Coarse-Graining the Lin-Maldacena Geometries

The Lin-Maldacena geometries are nonsingular gravity duals to degenerate vacuum states of a family of field theories with SU(2|4) supersymmetry. In this note, we show that at large N, where the number of vacuum states is large, there is a natural `macroscopic' description of typical states, giving rise to a set of coarse-grained geometries. For a given coarse-grained state, we can associate an entropy related to the number of underlying microstates. We find a simple formula for this entropy in terms of the data that specify the geometry. We see that this entropy function is zero for the original microstate geometries and maximized for a certain ``typical state'' geometry, which we argue is the gravity dual to the zero-temperature limit of the thermal state of the corresponding field theory. Finally, we note that the coarse-grained geometries are singular if and only if the entropy function is non-zero.Comment: 29 pages, LaTeX, 3 figures; v2 references adde

Cross section normalization in proton-proton collisions at s\sqrt{s} = 2.76 TeV and 7 TeV, with ALICE at LHC

Measurements of the cross sections of the reference processes seen by the ALICE trigger system were obtained based on beam properties measured from van der Meer scans. The measurements are essential for absolute cross section determinations of physics processes. The paper focuses on instrumental and technical aspects of detectors and accelerators, including a description of the extraction of beam properties from the van der Meer scan. As a result, cross sections of reference processes seen by the ALICE trigger system are given for proton-proton collisions at two energies; $\sqrt{s}$=2.76 TeV and 7 TeV, together with systematic uncertainties originating from beam intensity measurements and other detector effects. Consistency checks were performed by comparing to data from other experiments in LHC.Comment: Quark Matter 2011 Conference Proceedings, 4 pages, 2 figure

T-duality, Fiber Bundles and Matrices

We extend the T-duality for gauge theory to that on curved space described as a nontrivial fiber bundle. We also present a new viewpoint concerning the consistent truncation and the T-duality for gauge theory and discuss the relation between the vacua on the total space and on the base space. As examples, we consider S^3(/Z_k), S^5(/Z_k) and the Heisenberg nilmanifold.Comment: 24 pages, typos correcte

The young star cluster system of the Antennae galaxies

“The original publication is available at www.springerlink.com”. Copyright Springer. DOI: 10.1007/s10509-009-0103-xThe study of young star cluster (YSC) systems, preferentially in starburst and merging galaxies, has seen great interest in the recent past, as it provides important input to models of star formation. However, even some basic properties (such as the luminosity function; LF) of YSC systems are still being debated. Here, we study the photometric properties of the YSC system in the nearest major merger system, the Antennae galaxies. We find evidence for the existence of a statistically significant turnover in the LF.Peer reviewe

First Results from Lattice Simulation of the PWMM

We present results of lattice simulations of the Plane Wave Matrix Model (PWMM). The PWMM is a theory of supersymmetric quantum mechanics that has a well-defined canonical ensemble. We simulate this theory by applying rational hybrid Monte Carlo techniques to a naive lattice action. We examine the strong coupling behaviour of the model focussing on the deconfinement transition.Comment: v3 20 pages, 8 figures, comment adde

Little String Theory from Double-Scaling Limits of Field Theories

We show that little string theory on S^5 can be obtained as double-scaling limits of the maximally supersymmetric Yang-Mills theories on RxS^2 and RxS^3/Z_k. By matching the gauge theory parameters with those in the gravity duals found by Lin and Maldacena, we determine the limits in the gauge theories that correspond to decoupling of NS5-brane degrees of freedom. We find that for the theory on RxS^2, the 't Hooft coupling must be scaled like ln^3(N), and on RxS^3/Z_k, like ln^2(N). Accordingly, taking these limits in these field theories gives Lagrangian definitions of little string theory on S^5.Comment: 16 pages, 5 figures. Minor change

Weak continuous monitoring of a flux qubit using coplanar waveguide resonator

We study a flux qubit in a coplanar waveguide resonator by measuring transmission through the system. In our system with the flux qubit decoupled galvanically from the resonator, the intermediate coupling regime is achieved. In this regime dispersive readout is possible with weak backaction on the qubit. The detailed theoretical analysis and simulations give a good agreement with the experimental data and allow to make the qubit characterization.Comment: 4 pages, 3 figures, to be published in Phys. Rev.

Bounces/Dyons in the Plane Wave Matrix Model and SU(N) Yang-Mills Theory

We consider SU(N) Yang-Mills theory on the space R^1\times S^3 with Minkowski signature (-+++). The condition of SO(4)-invariance imposed on gauge fields yields a bosonic matrix model which is a consistent truncation of the plane wave matrix model. For matrices parametrized by a scalar \phi, the Yang-Mills equations are reduced to the equation of a particle moving in the double-well potential. The classical solution is a bounce, i.e. a particle which begins at the saddle point \phi=0 of the potential, bounces off the potential wall and returns to \phi=0. The gauge field tensor components parametrized by \phi are smooth and for finite time both electric and magnetic fields are nonvanishing. The energy density of this non-Abelian dyon configuration does not depend on coordinates of R^1\times S^3 and the total energy is proportional to the inverse radius of S^3. We also describe similar bounce dyon solutions in SU(N) Yang-Mills theory on the space R^1\times S^2 with signature (-++). Their energy is proportional to the square of the inverse radius of S^2. From the viewpoint of Yang-Mills theory on R^{1,1}\times S^2 these solutions describe non-Abelian (dyonic) flux tubes extended along the x^3-axis.Comment: 11 pages; v2: one formula added, some coefficients correcte

Shape and Interaction Decoupling for Colloidal Pre-Assembly

Creating materials with a structural hierarchy that is independently controllable at a range of scales requires breaking naturally occurring hierarchies. Breaking natural hierarchies is possible if building block attributes can be decoupled from the structure of pre-assembled, mesoscale building blocks that form the next level in the structural hierarchy. Here, we show that pre-assembled colloidal structures achieving geometric and interaction decoupling can be prepared in emulsions of silica superballs, which are cubic-like particles with rounded edges. We show that, for clusters of up to nine particles, colloidal superballs pack consistently like spheres, despite the presence of shape anisotropy and facets in the cubic-like particles. We compare our results with clusters prepared with magnetic superballs and find good qualitative agreement, suggesting that the cluster geometries are solely determined by the shape of the constituent particles. Our findings demonstrate that highly shape-anisotropic building blocks, under suitable conditions, can be pre-assembled into structures that are not found in bulk, thereby achieving a decoupling that can be further exploited for hierarchical materials development.Comment: 22 pages, 7 figure