1,874 research outputs found
Harmonic analysis and the Riemann-Roch theorem
This paper is a continuation of papers: arXiv:0707.1766 [math.AG] and
arXiv:0912.1577 [math.AG]. Using the two-dimensional Poisson formulas from
these papers and two-dimensional adelic theory we obtain the Riemann-Roch
formula on a projective smooth algebraic surface over a finite field.Comment: 7 pages; to appear in Doklady Mathematic
Highly polarized injection luminescence in forward-biased ferromagnetic-semiconductor junctions at low spin polarization of current
We consider electron tunneling from a nonmagnetic -type semiconductor
(-S) into a ferromagnet (FM) through a very thin forward-biased Schottky
barrier resulting in efficient extraction of electron spin from a thin -S
layer near FM-S interface at low spin polarization of the current. We show that
this effect can be used for an efficient polarization radiation source in a
heterostructure where the accumulated spin polarized electrons are injected
from -S and recombine with holes in a quantum well. The radiation
polarization depends on a bias voltage applied to the FM-S junction.Comment: 4 pages, 2 figure
A class of spin injection-precession ultrafast nanodevices
Spin valve ultrafast spin injection devices are described: an amplifier, a
frequency multiplier, and a square-law detector. Their operation is based on
injection of spin polarized electrons from one ferromagnet to another through a
semiconductor layer and spin precession of the electrons in the semiconductor
layer in a magnetic field induced by a (base) current in an adjacent nanowire.
The base current can control the emitter current between the magnetic layers
with frequencies up to several 100 GHz.Comment: 4 pages, 2 figures; minor typos corrected; to appear in Appl. Phys.
Letter
The continuum gauge field-theory model for low-energy electronic states of icosahedral fullerenes
The low-energy electronic structure of icosahedral fullerenes is studied
within the field-theory model. In the field model, the pentagonal rings in the
fullerene are simulated by two kinds of gauge fields. The first one,
non-abelian field, follows from so-called K spin rotation invariance for the
spinor field while the second one describes the elastic flow due to pentagonal
apical disclinations. For fullerene molecule, these fluxes are taken into
account by introducing an effective field due to magnetic monopole placed at
the center of a sphere. Additionally, the spherical geometry of the fullerene
is incorporated via the spin connection term. The exact analytical solution of
the problem (both for the eigenfunctions and the energy spectrum) is found.Comment: 9 pages, 2 figures, submitted to European Physical Journal
Eight-quark interactions as a chiral thermometer
A NJL Lagrangian extended to six and eight quark interactions is applied to
study temperature effects (SU(3) flavor limit, massless case), and (realistic
massive case). The transition temperature can be considerably reduced as
compared to the standard approach, in accordance with recent lattice
calculations. The mesonic spectra built on the spontaneously broken vacuum
induced by the 't Hooft interaction strength, as opposed to the commonly
considered case driven by the four-quark coupling, undergoes a rapid crossover
to the unbroken phase, with a slope and at a temperature which is regulated by
the strength of the OZI violating eight-quark interactions. This strength can
be adjusted in consonance with the four-quark coupling and leaves the spectra
unchanged, except for the sigma meson mass, which decreases. A first order
transition behavior is also a possible solution within the present approach.Comment: 4 pages, 4 figures, prepared for the proceedings of Quark Matter 2008
- 20th International Conference on Ultra-Relativistic Nucleus Nucleus
Collisions, February 4-10, Jaipur (India
On some questions related to the Krichever correspondence
We investigate various new properties and examples of one-dimensional and
two-dimensional Krichever correspondence developed by Parshin. In particular,
we give explicit examples of the Krichever-Parshin map for various plane
curves, we introduce analogs of the Schur pairs in a two-dimensional local
field and show that they are oft geometrical. At the end we investigate analogs
of the KP hierarchy for two-dimensional local skew-fields with arbitrary
commutation law instead of the usual law of Weyl algebra. We derive for these
hierarchies new partial differential equations, which coincide with the usual
KP equation for certain values of parameters.Comment: 13
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