7,192 research outputs found
Electron beams of cylindrically symmetric spin polarization
Cylindrically symmetric electron beams in spin polarization are reported for
the first time. They are shown to be the eigen states of total angular momentum
in the direction. But they are neither the eigen states of spin nor the
eigen states of orbital angular momentum in that direction.Comment: 10 pages and 2 figure
A Non-Mainstream Viewpoint on Apparent Superluminal Phenomena in AGN Jet
The group velocity of light in material around the AGN jet is acquiescently
one (c as a unit), but this is only a hypothesis. Here, we re-derive apparent
superluminal and Doppler formulas for the general case (it is assumed that the
group velocity of light in the uniform and isotropic medium around a jet (a
beaming model) is not necessarily equal to one, e.g., Araudo et al. (2010)
thought that there may be dense clouds around AGN jet base), and show that the
group velocity of light close to one could seriously affect apparent
superluminal phenomena and Doppler effect in the AGN jet (when the viewing
angle and Lorentz factor take some appropriate values).Comment: 4 pages, 2 figures, new version accepted for publication in Journal
of Astrophysics and Astronom
Controllable Goos-H\"{a}nchen shifts and spin beam splitter for ballistic electrons in a parabolic quantum well under a uniform magnetic field
The quantum Goos-H\"{a}nchen shift for ballistic electrons is investigated in
a parabolic potential well under a uniform vertical magnetic field. It is found
that the Goos-H\"{a}nchen shift can be negative as well as positive, and
becomes zero at transmission resonances. The beam shift depends not only on the
incident energy and incidence angle, but also on the magnetic field and Landau
quantum number. Based on these phenomena, we propose an alternative way to
realize the spin beam splitter in the proposed spintronic device, which can
completely separate spin-up and spin-down electron beams by negative and
positive Goos-H\"{a}nchen shifts.Comment: 6 pages, 6 figure
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