Two Polyakov Loop Correlators from D5-branes at Finite Temperature

We study two Polyakov loop correlators in large $N$ limit of ${\cal{N}}=4$ super Yang-Mills theory at finite temperature using the AdS-Schwarzschild black hole. In the case that one of the two loops is of the anti-symmetric representation, we use D5-branes to evaluate them. The phase structure of these correlators is also examined. A previous result, derived in hep-th/9803135 and hep-th/9803137, is realized as a limiting case.}Comment: 12 pages, 2 figure

Classical c=1 Tachyon Scattering and 1/2-BPS Correlators

We study the correlator of chiral primary operators in \Ncal=4 super Yang-Mills theory in large $N$ limit. Through the free fermion picture, we map the gauge group rank and R-charges in SYM to the Fermi level and tachyon momenta, respectively, in the c=1 matrix model. By doing so, it is seen that half-BPS correlators are reproduced by tree-level tachyon scattering amplitudes.Comment: 7 pages, v2: typos corrected and a reference added, v3: PTP versio

D-branes in the Lorentzian Melvin Geometry

We consider string theory on the Lorentzian Melvin geometry, which is obtained by analytically continuing the two-parameter Euclidean Melvin background. Because this model provides a solvable conformal field theory that describes time-dependent twisted string dynamics, we study the string one-loop partition function and the D-brane spectrum. We found that both the wrapping D2-brane and the codimension-one D-string emit winding strings, and this behavior can be traced to the modified open string Hamiltonian on these probe D-branes.Comment: 13 pages, v2,v3,v4: changes and references added, v5: final version in PT

Anisotropic finite-size scaling analysis of a three-dimensional driven-diffusive system

We study the standard three-dimensional driven diffusive system on a simple cubic lattice where particle jumps along a given lattice direction are biased by an infinitely strong field, while those along other directions follow the usual Kawasaki dynamics. Our goal is to determine which of the several existing theories for critical behavior is valid. We analyze finite-size scaling properties using a range of system shapes and sizes far exceeding previous studies. Four different analytic predictions are tested against the numerical data. Binder and Wang's prediction does not fit the data well. Among the two slightly different versions of Leung, the one including the effects of a dangerous irrelevant variable appears to be better. Recently proposed isotropic finite-size scaling is inconsistent with our data from cubic systems, where systematic deviations are found, especially in scaling at the critical temperature.Comment: 12 pages, 14 PS figures, RevTeX; extensively revise