The H.E.S.S. central data acquisition system

The High Energy Stereoscopic System (H.E.S.S.) is a system of Imaging Atmospheric Cherenkov Telescopes (IACTs) located in the Khomas Highland in Namibia. It measures cosmic gamma rays of very high energies (VHE; >100 GeV) using the Earth's atmosphere as a calorimeter. The H.E.S.S. Array entered Phase II in September 2012 with the inauguration of a fifth telescope that is larger and more complex than the other four. This paper will give an overview of the current H.E.S.S. central data acquisition (DAQ) system with particular emphasis on the upgrades made to integrate the fifth telescope into the array. At first, the various requirements for the central DAQ are discussed then the general design principles employed to fulfil these requirements are described. Finally, the performance, stability and reliability of the H.E.S.S. central DAQ are presented. One of the major accomplishments is that less than 0.8% of observation time has been lost due to central DAQ problems since 2009.Comment: 17 pages, 8 figures, published in Astroparticle Physic

On Dual Formulation for Higher Spin Gauge Fields in (A)dSd(A)dS_d

We obtain dual actions for spin $s \geq 2$ massless fields in $(A)dS_d$ by solving different algebraic constraints in the same first-order theory. Flat space dual higher spin actions obtained by Boulanger, Cnockaert and Henneaux \cite{BH} by solving differential constraints are shown to result from our formulation in a sort of quasi-classical approximation for the flat limit. The case of $s=2$ is considered in detail.Comment: LaTeX, 13 pages, no figure

Structural glass on a lattice in the limit of infinite dimensions

We construct a mean field theory for the lattice model of a structural glass and solve it using the replica method and one step replica symmetry breaking ansatz; this theory becomes exact in the limit of infinite dimensions. Analyzing stability of this solution we conclude that the metastable states remain uncorrelated in a finite temperature range below the transition, but become correlated at sufficiently low temperature. We find dynamic and thermodynamic transition temperatures as functions of the density and construct a full thermodynamic description of a typical physical process in which the system gets trapped in one metastable state when cooled below vitrification temperature. We find that for such physical process the entropy and pressure at the glass transition are continuous across the transition while their temperature derivatives have jumps.Comment: 4 pages, 2 figure

Replica symmetry breaking in long-range glass models without quenched disorder

We discuss mean field theory of glasses without quenched disorder focusing on the justification of the replica approach to thermodynamics. We emphasize the assumptions implicit in this method and discuss how they can be verified. The formalism is applied to the long range Ising model with orthogonal coupling matrix. We find the one step replica-symmetry breaking solution and show that it is stable in the intermediate temperature range that includes the glass state but excludes very low temperatures. At very low temperatures this solution becomes unstable and this approach fails.Comment: 6 pages, 2 figure

A p-Spin Interaction Ashkin-Teller Spin-Glass Model

A p-spin interaction Ashkin-Teller spin glass, with three independent Gaussian probability distributions for the exchange interactions, is studied by means of the replica method. A simple phase diagram is obtained within the replica-symmetric approximation, presenting an instability of the paramagnetic solution at low temperatures. The replica-symmetry-breaking procedure is implemented and a rich phase diagram is obtained; besides the paramagnetic phase, three distinct spin-glass phases appear. Three first-order critical frontiers are found and they all meet at a triple point; among such lines, two of them present discontinuities in the order parameters, but no latent heat, whereas the other one exhibits both discontinuities in the order parameters and a finite latent heat.Comment: 17 pages, 2 figures, submitted to Physica

Towards frame-like gauge invariant formulation for massive mixed symmetry bosonic fields. II. General Young tableau with two rows

In this paper we complete our construction of frame-like gauge invariant description for massive mixed symmetry tensor fields corresponding to arbitrary Young tableau with two rows started in [1]. We consider general massive theory in (A)dS spaces with arbitrary cosmological constant as well as all special limits which exist both in de Sitter and in anti-de Sitter spaces.Comment: 22 pages, 11 LaTeX picture

Gauge invariant formulation of massive totally symmetric fermionic fields in (A)dS space

Massive arbitrary spin totally symmetric free fermionic fields propagating in d-dimensional (Anti)-de Sitter space-time are investigated. Gauge invariant action and the corresponding gauge transformations for such fields are proposed. The results are formulated in terms of various mass parameters used in the literature as well as the lowest eigenvalues of the energy operator. We apply our results to a study of partial masslessness of fermionic fields in (A)dS(d), and in the case of d=4 confirm the conjecture made in the earlier literature.Comment: 14 pages, LaTeX -2e. v3: misprint in equation (2.24) corrected, footnotes 1,2,8,10 and references added, notation for the cosmological constant and operator of gauge transformation change

Toward frame-like gauge invariant formulation for massive mixed symmetry bosonic fields

In this paper, as a first step toward frame-like gauge invariant formulation for massive mixed symmetry bosonic fields, we consider mixed tensors, corresponding to Young tableau with two rows with k >= 2 boxes in the first row and only one box in the second one. We construct complete Lagrangian and gauge transformations describing massive particles in (anti) de Sitter space-time with arbitrary dimension d >= 4 and investigate all possible massless and partially massless limits.Comment: 18 pages, 9 LaTeX picture

Nonlinear Equations for Symmetric Massless Higher Spin Fields in (A)dSd(A)dS_d

Nonlinear field equations for totally symmetric bosonic massless fields of all spins in any dimension are presented.Comment: 19 pages, latex, no figures, v2 minor correction

Free geometric equations for higher spins

We show how allowing non-local terms in the field equations of symmetric tensors uncovers a neat geometry that naturally generalizes the Maxwell and Einstein cases. The end results can be related to multiple traces of the generalized Riemann curvatures R_{alpha_1 ... alpha_s; beta_1 > ... beta_s} introduced by de Wit and Freedman, divided by suitable powers of the D'Alembertian operator \Box. The conventional local equations can be recovered by a partial gauge fixing involving the trace of the gauge parameters Lambda_{alpha_1 ... alpha_{s-1}}, absent in the Fronsdal formulation. The same geometry underlies the fermionic equations, that, for all spins s+(1/2), can be linked via the operator (not hskip 1pt pr)/(\Box) to those of the spin-s bosons.Comment: References and comment added. Final version to appear in Physics Letters