Chabauty-Coleman experiments for genus 3 hyperelliptic curves

We describe a computation of rational points on genus 3 hyperelliptic curves $C$ defined over $\mathbb{Q}$ whose Jacobians have Mordell-Weil rank 1. Using the method of Chabauty and Coleman, we present and implement an algorithm in Sage to compute the zero locus of two Coleman integrals and analyze the finite set of points cut out by the vanishing of these integrals. We run the algorithm on approximately 17,000 curves from a forthcoming database of genus 3 hyperelliptic curves and discuss some interesting examples where the zero set includes global points not found in $C(\mathbb{Q})$.Comment: 18 page

Phantom energy traversable wormholes

It has been suggested that a possible candidate for the present accelerated expansion of the Universe is ''phantom energy''. The latter possesses an equation of state of the form $\omega\equiv p/\rho<-1$, consequently violating the null energy condition. As this is the fundamental ingredient to sustain traversable wormholes, this cosmic fluid presents us with a natural scenario for the existence of these exotic geometries. Due to the fact of the accelerating Universe, macroscopic wormholes could naturally be grown from the submicroscopic constructions that originally pervaded the quantum foam. One could also imagine an advanced civilization mining the cosmic fluid for phantom energy necessary to construct and sustain a traversable wormhole. In this context, we investigate the physical properties and characteristics of traversable wormholes constructed using the equation of state $p=\omega \rho$, with $\omega<-1$. We analyze specific wormhole geometries, considering asymptotically flat spacetimes and imposing an isotropic pressure. We also construct a thin shell around the interior wormhole solution, by imposing the phantom energy equation of state on the surface stresses. Using the ''volume integral quantifier'' we verify that it is theoretically possible to construct these geometries with vanishing amounts of averaged null energy condition violating phantom energy. Specific wormhole dimensions and the traversal velocity and time are also deduced from the traversability conditions for a particular wormhole geometry. These phantom energy traversable wormholes have far-reaching physical and cosmological implications. For instance, an advanced civilization may use these geometries to induce closed timelike curves, consequently violating causality.Comment: 9 pages, Revtex4. V2: Considerable comments and references added, no physics changes, now 10 pages. Accepted for publication in Physical Review

A Study of Water Clusters Using the Effective Fragment Potential and Monte Carlo Simulated Annealing

Simulated annealing methods have been used with the effective fragment potential to locate the lowest energy structures for the water clusters (H2O)n with n=6, 8, 10, 12, 14, 16, 18, and 20. The most successful method uses a local minimization on each Monte Carlo step. The effective fragment potential method yielded interaction energies in excellent agreement with those calculated at the ab initio Hartree–Fock level and was quite successful at predicting the same energy ordering as the higher-level perturbation theory and coupled cluster methods. Analysis of the molecular interaction energies in terms of its electrostatic,polarization, and exchange-repulsion/charge-transfer components reveals that the electrostatic contribution is the dominant term in determining the energy ordering of the minima on the (H2O)n potential energy surfaces, but that differences in the polarization and repulsion components can be important in some cases

QED Calculation of E1M1 and E1E2 Transition Probabilities in One-Electron Ions with Arbitrary Nuclear Charge

The quantum electrodynamical theory of the two-photon transitions in hydrogenlike ions is presented. The emission probability for 2s1/2 -> 2E1+1s1/2 transitions is calculated and compared to the results of the previous calculations. The emission probabilities 2p12 -> E1E2+1s1/2 and 2p1/2 -> E1M1+1s1/2 are also calculated for the nuclear charge Z values 1-100. This is the first calculation of the two latter probabilities. The results are given in two different gauges.Comment: 14 pages, 4 tables, 1 figur

Transport-Health Equity Outcomes from mobile phone location data - a case study

The digital media convergence has innovated all the information and communication channels. ICTs have adapted to the reticular structure, which can be interpreted as a paradigm of today's Network Society, invoking a reorganization of man-machine relationship, interpersonal interactions and the ways of collecting, processing and storing data. Political communication and its processes of participation are not exempt from this evident change. The aim of this paper is to investigate the transformation dynamics that have taken place through the Internet and social networks, as effectively more democratic tools that are able to stimulate a bottom-up and grassroots participation, in some respects a disintermediate participation compared to the typical unidirectionality of analogue media. In identifying the specific characteristics of the interaction spaces offered by the web, we have examined the digital campaign strategy devised by the political parties during the Italian general election (4th March 2018). The results have returned an unprecedented scenario, in which the social media strategy plays a leading role in the different dimensions of political marketing. The web is proposed to become the ideal social arena for the meeting between political offer and demand

Two-particle photoemission from strongly correlated systems: A dynamical-mean field approach

We study theoretically the simultaneous, photo-induced two-particle excitations of strongly correlated systems on the basis of the Hubbard model. Under certain conditions specified in this work, the corre- sponding transition probability is related to the two-particle spectral function which we calculate using three different methods: the dynamical-mean field theory combined with quantum Monte Carlo (DMFT- QMC) technique, the first order perturbation theory and the ladder approximations. The results are analyzed and compared for systems at the verge of the metal-insulator transitions. The dependencies on the electronic correlation strength and on doping are explored. In addition, the account for the orbital degeneracy allows an insight into the influence of interband correlations on the two particle excitations. A suitable experimental realization is discussed.Comment: 25 pp, 10 figs. to be published in PR

Defects, order, and hysteresis in driven charge-density waves

We model driven two-dimensional charge-density waves in random media via a modified Swift-Hohenberg equation, which includes both amplitude and phase fluctuations of the condensate. As the driving force is increased, we find that the defect density first increases and then decreases. Furthermore, we find switching phenomena, due to the formation of channels of dislocations. These results are in qualitative accord with recent dynamical x-ray scattering experiments by Ringlandet al. and transport experiments by Lemay et al.Comment: Accepted to Phys. Rev. Lett. Click here for "http://www-theory.mpip-mainz.mpg.de/~karttune/CDW/", movies of driven CDW

Relativistic Symmetry Suppresses Quark Spin-Orbit Splitting

Experimental data indicate small spin-orbit splittings in hadrons. For heavy-light mesons we identify a relativistic symmetry that suppresses these splittings. We suggest an experimental test in electron-positron annihilation. Furthermore, we argue that the dynamics necessary for this symmetry are possible in QCD.Comment: 16 pages, LaTeX. Two postscript figures. Final version to be published in Physical Review Letter

Meeting the communication support needs of children and young people with intellectual disabilities in the Bolivian Andes

Services available for people with disabilities in Bolivia tend to be fragmented and costly. Children and adults with intellectual disabilities are more likely to have a related communication disability and are thus both literally and metaphorically excluded from having a voice. The following research aimed to explore the experiences of accessing services by people with communication disabilities in Bolivia through semi-structured interviews and one focus group carried out with family members, professionals, service providers, educators and policymakers. It aimed to establish the nature of current services in Bolivia where knowledge, information and resources are scarce. Findings indicated the need to consider an alternative to a medical model approach through a focus on empowering other stakeholders to participate more fully in meeting communication support needs. Conclusions plot ideas for future service delivery and emphasize the central power of sharing practical and expert knowledge

Building professional discourse in emerging markets: Language, context and the challenge of sensemaking

Using ethnographic evidence from the former Soviet republics, this article examines a relatively new and mainly unobserved in the International Business (IB) literature phenomenon of communication disengagement that manifests itself in many emerging markets. We link it to the deficiencies of the local professional business discourse rooted in language limitations reflecting lack of experience with the market economy. This hampers cognitive coherence between foreign and local business entities, adding to the liability of foreignness as certain instances of professional experience fail to find adequate linguistic expression, and complicates cross-cultural adjustments causing multi-national companies (MNCs) financial losses. We contribute to the IB literature by examining cross-border semantic sensemaking through a retrospectively constructed observational study. We argue that a relative inadequacy of the national professional idiom is likely to remain a feature of business environment in post-communist economies for some time and therefore should be factored into business strategies of MNCs. Consequently, we recommend including discursive hazards in the risk evaluation of international projects