemal angular momenhlm of an atom in dipole and quadr...

All beams are a superposition of plane waves, which carry linear momentum in the direction of propagation with no net azimuthal component. However, plane waves incident on a hologram can produce a vortex beam carrying orbital angular momentum that seems to require an azimuthal linear momentum, which presents a paradox. We resolve this by showing that the azimuthal momentum is not a true linear ...

Massive binary black holes (BBHs) are inevitably formed in the merged galactic nuclei before the black holes finally merge by emitting the gravitational radiation. However, it is still unknown how a massive BBH evolves after its semi-major axis reached to the sub-parsec/parsec scale where the dynamical friction with the neighboring stars is ineffective (the so-called the final parsec problem). ...

Electron beams with helical wavefronts carrying orbital angular momentum are expected to provide new capabilities for electron microscopy and other applications. We used nanofabricated diffraction holograms in an electron microscope to produce multiple electron vortex beams with well-defined topological charge. Beams carrying quantized amounts of orbital angular momentum (up to 100ħ) per electr...

Photons propagating in Laguerre-Gaussian modes have characteristic orbital angular momenta, which are fundamental optical degrees of freedom. The orbital angular momentum of light has potential application in high-capacity optical communication and even in quantum information processing. In this work, we experimentally construct a ring cavity with four lenses and four mirrors that is completely...

We have developed a mode transformer comprising two custom refractive optical elements which convert orbital angular momentum states into transverse momentum states. This transformation allows for an efficient measurement of the orbital angular momentum content of an input light beam. We characterise the channel capacity of the system for 50 input modes, giving a maximum value of 3.46 bits per ...

The desire to push recent experiments on electron vortices to higher energies leads to some theoretical difficulties. In particular the simple and very successful picture of phase vortices of vortex charge ℓ associated with ℓℏ units of orbital angular momentum per electron is challenged by the facts that (i) the spin and orbital angular momentum are not separately conserved for a Dirac electron...

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...

We present an in-depth analysis of the resonant intermixing between optical orbital and spin angular momentum of Laguerre-Gaussian (LG) beams, mediated by chiral clusters made of silicon nanospheres. In particular, we establish a relationship between the spin and orbital quantum numbers characterizing the LG beam and the order q of the rotation symmetry group 𝒞q of the cluster of nanospheres fo...