B-splines, Pólya curves, and duality

AbstractLocal duality between B-splines and Pólya curves is examined, mostly from the viewpoint of computer-aided geometric design. Certain known results for the two curve types are shown to be related. A few new results for Pólya curves and a curve scheme related to B-splines also follow from these investigations

Quantum chromodynamics quark benzene

A six-quark state with the benzene-like structure is proposed and studied based on color string model. The calculation with the quadratic confinement show that such structure has the lowest energy among the various hidden color six-quark structures proposed so far. Its possible effect on $NN$ scattering is discussed.Comment: 5 pages, 7 figure

Imagery rescripting for the treatment of trauma in voice hearers: a case series

Background: High rates of trauma and post-traumatic stress disorder (PTSD) are reported in people who hear voices (auditory hallucinations). A recent metanalysis of trauma interventions in psychosis showed only small improvements in PSTD symptoms and voices. Imagery Rescripting (ImRs) may be a therapy that is more effective in this population because it generalizes over memories, which is ideal in this population with typically repeated traumas. The primary aims of this study were to investigate whether ImR reduces (1) PTSD symptoms and (2) voice frequency and distress in voice hearers. Methods: A single arm open trial study, case-series design. Twelve voice hearers with previous traumas that were thematically related to their voices participated. Brief weekly assessments (administered sessions 1-8, post-intervention, and 3-month follow-up) and longer measures (administered pre-, mid-, and post-intervention) were administered. Mixed regression analysis was used to analyze the results. Results: There was one treatment dropout. Results of the weekly measure showed significant linear reductions over time in all three primary variables - Voice Distress, Voice Frequency, and Trauma Intrusions - all with large effect sizes. These effects were maintained (and continued to improve for Trauma Intrusions) at 3-month follow-up. On the full assessment tools, all measures showed improvement over time, with five outcomes showing significant time effects: trauma, voice frequency, voice distress, voice malevolence and stress. Conclusion: The findings of the current study suggest that ImRs for PTSD symptoms is generally well tolerated and can be therapeutically beneficial among individuals who hear voices

Quark Delocalization, Color Screening Model and Nucleon-Baryon Scattering

We apply the quark delocalization and color screening model to nucleon-baryon scattering. A semi-quantitative fit to N-N, N-Lambda and N-Sigma phase shifts and scattering cross sections is obtained without invoking meson exchange. Quarks delocalize reasonably in all of the different flavor channels to induce effective nucleon-baryon interactions with both a repulsive core and with an intermediate range attraction in the cases expected.Comment: 14 pp. RevTeX plus 13 figs.ps, submitted to Phys. Rev.

Correlated transport of FQHE quasiparticles in a double-antidot system

We have calculated the linear conductance associated with tunneling of individual quasiparticles of primary quantum Hall liquids with filling factors $\nu =1/(2m+1)$ through a system of two antidots in series. On-site Coulomb interaction simulates the Fermi exclusion and makes the quasiparticle dynamics similar to that of tunneling electrons. The liquid edges serve as the quasiparticle reservoirs, and also create the dissipation mechanism for tunneling between the antidots. In the regime of strong dissipation, the conductance should exhibit resonant peaks of unusual form and a width proportional to the quasiparticle interaction energy $U$. In the weakly-damped regime, the shape of the resonant conductance peaks reflects coherent tunnel coupling of the antidots. The Luttinger-liquid singularity in the rates of quasiparticle tunneling to/from the liquid edges manifests itself as an additional weak resonant structure in the conductance curves.Comment: 9 pages including 5 figure

A two-point function approach to connectedness of drops in convex potentials

We establish connectedness of volume constrained minimisers of energies involving surface tensions and convex potentials. By a previous result of McCann, this implies that minimisers are convex in dimension two. This positively answers an old question of Almgren. We also prove convexity of minimisers when the volume constraint is dropped. Our proof is based on the introduction of a new "two-point function" which measures the lack of convexity and which gives rise to a negative second variation of the energy

Energetics of Quantum Antidot States in Quantum Hall Regime

We report experiments on the energy structure of antidot-bound states. By measuring resonant tunneling line widths as function of temperature, we determine the coupling to the remote global gate voltage and find that the effects of interelectron interaction dominate. Within a simple model, we also determine the energy spacing of the antidot bound states, self consistent edge electric field, and edge excitation drift velocity.Comment: 4 pages, RevTex, 5 Postscript figure

Quantum irreversible decoherence behaviour in open quantum systems with few degrees of freedom. Application to 1H NMR reversion experiments in nematic liquid crystals

An experimental study of NMR spin decoherence in nematic liquid crystals (LC) is presented. Decoherence dynamics can be put in evidence by means of refocusing experiments of the dipolar interactions. The experimental technique used in this work is based on the MREV8 pulse sequence. The aim of the work is to detect the main features of the Irreversible Quantum Decoherence (IQD) in LC, on the basis of the theory presented by the authors recently. The focus is laid on experimentally probing the eigen-selection process in the intermediate time scale, between quantum interference of a closed system and thermalization, as a signature of the IQD of the open quantum system, as well as on quantifying the effects of non-idealities as possible sources of signal decays which could mask the intrinsic IQD. In order to contrast experiment and theory, the theory was adapted to obtain the IQD function corresponding to the MREV8 reversion experiments. Non-idealities of the experimental setting are analysed in detail within this framework and their effects on the observed signal decay are numerically estimated. It is found that, though these non-idealities could in principle affect the evolution of the spin dynamics, their influence can be mitigated and they do not present the characteristic behavior of the IQD. As unique characteristic of the IQD, the experimental results clearly show the occurrence of eigen-selectivity in the intermediate timescale, in complete agreement with the theoretical predictions. We conclude that the eigen-selection effect is the fingerprint of IQD associated with a quantum open spin system in LC. Besides, these features of the results account for the quasi-equilibrium states of the spin system, which were observed previously in these mesophases, and lead to conclude that the quasi-equilibrium is a definite stage of the spin dynamics during its evolution towards equilibriu