Metal-insulator transition in two-dimensional disordered systems with power-law transfer terms

We investigate a disordered two-dimensional lattice model for noninteracting electrons with long-range power-law transfer terms and apply the method of level statistics for the calculation of the critical properties. The eigenvalues used are obtained numerically by direct diagonalization. We find a metal-insulator transition for a system with orthogonal symmetry. The exponent governing the divergence of the correlation length at the transition is extracted from a finite size scaling analysis and found to be $\nu=2.6\pm 0.15$. The critical eigenstates are also analyzed and the distribution of the generalized multifractal dimensions is extrapolated.Comment: 4 pages with 4 figures, printed version: PRB, Rapid Communication

Nonlinear σ\sigma model for disordered superconductors

We suggest a novel nonlinear $\sigma$-model for the description of disordered superconductors. The main distinction from existing models lies in the fact that the saddle point equation is solved non-perturbatively in the superconducting pairing field. It allows one to use the model both in the vicinity of the metal-superconductor transition and well below its critical temperature with full account for the self-consistency conditions. We show that the model reproduces a set of known results in different limiting cases, and apply it for a self-consistent description of the proximity effect at the superconductor-metal interface.Comment: Revised version, 8 pages, 1 fig., revtex; final version, as published, contains a few corrections in the summar

Azimuthal anisotropy of K0s and Lambda prduction at mid-rapidity from Au+Au collisions at root s = 130 GeV

We report STAR results on the azimuthal anisotropy parameter v2 for strange particles K0S, L and Lbar at midrapidity in Au+Au collisions at sNN = 130 GeV at RHIC. The value of v2 as a function of transverse momentum of the produced particles pt and collision centrality is presented for both particles up to pt 3.0 GeV/c. A strong pt dependence in v2 is observed up to 2.0 GeV/c. The v2 measurement is compared with hydrodynamic model calculations. The physics implications of the pt integrated v2 magnitude as a function of particle mass are also discussed.Comment: 6 pages, 4 figures, by the STAR collaboratio

K⋆(892)0K^{\star}(892)^{0} Production in Relativistic Heavy Ion Collisions at sNN=130\sqrt{s_{_{NN}}}=130 GeV

We report the first observation of $K^{\star}(892)^{0}\to\pi K$ in relativistic heavy ion collisions. The transverse momentum spectrum of $(K^{\star0}+\bar{K}^{\star0})/2$ from central Au+Au collisions at $\sqrt{s_{_{NN}}}=130$ GeV is presented. The ratios of the $K^{\star0}$ yield derived from these data to the yields of negative hadrons, charged kaons, and $\phi$ mesons have been measured in central and minimum bias collisions and compared with model predictions and comparable $e^{+}e^{-}$, $pp$, and $\bar{p}p$ results. The data indicate no dramatic reduction of $K^{\star0}$ production in relativistic heavy ion collisions despite expected losses due to rescattering effects.Comment: 6 pages, 3 figures, To be published in PRC