79 research outputs found
Homogenization of resonant chiral metamaterials
Homogenization of metamaterials is a crucial issue as it allows to describe
their optical response in terms of effective wave parameters as e.g.
propagation constants. In this paper we consider the possible homogenization of
chiral metamaterials. We show that for meta-atoms of a certain size a critical
density exists above which increasing coupling between neighboring meta-atoms
prevails a reasonable homogenization. On the contrary, a dilution in excess
will induce features reminiscent to photonic crystals likewise prevailing a
homogenization. Based on Bloch mode dispersion we introduce an analytical
criterion for performing the homogenization and a tool to predict the
homogenization limit. We show that strong coupling between meta-atoms of chiral
metamaterials may prevent their homogenization at all.Comment: 8 pages, 7 figure
Status of the QCDSP project
We describe the completed 8,192-node, 0.4Tflops machine at Columbia as well
as the 12,288-node, 0.6Tflops machine assembled at the RIKEN Brookhaven
Research Center. Present performance as well as our experience in commissioning
these large machines is presented. We outline our on-going physics program and
explain how the configuration of the machine is varied to support a wide range
of lattice QCD problems, requiring a variety of machine sizes. Finally a brief
discussion is given of future prospects for large-scale lattice QCD machines.Comment: LATTICE98(machines), 3 pages, 1 picture, 1 figur
Muon Spin Relaxation Studies of Magnetic-Field-Induced Effects in High- Superconductors
Muon spin relaxation (SR) measurements in high transverse magnetic
fields () revealed strong field-induced quasi-static
magnetism in the underdoped and Eu doped (La,Sr)CuO and
LaBaCuO, existing well above and . The
susceptibility-counterpart of Cu spin polarization, derived from the muon spin
relaxation rate, exhibits a divergent behavior towards K. No
field-induced magnetism was detected in overdoped
LaSrCuO, optimally doped Bi2212, and Zn-doped
YBaCuO.Comment: 4 pages, 4 color figure
Metamaterial Polarization Converter Analysis: Limits of Performance
In this paper we analyze the theoretical limits of a metamaterial converter
that allows for linear-to- elliptical polarization transformation with any
desired ellipticity and ellipse orientation. We employ the transmission line
approach providing a needed level of the design generalization. Our analysis
reveals that the maximal conversion efficiency for transmission through a
single metamaterial layer is 50%, while the realistic re ection configuration
can give the conversion efficiency up to 90%. We show that a double layer
transmission converter and a single layer with a ground plane can have 100%
polarization conversion efficiency. We tested our conclusions numerically
reaching the designated limits of efficiency using a simple metamaterial
design. Our general analysis provides useful guidelines for the metamaterial
polarization converter design for virtually any frequency range of the
electromagnetic waves.Comment: 10 pages, 11 figures, 2 table
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