43,579 research outputs found
Effects of quantum deformation on the spin-1/2 Aharonov-Bohm problem
In this letter we study the Aharonov-Bohm problem for a spin-1/2 particle in
the quantum deformed framework generated by the -Poincar\'{e}-Hopf
algebra. We consider the nonrelativistic limit of the -deformed Dirac
equation and use the spin-dependent term to impose an upper bound on the
magnitude of the deformation parameter . By using the self-adjoint
extension approach, we examine the scattering and bound state scenarios. After
obtaining the scattering phase shift and the -matrix, the bound states
energies are obtained by analyzing the pole structure of the latter. Using a
recently developed general regularization prescription [Phys. Rev. D.
\textbf{85}, 041701(R) (2012)], the self-adjoint extension parameter is
determined in terms of the physics of the problem. For last, we analyze the
problem of helicity conservation.Comment: 12 pages, no figures, submitted for publicatio
Remarks on the Aharonov-Casher dynamics in a CPT-odd Lorentz-violating background
The Aharonov-Casher problem in the presence of a Lorentz-violating background
nonminimally coupled to a spinor and a gauge field is examined. Using an
approach based on the self-adjoint extension method, an expression for the
bound state energies is obtained in terms of the physics of the problem by
determining the self-adjoint extension parameter.Comment: Matches published versio
Spin dependent transport in organic light-emitting diodes
Electrically Detected Magnetic Resonance (EDMR) was used to study a series of
multilayer organic devices based on aluminum (III) 8-hydroxyquinoline. These
devices were designed to identify the micoscopic origin of different spin
dependent process, i.e. hopping and exciton formation. EDMR is demonstrated to
probe molecular orbitals of charge, and thus indirectly explore interfaces,
exciton formation, charge accumalation and electric fields in operating organic
based devices
The fully kinetic Biermann battery and associated generation of pressure anisotropy
The dynamical evolution of a fully kinetic, collisionless system with imposed
background density and temperature gradients is investigated analytically. The
temperature gradient leads to the generation of temperature anisotropy, with
the temperature along the gradient becoming larger than that in the direction
perpendicular to it. This causes the system to become unstable to pressure
anisotropy driven instabilities, dominantly to electron Weibel. When both
density and temperature gradients are present and non-parallel to each other,
we obtain a Biermann-like linear in time magnetic field growth. Accompanying
particle in cell numerical simulations are shown to confirm our analytical
results.Comment: 5 pages, 2 figures, + Supplementary materials (4 pages, 2 figures
Even harmonic generation in isotropic media of dissociating homonuclear molecules
Isotropic gases irradiated by long pulses of intense IR light can generate
very high harmonics of the incident field. It is generally accepted that, due
to the symmetry of the generating medium, be it an atomic or an isotropic
molecular gas, only odd harmonics of the driving field can be produced. Here we
show how the interplay of electronic and nuclear dynamics can lead to a marked
breakdown of this standard picture: a substantial part of the harmonic spectrum
can consist of even rather than odd harmonics. We demonstrate the effect using
ab-initio solutions of the time-dependent Schr\"odinger equation for
and its isotopes in full dimensionality. By means of a simple
analytical model, we identify its physical origin, which is the appearance of a
permanent dipole moment in dissociating homonuclear molecules, caused by
light-induced localization of the electric charge during dissociation. The
effect arises for sufficiently long laser pulses and the region of the spectrum
where even harmonics are produced is controlled by pulse duration. Our results
(i) show how the interplay of femtosecond nuclear and attosecond electronic
dynamics, which affects the charge flow inside the dissociating molecule, is
reflected in the nonlinear response, and (ii) force one to augment standard
selection rules found in nonlinear optics textbooks by considering
light-induced modifications of the medium during the generation process.Comment: 7 pages, 6 figure
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