457 research outputs found
Self-Consistent Model of Magnetospheric Electric Field, Ring Current, Plasmasphere, and Electromagnetic Ion Cyclotron Waves: Initial Results
Further development of our self-consistent model of interacting ring current (RC) ions and electromagnetic ion cyclotron (EMIC) waves is presented. This model incorporates large scale magnetosphere-ionosphere coupling and treats self-consistently not only EMIC waves and RC ions, but also the magnetospheric electric field, RC, and plasmasphere. Initial simulations indicate that the region beyond geostationary orbit should be included in the simulation of the magnetosphere-ionosphere coupling. Additionally, a self-consistent description, based on first principles, of the ionospheric conductance is required. These initial simulations further show that in order to model the EMIC wave distribution and wave spectral properties accurately, the plasmasphere should also be simulated self-consistently, since its fine structure requires as much care as that of the RC. Finally, an effect of the finite time needed to reestablish a new potential pattern throughout the ionosphere and to communicate between the ionosphere and the equatorial magnetosphere cannot be ignored
Global, collisional model of high‐energy photoelectrons
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95539/1/grl8976.pd
Anisotropic diffusion in continuum relaxation of stepped crystal surfaces
We study the continuum limit in 2+1 dimensions of nanoscale anisotropic
diffusion processes on crystal surfaces relaxing to become flat below
roughening. Our main result is a continuum law for the surface flux in terms of
a new continuum-scale tensor mobility. The starting point is the Burton,
Cabrera and Frank (BCF) theory, which offers a discrete scheme for atomic steps
whose motion drives surface evolution. Our derivation is based on the
separation of local space variables into fast and slow. The model includes: (i)
anisotropic diffusion of adsorbed atoms (adatoms) on terraces separating steps;
(ii) diffusion of atoms along step edges; and (iii) attachment-detachment of
atoms at step edges. We derive a parabolic fourth-order, fully nonlinear
partial differential equation (PDE) for the continuum surface height profile.
An ingredient of this PDE is the surface mobility for the adatom flux, which is
a nontrivial extension of the tensor mobility for isotropic terrace diffusion
derived previously by Margetis and Kohn. Approximate, separable solutions of
the PDE are discussed.Comment: 14 pages, 1 figur
Quantum geometry of 3-dimensional lattices
We study geometric consistency relations between angles on 3-dimensional (3D)
circular quadrilateral lattices -- lattices whose faces are planar
quadrilaterals inscribable into a circle. We show that these relations generate
canonical transformations of a remarkable ``ultra-local'' Poisson bracket
algebra defined on discrete 2D surfaces consisting of circular quadrilaterals.
Quantization of this structure leads to new solutions of the tetrahedron
equation (the 3D analog of the Yang-Baxter equation). These solutions generate
an infinite number of non-trivial solutions of the Yang-Baxter equation and
also define integrable 3D models of statistical mechanics and quantum field
theory. The latter can be thought of as describing quantum fluctuations of
lattice geometry. The classical geometry of the 3D circular lattices arises as
a stationary configuration giving the leading contribution to the partition
function in the quasi-classical limit.Comment: 27 pages, 10 figures. Minor corrections, references adde
A bounce‐averaged kinetic model of the ring current ion population
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94668/1/grl7966.pd
Ground State Hyperfine Structure of Muonic Helium Atom
On the basis of the perturbation theory in the fine structure constant
and the ratio of the electron to muon masses we calculate one-loop
vacuum polarization and electron vertex corrections and the nuclear structure
corrections to the hyperfine splitting of the ground state of muonic helium
atom . We obtain total result for the ground state hyperfine
splitting MHz which improves the previous
calculation of Lakdawala and Mohr due to the account of new corrections. The
remaining difference between the theoretical result and experimental value of
the hyperfine splitting equal to 0.522 MHz lies in the range of theoretical
error and requires the subsequent investigation of higher order corrections.Comment: Talk presented at the scientific session-conference of Nuclear
Physics Department RAS "Physics of fundamental interactions", 25-30 November
2007, ITEP, Moscow, 18 pages, 5 figure
MSSM Baryogenesis and Electric Dipole Moments: An Update on the Phenomenology
We explore the implications of electroweak baryogenesis for future searches
for permanent electric dipole moments in the context of the minimal
supersymmetric extension of the Standard Model (MSSM). From a cosmological
standpoint, we point out that regions of parameter space that over-produce
relic lightest supersymmetric particles can be salvaged only by assuming a
dilution of the particle relic density that makes it compatible with the dark
matter density: this dilution must occur after dark matter freeze-out, which
ordinarily takes place after electroweak baryogenesis, implying the same degree
of dilution for the generated baryon number density as well. We expand on
previous studies on the viable MSSM regions for baryogenesis, exploring for the
first time an orthogonal slice of the relevant parameter space, namely the
(tan\beta, m_A) plane, and the case of non-universal relative gaugino-higgsino
CP violating phases. The main result of our study is that in all cases lower
limits on the size of the electric dipole moments exist, and are typically on
the same order, or above, the expected sensitivity of the next generation of
experimental searches, implying that MSSM electroweak baryogenesis will be soon
conclusively tested.Comment: 23 pages, 10 figures, matches version published in JHE
Specific features of the luminescence and conductivity of zinc selenide on exposure to X-ray and optical excitation
The set of experimental data on the X-ray-excited luminescence and X-ray
induced conductivity of ZnSe are compared to the data on the photoluminescence
and photoconductivity. It is experimentally established that the
current-voltage characteristics and the kinetics of phosphorescence and current
relaxation depend on the type of excitation. It is found that the external
electric field influences the intensity and shape of bands in the luminescence
spectra. It is shown that the character of excitation defines the kinetics of
recombination, charge carrier trapping, and conductivity in wide-gap
semiconductors.Comment: 7 pages, 7 figures, published in Fizika i Tekhnika Poluprovodnikov,
2010, Vol. 44, No. 5, pp. 594-59
Quantum Cryptography Based on the Time--Energy Uncertainty Relation
A new cryptosystem based on the fundamental time--energy uncertainty relation
is proposed. Such a cryptosystem can be implemented with both correlated photon
pairs and single photon states.Comment: 5 pages, LaTex, no figure
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