24,708 research outputs found
Point-source detection system rejects spatially extended radiation sources
System employing digital space correlation to suppress false target signals in a point-target tracking device is a reliable method for discriminating a distant target from false targets in the field of view of an infrared detection system or tracking device
Comment on "Perfect imaging with positive refraction in three dimensions"
Leonhard and Philbin [Phys. Rev. A 81, 011804(R) (2010)] have recently
constructed a mathematical proof that the Maxwell's fish-eye lens provides
perfect imaging of electromagnetic waves without negative refraction. In this
comment, we argue that the unlimited resolution is an artifact of having
introduced an unphysical drain at the position of the geometrical image. The
correct solution gives focusing consistent with the standard diffraction limit
Polymers for spacecraft hardware - Materials characterization, part I Interim report, Mar. - Dec. 1966
Environmental testing of polymeric materials for spacecraft hardwar
Global Classical Solutions of the Boltzmann Equation with Long-Range Interactions and Soft Potentials
In this work we prove global stability for the Boltzmann equation (1872) with
the physical collision kernels derived by Maxwell in 1866 for the full range of
inverse power intermolecular potentials, with . This
completes the work which we began in (arXiv:0912.0888v1). We more generally
cover collision kernels with parameters and satisfying
in arbitrary dimensions
with . Moreover, we prove rapid convergence as predicted by the
Boltzmann H-Theorem. When , we have exponential time decay
to the Maxwellian equilibrium states. When , our solutions
decay polynomially fast in time with any rate. These results are constructive.
Additionally, we prove sharp constructive upper and lower bounds for the
linearized collision operator in terms of a geometric fractional Sobolev norm;
we thus observe that a spectral gap exists only when , as
conjectured in Mouhot-Strain (2007).Comment: This file has not changed, but this work has been combined with
(arXiv:0912.0888v1), simplified and extended into a new preprint, please see
the updated version: arXiv:1011.5441v
Numerical study of the relativistic three-body quantization condition in the isotropic approximation
We present numerical results showing how our recently proposed relativistic
three-particle quantization condition can be used in practice. Using the
isotropic (generalized -wave) approximation, and keeping only the leading
terms in the effective range expansion, we show how the quantization condition
can be solved numerically in a straightforward manner. In addition, we show how
the integral equations that relate the intermediate three-particle
infinite-volume scattering quantity, , to the
physical scattering amplitude can be solved at and below threshold. We test our
methods by reproducing known analytic results for the expansion of the
threshold state, the volume dependence of three-particle bound-state energies,
and the Bethe-Salpeter wavefunctions for these bound states. We also find that
certain values of lead to unphysical finite-volume
energies, and give a preliminary analysis of these artifacts.Comment: 32 pages, 21 figures, JLAB-THY-18-2657, CERN-TH-2018-046; version 2:
corrected typos, updated references, minor stylistic changes---consistent
with published versio
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