4,018 research outputs found
Extremal maps of the universal hyperbolic solenoid
We show that the set of points in the Teichmuller space of the universal
hyperbolic solenoid which do not have a Teichmuller extremal representative is
generic (that is, its complement is the set of the first kind in the sense of
Baire). This is in sharp contrast with the Teichmuller space of a Riemann
surface where at least an open, dense subset has Teichmuller extremal
representatives. In addition, we provide a sufficient criteria for the
existence of Teichmuller extremal representatives in the given homotopy class.
These results indicate that there is an interesting theory of extremal (and
uniquely extremal) quasiconformal mappings on hyperbolic solenoids.Comment: LaTeX, 15 page
Harmonic diffeomorphisms of noncompact surfaces and Teichmüller spaces
Let g : M -> N be a quasiconformal harmonic diffeomorphism between noncompact Riemann surfaces M and N. In this paper we study the relation between the map g and the complex structures given on M and N. In the case when M and N are of finite analytic type we derive a precise estimate which relates the map g and the Teichmüller distance between complex structures given on M and N. As a corollary we derive a result that every two quasiconformally related finitely generated Kleinian groups are also related by a harmonic diffeomorphism. In addition, we study the question of whether every quasisymmetric selfmap of the unit circle has a quasiconformal harmonic extension to the unit disk. We give a partial answer to this problem. We show the existence of the harmonic quasiconformal extensions for a large class of quasisymmetric maps. In particular it is proved that all symmetric selfmaps of the unit circle have a unique quasiconformal harmonic extension to the unit disk
On the Zeros of Functions in the Bers Space
We present some results on the distribution of zeros of functions in the Bers space Q(D), showing how the distribution depends on the bounds of the growth of │ƒ(z)│ HS │z│ƒ → 1, for ƒ Є Q(D). We also exhibit an open and dense subset, M C Q(D), which has the property of uniform control over the number of zeros in disks of hyperbolic radius l containes in D
Isometries between the spaces of L^1 holomorphic quadratic differentials on Riemann surfaces of finite type
By applying the methods of V. Markovic [7] to the special case of Riemann surfaces of finite type, we obtain a transparent new proof of a classical result about isometries between the spaces of L^1 holomorphic quadratic differentials on such surfaces
Convex regions in the plane and their domes
We make a detailed study of the relation of a euclidean convex region to . The dome is the relative boundary, in the upper halfspace model of hyperbolic space, of the hyperbolic convex hull of the complement of . The first result is to prove that the nearest point retraction is 2-quasiconformal. The second is to establish precise estimates of the distortion of near
Imaging the charge transport in arrays of CdSe nanocrystals
A novel method to image charge is used to measure the diffusion coefficient
of electrons in films of CdSe nanocrystals at room temperature. This method
makes possible the study of charge transport in films exhibiting high
resistances or very small diffusion coefficients.Comment: 4 pages, 4 jpg figure
Heart rate and lactate responses to taekwondo fight in elite women performers
The purpose of this study was to examine heart rate (HR) and blood lactate (LA) concentration before, during and after a competitive Tae kwon do (TKD) fight performed by elite women performers. Specifically, we were interested to see weather HR and LA responses to competitive fight were greater than to TKD or karate exercises published in scientific literature. Seven international-standard women TKD fighters participated in the study. HR was recorded continuously throughout the fight using Polar Vantage telemetric HR monitors. LA samples were taken before and 3 min after the fight and analysed using an Accusport portable lactate analyzer. At the beginning of the fight, HR significantly increased (p<0.01) from pre-fight values of 91.6±9.9 beats min-1 to 144.1±13.6 beats min-1. During the whole fight the HRmean was 186.6±2.5 beats min-1 and remained significantly elevated (p<0.01) at 3 min into recovery. HR values expressed as a percentage of HRmax averaged during the whole fight at 91.7±2.6% respectively. LA concentration significantly increased (p<0.01) 3 min after the fight and averaged 82% of LApeak values measured after the VO2max test. Results of the present study indicate that physiological demands of competitive TKD fight in women, measured by HR and LA responses, are considerably higher than the physiological demands of TKD or karate training exercises. The observed HR and LA responses suggest to us that conditioning for TKD should generally emphasise high-intensity anaerobic exercise
Gravitational Collapse of Dust with a Cosmological Constant
The recent analysis of Markovic and Shapiro on the effect of a cosmological
constant on the evolution of a spherically symmetric homogeneous dust ball is
extended to include the inhomogeneous and degenerate cases. The histories are
shown by way of effective potential and Penrose-Carter diagrams.Comment: 2 pages, 2 figures (png), revtex. To appear in Phys. Rev.
Granulated superconductors:from the nonlinear sigma model to the Bose-Hubbard description
We modify a nonlinear sigma model (NLSM) for the description of a granulated
disordered system in the presence of both the Coulomb repulsion and the Cooper
pairing. We show that under certain controlled approximations this model is
reduced to the Bose-Hubbard (or ``dirty-boson'') model with renormalized
coupling constants. We obtain a more general effective action (which is still
simpler than the full NLSM action) which can be applied in the region of
parameters where the reduction to the Bose-Hubbard model is not justified. This
action may lead to a different picture of the superconductor-insulator
transition in 2D systems.Comment: 4 pages, revtex, no figure
Convective Term and Transversely Driven Charge-Density Waves
We derive the convective terms in the damping which determine the structure
of the moving charge-density wave (CDW), and study the effect of a current
flowing transverse to conducting chains on the CDW dynamics along the chains.
In contrast to a recent prediction we find that the effect is orders of
magnitude smaller, and that contributions from transverse currents of electron-
and hole-like quasiparticles to the force exerted on the CDW along the chains
act in the opposite directions. We discuss recent experimental verification of
the effect and demonstrate experimentally that geometry effects might mimic the
transverse current effect.Comment: RevTeX, 9 pages, 1 figure, accepted for publications in PR
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