102,081 research outputs found
The energy of interaction between two hydrogen atoms by the Gaussian-type functions
Energy of interaction between two hydrogen atoms in their ground states described by Gauss-type function
Subwavelength localization and toroidal dipole moment of spoof surface plasmon polaritons
We experimentally and theoretically demonstrate subwavelength scale localization of spoof surface plasmon polaritons at a point defect in a two-dimensional groove metal array. An analytical expression for dispersion relation of spoof surface plasmon polaritons substantiates the existence of a band gap where a defect mode can be introduced. A waveguide coupling method allows us to excite localized spoof surface plasmon polariton modes and measure their resonance frequencies. Numerical calculations confirm that localized modes can have a very small modal volume and a high Q factor both of which are essential in enhancing light-matter interactions. Interestingly, we find that the localized spoof surface plasmon polariton has a significant toroidal dipole moment, which is responsible for the high Q factor, as well as an electric quadrupole moment. In addition, the dispersion properties of spoof surface plasmon polaritons are analyzed using a modal expansion method and numerical calculations
Effect of mass asymmetry on the mass dependence of balance energy
We demonstrate the role of the mass asymmetry on the balance energy (Ebal) by
studying asymmetric reactions throughout the periodic table and over entire
colliding geometry. Our results, which are almost independent of the system
size and as well as of the colliding geometries indicate a sizeable effect of
the asymmetry of the reaction on the balance energy.Comment: Journal of Physics - Conference Series - Online end of March (2011
A new concept for high-cycle-life LEO: Rechargeable MnO2-hydrogen
The nickel-hydrogen secondary battery system, developed in the early 1970s, has become the system of choice for geostationary earth orbit (GEO) applications. However, for low earth orbit (LEO) satellites with long expected lifetimes the nickel positive limits performance. This requires derating of the cell to achieve very long cycle life. A new system, rechargeable MnO2-Hydrogen, which does not require derating, is described here. For LEO applications, it promises to have longer cycle life, high rate capability, a higher effective energy density, and much lower self-discharge behavior than those of the nickel-hydrogen system
Energies of knot diagrams
We introduce and begin the study of new knot energies defined on knot
diagrams. Physically, they model the internal energy of thin metallic solid
tori squeezed between two parallel planes. Thus the knots considered can
perform the second and third Reidemeister moves, but not the first one. The
energy functionals considered are the sum of two terms, the uniformization term
(which tends to make the curvature of the knot uniform) and the resistance term
(which, in particular, forbids crossing changes). We define an infinite family
of uniformization functionals, depending on an arbitrary smooth function
and study the simplest nontrivial case , obtaining neat normal forms
(corresponding to minima of the functional) by making use of the Gauss
representation of immersed curves, of the phase space of the pendulum, and of
elliptic functions
Muonium-antimuonium conversion in models with heavy neutrinos
We study muonium-antimuonium conversion and mu+ e- to mu- e+ scattering
within two different lepton-flavor-violating models with heavy neutrinos: model
I is a typical seesaw that violates lepton number as well as flavor; model II
has a neutrino mass texture where lepton number is conserved. We look for the
largest possible amplitudes of these processes that are consistent with current
bounds. We find that model I has very limited chance of providing an observable
signal, except if a finely tuned condition in parameter space occurs. Model II,
on the other hand, requires no fine tuning and could cause larger effects.
However, the maximum amplitude provided by this model is still two orders of
magnitude below the sensitivity of current experiments: one predicts an
effective coupling G_MM up to 10^{-4}G_F for heavy neutrino masses near 10 TeV.
We have also clarified some discrepancies in previous literature on this
subject.Comment: 16 pages, 4 figures, reference adde
The Revival of the Unified Dark Energy-Dark Matter Model ?
We consider the generalized Chaplygin gas (GCG) proposal for unification of
dark energy and dark matter and show that it admits an unique decomposition
into dark energy and dark matter components once phantom-like dark energy is
excluded. Within this framework, we study structure formation and show that
difficulties associated to unphysical oscillations or blow-up in the matter
power spectrum can be circumvented. Furthermore, we show that the dominance of
dark energy is related to the time when energy density fluctuations start
deviating from the linear behaviour.Comment: 6 pages, 4 eps figures, Revtex4 style. New References are added. Some
typos are corrected. Conclusions remain the sam
A frictionless microswimmer
We investigate the self-locomotion of an elongated microswimmer by virtue of
the unidirectional tangential surface treadmilling. We show that the propulsion
could be almost frictionless, as the microswimmer is propelled forward with the
speed of the backward surface motion, i.e. it moves throughout an almost
quiescent fluid. We investigate this swimming technique using the special
spheroidal coordinates and also find an explicit closed-form optimal solution
for a two-dimensional treadmiler via complex-variable techniques.Comment: 6 pages, 4 figure
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