6,872 research outputs found
Particle-wave duality: a dichotomy between symmetry and asymmetry
Symmetry plays a central role in many areas of modern physics. Here we show
that it also underpins the dual particle and wave nature of quantum systems. We
begin by noting that a classical point particle breaks translational symmetry
whereas a wave with uniform amplitude does not. This provides a basis for
associating particle nature with asymmetry and wave nature with symmetry. We
derive expressions for the maximum amount of classical information we can have
about the symmetry and asymmetry of a quantum system with respect to an
arbitrary group. We find that the sum of the information about the symmetry
(wave nature) and the asymmetry (particle nature) is bounded by log(D) where D
is the dimension of the Hilbert space. The combination of multiple systems is
shown to exhibit greater symmetry and thus more wavelike character. In
particular, a class of entangled systems is shown to be capable of exhibiting
wave-like symmetry as a whole while exhibiting particle-like asymmetry
internally. We also show that superdense coding can be viewed as being
essentially an interference phenomenon involving wave-like symmetry with
respect to the group of Pauli operators.Comment: 20 pages, 3 figure
Schur Q-functions and degeneracy locus formulas for morphisms with symmetries
We give closed-form formulas for the fundamental classes of degeneracy loci
associated with vector bundle maps given locally by (not necessary square)
matrices which are symmetric (resp. skew-symmetric) w.r.t. the main diagonal.
Our description uses essentially Schur Q-polynomials of a bundle, and is based
on a certain push-forward formula for these polynomials in a Grassmann bundle.Comment: 22 pages, AMSTEX, misprints corrected, exposition improved. to appear
in the Proceedings of Intersection Theory Conference in Bologna, "Progress in
Mathematics", Birkhause
Integral Grothendieck-Riemann-Roch theorem
We show that, in characteristic zero, the obvious integral version of the
Grothendieck-Riemann-Roch formula obtained by clearing the denominators of the
Todd and Chern characters is true (without having to divide the Chow groups by
their torsion subgroups). The proof introduces an alternative to Grothendieck's
strategy: we use resolution of singularities and the weak factorization theorem
for birational maps.Comment: 24 page
Ultralight amorphous silicon alloy photovoltaic modules for space applications
Ultralight and ultrathin, flexible, rollup monolithic PV modules have been developed consisting of multijunction, amorphous silicon alloys for either terrestrial or aerospace applications. The rate of progress in increasing conversion efficiency of stable multijunction and multigap PV cells indicates that arrays of these modules can be available for NASA's high power systems in the 1990's. Because of the extremely light module weight and the highly automated process of manufacture, the monolithic a-Si alloy arrays are expected to be strongly competitive with other systems for use in NASA's space station or in other large aerospace applications
Moduli Spaces of Lumps on Real Projective Space
Harmonic maps that minimize the Dirichlet energy in their homotopy classes are known as lumps. Lump solutions on real projective space are explicitly given by rational maps subject to a certain symmetry requirement. This has consequences for the behaviour of lumps and their symmetries. An interesting feature is that the moduli space of charge three lumps is a D2-symmetric 7-dimensional manifold of cohomogeneity one. In this paper, we discuss the charge three moduli spaces of lumps from two perspectives: discrete symmetries of lumps and the Riemann-Hurwitz formula. We then calculate the metric and find explicit formula for various geometric quantities. We also discuss the implications for lump decay
Inflectional loci of scrolls
Let be a scroll over a smooth curve and let
\L=\mathcal O_{\mathbb P^N}(1)|_X denote the hyperplane bundle. The special
geometry of implies that some sheaves related to the principal part bundles
of \L are locally free. The inflectional loci of can be expressed in
terms of these sheaves, leading to explicit formulas for the cohomology classes
of the loci. The formulas imply that the only uninflected scrolls are the
balanced rational normal scrolls.Comment: 9 pages, improved version. Accepted in Mathematische Zeitschrif
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