Spherical Orbifolds for Cosmic Topology

Harmonic analysis is a tool to infer cosmic topology from the measured astrophysical cosmic microwave background CMB radiation. For overall positive curvature, Platonic spherical manifolds are candidates for this analysis. We combine the specific point symmetry of the Platonic manifolds with their deck transformations. This analysis in topology leads from manifolds to orbifolds. We discuss the deck transformations of the orbifolds and give eigenmodes for the harmonic analysis as linear combinations of Wigner polynomials on the 3-sphere. These provide new tools for detecting cosmic topology from the CMB radiation.Comment: 17 pages, 9 figures. arXiv admin note: substantial text overlap with arXiv:1011.427

Pattern Formation from Defect Chaos --- A Theory of Chevrons

For over 25 years it is known that the roll structure of electroconvection (EC) in the dielectric regime in planarly aligned nematic liquid crystals has, after a transition to defect chaos, the tendency to form chevron structures. We show, with the help of a coarse-grained model, that this effect can generally be expected for systems with spontaneously broken isotropy, that is lifted by a small external perturbation. The linearized model as well as a nonlinear extension are compared to simulations of a system of coupled amplitude equations which generate chevrons out of defect chaos. The mechanism of chevron formation is similar to the development of Turing patterns in reaction diffusion systems.Comment: 17 pages, Latex, 11 PS-figures, submitted to Physica

Large-p_T Photoproduction of D^*+- Mesons in ep Collisions

The cross section for the inclusive photoproduction of large-p_T D^*+- mesons is calculated at next-to-leading order, adopting different approaches to describe the fragmentation of charm quarks into D^*+- mesons. We treat the charm quark according to the massless factorization scheme, where it is assumed to be one of the active flavours inside the proton and the photon. We present inclusive single-particle distributions in transverse momentum and rapidity, including the contributions due to both direct and resolved photons. We compare and assess the various implementations of fragmentation. We argue that, in the high-p_T regime, a particularly realistic description can be obtained by convoluting the Altarelli-Parisi-evolved fragmentation functions of Peterson et al. with the hard-scattering cross sections of massless partons where the factorization of the collinear singularities associated with final-state charm quarks is converted to the massive-charm scheme. The predictions thus obtained agree well with recent experimental data by the H1 and ZEUS Collaborations at DESY HERA.Comment: 31 pages (Latex), 13 figures (Postscript). This version of the manuscript is identical with the one being printed in Z. Phys.

Weakly Nonlinear Theory of Pattern-Forming Systems with Spontaneously Broken Isotropy

Quasi two-dimensional pattern forming systems with spontaneously broken isotropy represent a novel symmetry class, that is experimentally accessible in electroconvection of homeotropically aligned liquid crystals. We present a weakly nonlinear analysis leading to amplitude equations which couple the short-wavelength patterning mode with the Goldstone mode resulting from the broken isotropy. The new coefficients in these equations are calculated from the hydrodynamics. Simulations exhibit a new type of spatio-temporal chaos at onset. The results are compared with experiments.Comment: 4 pages, RevTeX, 4 PS-figures, to appear in PR

The New Sex Discrimination

Sex discrimination law has not kept pace with the lived experience of discrimination. In the early years of Title VII of the Civil Rights Act of 1964, courts settled on an idea of what sex discrimination looks like—formal practices that exclude employees based on their group membership. The problem is that sex discrimination has become highly individualized. Modern sex discrimination does not target all men or all women, nor does it target subgroups of men or women. The victims of modern sex discrimination are particular men and women who face discrimination because they do not or cannot conform to the norms of the workplace. These employees have been shut out of a sex discrimination regime that still expects employees to anchor their claims to a narrative of group subordination. I argue that the lived experience of discrimination should determine employment discrimination doctrine and not the other way around. Accordingly, I propose a new regime for sex discrimination law. The model for the new sex discrimination regime is religious discrimination law. Unlike other areas of employment discrimination law, religious discrimination law offers a dynamic conception of identity and a greater array of different theories of discrimination. I argue that sex discrimination law can and should work this way, too. On a broader level, the paper makes a strong normative claim about the substance of Title VII\u27s sex equality project. I argue that sex discrimination law needs to recalibrate its vision of equality. Difference is universal. No two women (or men) are the same, and this is a good thing. Thus the central task of sex discrimination law should be to better recognize—and, in turn, protect—the distinctive ways in which employees express their maleness and femaleness. It is these differences, after all, that shape the way employees experience modern sex discrimination