2D Black Hole and Holographic Renormalization Group

In hep-th/0311177, the Large $N$ renormalization group (RG) flows of a modified matrix quantum mechanics on a circle, capable of capturing effects of nonsingets, were shown to have fixed points with negative specific heat. The corresponding rescaling equation of the compactified matter field with respect to the RG scale, identified with the Liouville direction, is used to extract the two dimensional Euclidean black hole metric at the new type of fixed points. Interpreting the large $N$ RG flows as flow velocities in holographic RG in two dimensions, the flow equation of the matter field around the black hole fixed point is shown to be of the same form as the radial evolution equation of the appropriate bulk scalar coupled to 2D black hole.Comment: 21 page

Two-step melting of the vortex solid in layered superconductors with random columnar pins

We consider the melting of the vortex solid in highly anisotropic layered superconductors with a small concentration of random columnar pinning centers. Using large-scale numerical minimization of a free-energy functional, we find that melting of the low-temperature, nearly crystalline vortex solid (Bragg glass) into a vortex liquid occurs in two steps as the temperature increases: the Bragg glass and liquid phases are separated by an intermediate Bose glass phase. A suitably defined local melting temperature exhibits spatial variation similar to that observed in experiments.Comment: To appear in Phys. Rev. Let

The Qt distribution of the Breit current hemisphere in DIS as a probe of small-x broadening effects

We study the distribution 1/sigma dsigma/dQt, where Qt is the modulus of the transverse momentum vector, obtained by summing over all hadrons, in the current hemisphere of the DIS Breit frame. We resum the large logarithms in the small Qt region, to next-to--leading logarithmic accuracy, including the non-global logarithms involved. We point out that this observable is simply related to the Drell-Yan vector boson and predicted Higgs Qt spectra at hadron colliders. Comparing our predictions to existing HERA data thus ought to be a valuable source of information on the role or absence of small-x (BFKL) effects, neglected in conventional resummations of such quantities.Comment: 16 pages, 3 figures, uses JHEP3.cl

Spatial persistence and survival probabilities for fluctuating interfaces

We report the results of numerical investigations of the steady-state (SS) and finite-initial-conditions (FIC) spatial persistence and survival probabilities for (1+1)--dimensional interfaces with dynamics governed by the nonlinear Kardar--Parisi--Zhang (KPZ) equation and the linear Edwards--Wilkinson (EW) equation with both white (uncorrelated) and colored (spatially correlated) noise. We study the effects of a finite sampling distance on the measured spatial persistence probability and show that both SS and FIC persistence probabilities exhibit simple scaling behavior as a function of the system size and the sampling distance. Analytical expressions for the exponents associated with the power-law decay of SS and FIC spatial persistence probabilities of the EW equation with power-law correlated noise are established and numerically verified.Comment: 11 pages, 5 figure

Effect of spin orbit coupling and Hubbard UU on the electronic structure of IrO2_2

We have studied in detail the electronic structure of IrO$_2$ including spin-orbit coupling (SOC) and electron-electron interaction, both within the GGA+U and GGA+DMFT approximations. Our calculations reveal that the Ir t$_{2g}$ states at the Fermi level largely retain the J$_{\rm eff}$ = $\frac{1}{2}$ character, suggesting that this complex spin-orbit entangled state may be robust even in metallic IrO$_2$. We have calculated the phase diagram for the ground state of IrO$_2$ as a function of $U$ and find a metal insulator transition that coincides with a magnetic phase change, where the effect of SOC is only to reduce the critical values of $U$ necessary for the transition. We also find that dynamic correlations, as given by the GGA+DMFT calculations, tend to suppress the spin-splitting, yielding a Pauli paramagnetic metal for moderate values of the Hubbard $U$. Our calculated optical spectra and photoemission spectra including SOC are in good agreement with experiment demonstrating the importance of SOC in IrO$_2$