We study the correlators of a recently discovered family of BPS Wilson loops in N = 4 supersymmetric U (N ) Yang-Mills theory. When the contours lie on a two-sphere in the space-time, we propose a closed expression that is valid for all values of the coupling constant g and for any rank N , by exploiting the suspected relation with two-dimensional gauge theories. We check this formula perturbatively at order O(g 4 ) for two latitude Wilson loops and we show that, in the limit where one of the loops shrinks to a point, logarithmic corrections in the shrinking radius are absent at O(g 6 ). This last result strongly supports the validity of our general expression and suggests the existence of a peculiar protected local operator arising in the OPE of the Wilson loop. At strong coupling we compare our result to the string dual of the N = 4 SYM correlator in the limit of large separation, presenting some preliminary evidence for the agreement.

We continue our study of the correlators of a recently discovered family of BPS Wilson loops in N=4 supersymmetric U(N) Yang-Mills theory. We perform explicit computations at weak coupling by means of analytical and numerical methods finding agreement with the exact formula derived from localization. In particular we check the localization prediction at order g^6 for different BPS "latitude" configurations, the N=4 perturbative expansion reproducing the expected results within a relative error of 10^(-4). On the strong coupling side we present a supergravity evaluation of the 1/8 BPS correlator in the limit of large separation, taking into account the exchange of all relevant modes between the string world-sheets. While reproducing the correct geometrical dependence, we find that the associated coefficient does not match the localization result.Comment: 34 pages, 16 figure

We show how the Weyl formalism allows metrics to be written down which correspond to arbitrary numbers of collinear accelerating neutral black holes in 3+1 dimensions. The black holes have arbitrary masses and different accelerations and share a common acceleration horizon. In the general case, the black holes are joined by cosmic strings or struts that provide the necessary forces that, together with the inter black hole gravitational attractions, produce the acceleration. In the cases of two and three black holes, the parameters may be chosen so that the outermost black hole is pulled along by a cosmic string and the inner black holes follow behind accelerated purely by gravitational forces. We conjecture that similar solutions exist for any number of black holes. a f.dowker@qmw.ac.uk, b thamby@physics.harvard.edu.

We investigate the discretized version of the compact Randall-Sundrum model. By studying the mass eigenstates of the lattice theory, we demonstrate that for warped space, unlike for flat space, the strong coupling scale does not depend on the IR scale and lattice size. However, strong coupling does prevent us from taking the continuum limit of the lattice theory. Nonetheless, the lattice theory works in the manifestly holographic regime and successfully reproduces the most significant features of the warped theory. It is even in some respects better than the KK theory, which must be carefully regulated to obtain the correct physical results. Because it is easier to construct lattice theories than to find exact solutions to GR, we expect lattice gravity to be a useful tool for exploring field theory in curved space.