568 research outputs found
Moduli-space structure of knots with intersections
It is well known that knots are countable in ordinary knot theory. Recently,
knots {\it with intersections} have raised a certain interest, and have been
found to have physical applications. We point out that such knots --equivalence
classes of loops in under diffeomorphisms-- are not countable; rather,
they exhibit a moduli-space structure. We characterize these spaces of moduli
and study their dimension. We derive a lower bound (which we conjecture being
actually attained) on the dimension of the (non-degenerate components) of the
moduli spaces, as a function of the valence of the intersection.Comment: 15 pages, latex-revtex, no figure
High-responsivity optical FET's fabricated on a FET-SEED structure
Optical detectors with responsivity of 1000 A/W and response time of 10 ÎŒs at 50 nW optical input power were fabricated using the AT&T FET-SEED process
GaAs optoelectronic neuron arrays
A simple optoelectronic circuit integrated monolithically in GaAs to implement sigmoidal neuron responses is presented. The circuit integrates a light-emitting diode with one or two transistors and one or two photodetectors. The design considerations for building arrays with densities of up to 10^4 cm^-2 are discussed
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