Scar Intensity Statistics in the Position Representation

We obtain general predictions for the distribution of wave function intensities in position space on the periodic orbits of chaotic ballistic systems. The expressions depend on effective system size N, instability exponent lambda of the periodic orbit, and proximity to a focal point of the orbit. Limiting expressions are obtained that include the asymptotic probability distribution of rare high-intensity events and a perturbative formula valid in the limit of weak scarring. For finite system sizes, a single scaling variable lambda N describes deviations from the semiclassical N -> infinity limit.Comment: To appear in Phys. Rev. E, 10 pages, including 4 figure

Authoring Prior Art

Patent law and copyright law are widely understood to diverge in how they approach prior art, the universe of information that already existed before a particular innovation’s development. For patents, prior art is paramount. An invention can’t be patented unless it is both novel and nonobvious when viewed against the backdrop of all the earlier inventions that paved the way. But for copyrights, prior art is supposed to be virtually irrelevant. Black-letter copyright doctrine doesn’t care if a creative work happens to resemble its predecessors, only that it isn’t actually copied from them. In principle, then, outside of the narrow question of whether someone might have drawn from a preexisting third-party source, copyright infringement disputes would seem to have little doctrinal use for prior art.But that principle turns out to be missing a big part of what’s actually going on in copyright litigation today. In this Article, we identify a surprising trend: parties in cases involving music are increasingly discussing anticipatory earlier works, and judges are increasingly holding it against them if they don’t. The concept of prior art, once for inventors only, is now for authors, too.A major cause for this change, we argue, is the influence of a small cadre of expert witnesses. We interviewed several of the most active experts in music copyright disputes, and we analyzed dozens of reports that they have filed over the last two decades. Our data revealed a group that has been focused on authorial prior art since well before the courts were. These experts’ professional self-understanding, moreover, diverges sharply from the traditionally limited role that experts are supposed to play in evaluating copyright infringement. They view prior art research as a major part of their job. And for many of them, that research is important not just because it can sift between copying and independent creation, but also because it informs their normative view of what expression deserves legal exclusivity in the first place. Because of this expert community, prior art isn’t just for patents anymore

Spin Diffusion in Double-Exchange Manganites

The theoretical study of spin diffusion in double-exchange magnets by means of dynamical mean-field theory is presented. We demonstrate that the spin-diffusion coefficient becomes independent of the Hund's coupling JH in the range of parameters JH*S >> W >> T, W being the bandwidth, relevant to colossal magnetoresistive manganites in the metallic part of their phase diagram. Our study reveals a close correspondence as well as some counterintuitive differences between the results on Bethe and hypercubic lattices. Our results are in accord with neutron scattering data and with previous theoretical work for high temperatures.Comment: 4.0 pages, 3 figures, RevTeX 4, replaced with the published versio

New direction for gamma-rays

The origin of energetic gamma-ray bursts is still unknown. But the detection of polarization of gamma-rays provides fresh insight into the mechanism driving these powerful explosions.Comment: Nature "News & Views", RE Coburn & Boggs (astro-ph/0305377

A numerical and symbolical approximation of the Nonlinear Anderson Model

A modified perturbation theory in the strength of the nonlinear term is used to solve the Nonlinear Schroedinger Equation with a random potential. It is demonstrated that in some cases it is more efficient than other methods. Moreover we obtain error estimates. This approach can be useful for the solution of other nonlinear differential equations of physical relevance.Comment: 21 pages and 7 figure

Time-independent approximations for periodically driven systems with friction

The classical dynamics of a particle that is driven by a rapidly oscillating potential (with frequency $\omega$) is studied. The motion is separated into a slow part and a fast part that oscillates around the slow part. The motion of the slow part is found to be described by a time-independent equation that is derived as an expansion in orders of $\omega^{-1}$ (in this paper terms to the order $\omega^{-3}$ are calculated explicitly). This time-independent equation is used to calculate the attracting fixed points and their basins of attraction. The results are found to be in excellent agreement with numerical solutions of the original time-dependent problem.Comment: 5 pages, 4 figures. Revised version. Minor change

Deterministic Weak Localization in Periodic Structures

The weak localization is found for perfect periodic structures exhibiting deterministic classical diffusion. In particular, the velocity autocorrelation function develops a universal quantum power law decay at 4 times Ehrenfest time, following the classical stretched-exponential type decay. Such deterministic weak localization is robust against weak enough randomness (e.g., quantum impurities). In the 1D and 2D cases, we argue that at the quantum limit states localized in the Bravis cell are turned into Bloch states by quantum tunnelling.Comment: 5 pages, 2 figure

Lysosomal enzyme precursors in coated vesicles derived from the exocytic and endocytic pathways.

The molecular forms of two lysosomal enzymes, cathepsin C and cathepsin D, have been examined in lysosomes and coated vesicles (CVs) of rat liver. In addition, the relative proportion of these lysosomal enzymes residing in functionally distinct CV subpopulations was quantitated. CVs contained newly synthesized precursor forms of the enzymes in contrast to lysosomes where only the mature forms were detected. Exocytic and endocytic CV subpopulations were prepared by two completely different protocols. One procedure, a density shift method, uses cholinesterase to alter the density of CVs derived from exocytic or endocytic pathways. The other relies on electrophoretic heterogeneity to accomplish the CV subfractionation. Subpopulations of CVs prepared by either procedure showed similar results, when examined for their relative proportion of cathepsin C and cathepsin D precursors. Within the starting CV preparation, exocytic CVs contained approximately 80-90% of the total steady-state levels of these enzymes while the level in the endocytic population was approximately 10-13%. The implications of these findings are discussed with regard to lysosome trafficking

Arnol'd Tongues and Quantum Accelerator Modes

The stable periodic orbits of an area-preserving map on the 2-torus, which is formally a variant of the Standard Map, have been shown to explain the quantum accelerator modes that were discovered in experiments with laser-cooled atoms. We show that their parametric dependence exhibits Arnol'd-like tongues and perform a perturbative analysis of such structures. We thus explain the arithmetical organisation of the accelerator modes and discuss experimental implications thereof.Comment: 20 pages, 6 encapsulated postscript figure

The Role of Muslim Devotional Practices in the Reversal of Language Shift

Fishman’s 1991 scale for evaluating language vitality proposes a stage in language shift where exclusively the older generation takes part in ‘rituals’, ‘concerts’ and ‘songfests’ in the minority language. Once this generation dies away, according to the scale, these cultural practices disappear with them. Within certain Muslim youth communities in the UK counter examples exist where the younger generation leads the way in reviving, performing and extending the repertoire of this religio-cultural heritage. Although this emerging expanded repertoire of song and poetry is clearly multilingual in nature, recitation and performance of the community heritage languages, Urdu and Punjabi, feature strongly. What remains to discover is whether such increasing familiarity with poetic language and form can impact positively on reversing the language shift these communities are experiencing in their third and fourth generations. Although there is evidence (Ostler & Lintinger 2015) that singing and reciting in other minority language settings, secular and religious, are not infrequent pursuits of youth, it is argued in this article that an accompanying religious revival provides an important extra, galvanising, boost to the process of possible reversing language shift. It is suggested that available scales for evaluating language vitality are inadequate in the face of complex diasporic minority language settings