345 research outputs found

    Multifractality of Hamiltonians with power-law transfer terms

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    Finite-size effects in the generalized fractal dimensions dqd_q are investigated numerically. We concentrate on a one-dimensional disordered model with long-range random hopping amplitudes in both the strong- and the weak-coupling regime. At the macroscopic limit, a linear dependence of dqd_q on qq is found in both regimes for values of q \alt 4g^{-1}, where gg is the coupling constant of the model.Comment: RevTex4, 5 two-column pages, 5 .eps figures, to be published in Phys. Rev.

    Multifractality of wavefunctions at the quantum Hall transition revisited

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    We investigate numerically the statistics of wavefunction amplitudes ψ(r)\psi({\bf r}) at the integer quantum Hall transition. It is demonstrated that in the limit of a large system size the distribution function of ψ2|\psi|^2 is log-normal, so that the multifractal spectrum f(α)f(\alpha) is exactly parabolic. Our findings lend strong support to a recent conjecture for a critical theory of the quantum Hall transition.Comment: 4 pages Late

    Multifractality and critical fluctuations at the Anderson transition

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    Critical fluctuations of wave functions and energy levels at the Anderson transition are studied for the family of the critical power-law random banded matrix ensembles. It is shown that the distribution functions of the inverse participation ratios (IPR) PqP_q are scale-invariant at the critical point, with a power-law asymptotic tail. The IPR distribution, the multifractal spectrum and the level statistics are calculated analytically in the limits of weak and strong couplings, as well as numerically in the full range of couplings.Comment: 14 pages, 13 eps figure

    f(α)f(\alpha) Multifractal spectrum at strong and weak disorder

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    The system size dependence of the multifractal spectrum f(α)f(\alpha) and its singularity strength α\alpha is investigated numerically. We focus on one-dimensional (1D) and 2D disordered systems with long-range random hopping amplitudes in both the strong and the weak disorder regime. At the macroscopic limit, it is shown that f(α)f(\alpha) is parabolic in the weak disorder regime. In the case of strong disorder, on the other hand, f(α)f(\alpha) strongly deviates from parabolicity. Within our numerical uncertainties it has been found that all corrections to the parabolic form vanish at some finite value of the coupling strength.Comment: RevTex4, 6 two-column pages, 4 .eps figures, new results added, updated references, to be published in Phys. Rev.

    Molecular structure and developmental expression of zebrafish atp2a genes

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    [[abstract]]We isolated two atp2a genes, atp2a1 and atp2a2a, from embryonic zebrafish. Amino acid sequences deduced from zebrafish atp2a genes are aligned with orthologue proteins from other species, the results showed that they share high percentage of identities (82%–94%) and acidic pIs (5.03–5.33). Whole mount in situ hybridization experiments showed that atp2a1 and atp2a2a are maternal inherited genes which can be detected at 1-cell stage embryos and express in the entire animal pole from 6 hours post-fertilization (hpf) to 12 hpf. At the later stages (48–96 hpf), expression of atp2a1 was restricted in head and trunk muscles as well as in some neurons. In contrast to the strongly expression of atp2a1 in head muscle, expression of atp2a2a was detected in head muscle in a fainter manner. In addition, transcripts of atp2a2a were observed in the developing heart during early cardiogenesis. The present studies not only help us to comparatively analyze atp2a genes across species, but also provide useful information about expressions during early embryogenesis that will help in further investigations of functional studies of Atp2a in the future.[[incitationindex]]SCI[[booktype]]紙

    Measurement of the splashback feature around SZ-selected Galaxy clusters with DES, SPT, and ACT

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    We present a detection of the splashback feature around galaxy clusters selected using the Sunyaev–Zel’dovich (SZ) signal. Recent measurements of the splashback feature around optically selected galaxy clusters have found that the splashback radius, rsp, is smaller than predicted by N-body simulations. A possible explanation for this discrepancy is that rsp inferred from the observed radial distribution of galaxies is affected by selection effects related to the optical cluster-finding algorithms. We test this possibility by measuring the splashback feature in clusters selected via the SZ effect in data from the South Pole Telescope SZ survey and the Atacama Cosmology Telescope Polarimeter survey. The measurement is accomplished by correlating these cluster samples with galaxies detected in the Dark Energy Survey Year 3 data. The SZ observable used to select clusters in this analysis is expected to have a tighter correlation with halo mass and to be more immune to projection effects and aperture-induced biases, potentially ameliorating causes of systematic error for optically selected clusters. We find that the measured rsp for SZ-selected clusters is consistent with the expectations from simulations, although the small number of SZ-selected clusters makes a precise comparison difficult. In agreement with previous work, when using optically selected redMaPPer clusters with similar mass and redshift distributions, rsp is ∼2σ smaller than in the simulations. These results motivate detailed investigations of selection biases in optically selected cluster catalogues and exploration of the splashback feature around larger samples of SZ-selected clusters. Additionally, we investigate trends in the galaxy profile and splashback feature as a function of galaxy colour, finding that blue galaxies have profiles close to a power law with no discernible splashback feature, which is consistent with them being on their first infall into the cluster

    ϒ production in p–Pb collisions at √sNN=8.16 TeV

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    ϒ production in p–Pb interactions is studied at the centre-of-mass energy per nucleon–nucleon collision √sNN = 8.16 TeV with the ALICE detector at the CERN LHC. The measurement is performed reconstructing bottomonium resonances via their dimuon decay channel, in the centre-of-mass rapidity intervals 2.03 < ycms < 3.53 and −4.46 < ycms < −2.96, down to zero transverse momentum. In this work, results on the ϒ(1S) production cross section as a function of rapidity and transverse momentum are presented. The corresponding nuclear modification factor shows a suppression of the ϒ(1S) yields with respect to pp collisions, both at forward and backward rapidity. This suppression is stronger in the low transverse momentum region and shows no significant dependence on the centrality of the interactions. Furthermore, the ϒ(2S) nuclear modification factor is evaluated, suggesting a suppression similar to that of the ϒ(1S). A first measurement of the ϒ(3S) has also been performed. Finally, results are compared with previous ALICE measurements in p–Pb collisions at √sNN = 5.02 TeV and with theoretical calculations.publishedVersio
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