The origin of scale-scale correlations of the density perturbations during inflation

We show that scale-scale correlations are a generic feature of slow-roll inflation theories. These correlations result from the long-time tails characteristic of the time dependent correlations because the long wavelength density perturbation modes are diffusion-like. A relationship between the scale-scale correlations and time-correlations is established providing a way to reveal the time correlations of the perturbations during inflation. This mechanism provides for a testable prediction that the scale-scale correlations at two different spatial points will vanish.Comment: Accepted for publication, International Journal of Modern Physics, vol. 8 No.6 (Dec 1999

Luscher Term for k-string Potential from Holographic One Loop Corrections

We perform a systematic analysis of k-strings in the framework of the gauge/gravity correspondence. We discuss the Klebanov-Strassler supergravity background which is known to be dual to a confining supersymmetric gauge theory with chiral symmetry breaking. We obtain the k-string tension in agreement with expectations of field theory. Our main new result is the study of one-loop corrections on the string theoretic side. We explicitly find the frequency spectrum for both the bosons and the fermions for quadratic fluctuations about the classical supergravity solution. Further we use the massless modes to compute 1/L contributions to the one loop corrections to the k-string energy. This corresponds to the Luscher term contribution to the k-string potential on the gauge theoretic side of the correspondence.Comment: 39 pages, 3 figures. New Calculation showing explicit k -> M - k symmetry of Energy utilizing the new figure. Discussion of non-k-dependence of Luscher term at end of last section right before Conclusion. Same version to be published in JHE

Rapid Thermalization in Field Theory from Gravitational Collapse

Motivated by the duality with thermalization in field theory, we study gravitational collapse of a minimally coupled massless scalar field in Einstein gravity with a negative cosmological constant. We investigate the system numerically and establish that for small values of the initial amplitude of the scalar field there is no black hole formation, rather, the scalar field performs an oscillatory motion typical of geodesics in AdS. For large enough values of the amplitude of the scalar field we find black hole formation which we detect numerically as the emergence of an apparent horizon. Using the time of formation as an estimate for thermalization in the field theory we conclude that thermalization occurs very rapidly, close to the causal bound for a very wide range of black hole masses. We further study the thermalization time in more detail as a function of the amplitude and the width of the initial Gaussian scalar field profile and detect a rather mild structure.Comment: 5 pages, 4 figures. v2: References added, improved most grids by a factor of 8, main results unchanged. v3 PRD versio

Toward NS5 Branes on the Resolved Cone over Y^{p,q}

Motivated by recent developments in the understanding of the connection between five branes on resolved geometries and the corresponding generalizations of complex deformations in the context of the warped resolved deformed conifold, we consider the construction of five branes solutions on the resolved cone over Y^{p,q} spaces. We establish the existence of supersymmetric five branes solutions wrapped on two-cycles of the resolved cone over Y^{p,q} in the probe limit. We then use calibration techniques to begin the construction of fully back-reacted five branes; we present an Ansatz and the corresponding equations of motion. Our results establish a detailed framework to study back-reacted five branes wrapped on the resolved cone over Y^{p,q} and as a first step we find explicit solutions and construct an asymptotic expansion with the expected properties.Comment: 23+17pp, no figures; v2: references added, various clarification

Antarctic Meteorites: A Statistical Look at a Uniquely Valuable Resource

As of the end of the 2018-19 field season, the U.S. Antarctic meteorite program has surpassed 23,000 meteorites collected. The U.S. collection is valuable in that it is classified in its entirety. The systematic methods employed to collect the meteorites have provided meteorites of more than 40 types, many of which are the first of their type ever recognized. One of the early drivers for consistent and methodical characterization of the entire U.S. Antarctic collection was to allow statistical comparisons. Early statistical assessments of the U.S. Antarctic collection examined mass distributions and the relative frequency of meteorite types as well as comparisons to a defined set of modern falls. Using these statistics argued that the flux of H chondrites changed over time used model size distributions to deconstruct the contribution of wind movement, meteorite supply and search losses to the Antarctic collection. Mass-based statistics and size distribution comparisons were examined by investigated various aspects of the statistics, including comparison with modern falls/Saharan finds. Also discuss geospatial statistics provides a comprehensive overview of the statistics of the Antarctic collections for the first 35 seasons of U.S. collection by ANSMET. Here we build upon that assessment and that from

Analytic Non-integrability in String Theory

Using analytic techniques developed for Hamiltonian dynamical systems we show that a certain classical string configurations in AdS_5 x X_5 with X_5 in a large class of Einstein spaces, is non-integrable. This answers the question of integrability of string on such backgrounds in the negative. We consider a string localized in the center of AdS_5 that winds around two circles in the manifold X_5.Comment: 14 page

Turbulence and Chaos in Anti-de-Sitter Gravity

Due to the AdS/CFT correspondence the question of instability of Anti-de-Sitter spacetimes sits in the intersection of mathematical and numerical relativity, string theory, field theory and condensed matter physics. In this essay we revisit that important question emphasizing the power of spectral methods and highlighting the effectiveness of standard techniques for studying nonlinear dynamical systems. In particular we display explicitly how the problem can be modeled as a system on nonlinearly coupled harmonic oscillators. We highlight some of the many open questions that stem from this result and point out that a full understanding will necessarily required the interdisciplinary cooperation of various communities.Comment: 6 pages, 12 figures. Essay awarded honorable mention in the Gravity Research Foundation essay competition 201

One-point Statistics of the Cosmic Density Field in Real and Redshift Spaces with A Multiresolutional Decomposition

In this paper, we develop a method of performing the one-point statistics of a perturbed density field with a multiresolutional decomposition based on the discrete wavelet transform (DWT). We establish the algorithm of the one-point variable and its moments in considering the effects of Poisson sampling and selection function. We also establish the mapping between the DWT one-point statistics in redshift space and real space, i.e. the algorithm for recovering the DWT one-point statistics from the redshift distortion of bulk velocity, velocity dispersion, and selection function. Numerical tests on N-body simulation samples show that this algorithm works well on scales from a few hundreds to a few Mpc/h for four popular cold dark matter models. Taking the advantage that the DWT one-point variable is dependent on both the scale and the shape (configuration) of decomposition modes, one can design estimators of the redshift distortion parameter (beta) from combinations of DWT modes. When the non-linear redshift distortion is not negligible, the beta estimator from quadrupole-to-monopole ratio is a function of scale. This estimator would not work without adding information about the scale-dependence, such as the power-spectrum index or the real-space correlation function of the random field. The DWT beta estimators, however, do not need such extra information. Numerical tests show that the proposed DWT estimators are able to determine beta robustly with less than 15% uncertainty in the redshift range 0 < z < 3.Comment: 39 pages, 12 figures, ApJ accepte