Gluon Bremsstrahlung in Weakly-Coupled Plasmas

I report on some theoretical progress concerning the calculation of gluon bremsstrahlung for very high energy particles crossing a weakly-coupled quark-gluon plasma. (i) I advertise that two of the several formalisms used to study this problem, the BDMPS-Zakharov formalism and the AMY formalism (the latter used only for infinite, uniform media), can be made equivalent when appropriately formulated. (ii) A standard technique to simplify calculations is to expand in inverse powers of logarithms $\ln(E/T)$. I give an example where such expansions are found to work well for $\omega/T \gtrsim 10$ where $\omega$ is the bremsstrahlung gluon energy. (iii) Finally, I report on perturbative calculations of $\hat q$.Comment: 4 pages, 2 figures - To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennessee [change from v2: minor changes for publication

Cumulative Step-size Adaptation on Linear Functions

The CSA-ES is an Evolution Strategy with Cumulative Step size Adaptation, where the step size is adapted measuring the length of a so-called cumulative path. The cumulative path is a combination of the previous steps realized by the algorithm, where the importance of each step decreases with time. This article studies the CSA-ES on composites of strictly increasing functions with affine linear functions through the investigation of its underlying Markov chains. Rigorous results on the change and the variation of the step size are derived with and without cumulation. The step-size diverges geometrically fast in most cases. Furthermore, the influence of the cumulation parameter is studied.Comment: arXiv admin note: substantial text overlap with arXiv:1206.120

Cumulative Step-size Adaptation on Linear Functions: Technical Report

The CSA-ES is an Evolution Strategy with Cumulative Step size Adaptation, where the step size is adapted measuring the length of a so-called cumulative path. The cumulative path is a combination of the previous steps realized by the algorithm, where the importance of each step decreases with time. This article studies the CSA-ES on composites of strictly increasing with affine linear functions through the investigation of its underlying Markov chains. Rigorous results on the change and the variation of the step size are derived with and without cumulation. The step-size diverges geometrically fast in most cases. Furthermore, the influence of the cumulation parameter is studied.Comment: Parallel Problem Solving From Nature (2012

A Proof of the Isoenergetic KAM-Theorem from the “Ordinary” One

A proof is given of the isoenergetic KAM-theorem for Hamiltonian systems, using the “ordinary” KAM-theorem and a transversality argument.

Results from the NEMO 3 experiment

The aim of the NEMO 3 experiment is the search for neutrinoless double beta decay and precise measurement of two-neutrino double beta decay of several isotopes. The experiment has been taking data since 2003. Since no evidence for neutrinoless double beta decay of Mo100 and Se82 has been found, a 90% C.L. lower limit on the half-life of this process and corresponding upper limit on the effective Majorana neutrino mass are derived. The data are also interpreted in terms of alternative models, such as weak right-handed currents or Majoron emission. In addition, NEMO 3 has performed precision measurements of the two-neutrino double beta decay for seven different isotopes. The most recent experimental results of NEMO 3 are presented in this paper.Comment: 5 pages, 2 tables, talk at the 10th ICATPP Conference (Como, Italy, 8 - 12 October 2007

Visualizing Color Plasma Instabilities

I discuss recent advances in the understanding of non-equilibrium gauge field dynamics in plasmas which have particle distributions which are locally anisotropic in momentum space. In contrast to locally isotropic plasmas such anisotropic plasmas have a spectrum of soft unstable modes which are characterized by exponential growth of transverse (chromo)-magnetic fields at short times. The long-time behavior of such instabilities depends on whether or not the gauge group is abelian or non-abelian. I will report on recent numerical simulations which attempt to determine the long-time behavior of an anisotropic non-abelian plasma within hard-loop effective theory. For novelty I will present an interesting method for visualizing the time-dependence of SU(2) gauge field configurations produced during our numerical simulations.Comment: 10 pages, 5 figures. Contribution to Proceedings of Workshop on Quark-Gluon-Plasma Thermalization, Vienna, Austria, Aug 10-12. For full resolution images see http://www.fias.uni-frankfurt.de/home/strickland/instability

Autodocumentation

Automated documentation systems with expanded capabilities for reusing existing programs are considered by allowing a relatively inexpensive determination of program capabilities. A theoretical approach to such a system is proposed. Tree structure variations are examined, along with assignment statements, conditional branches, loops, and an automated analyzer

A new Truncated Fourier Transform algorithm

Truncated Fourier Transforms (TFTs), first introduced by Van der Hoeven, refer to a family of algorithms that attempt to smooth "jumps" in complexity exhibited by FFT algorithms. We present an in-place TFT whose time complexity, measured in terms of ring operations, is comparable to existing not-in-place TFT methods. We also describe a transformation that maps between two families of TFT algorithms that use different sets of evaluation points.Comment: 8 pages, submitted to the 38th International Symposium on Symbolic and Algebraic Computation (ISSAC 2013

Bose-Einstein condensates in `giant' toroidal magnetic traps

The experimental realisation of gaseous Bose-Einstein condensation (BEC) in 1995 sparked considerable interest in this intriguing quantum fluid. Here we report on progress towards the development of an 87Rb BEC experiment in a large (~10cm diameter) toroidal storage ring. A BEC will be formed at a localised region within the toroidal magnetic trap, from whence it can be launched around the torus. The benefits of the system are many-fold, as it should readily enable detailed investigations of persistent currents, Josephson effects, phase fluctuations and high-precision Sagnac or gravitational interferometry.Comment: 5 pages, 3 figures (Figs. 1 and 2 now work

On examples of difference operators for {0,1}\{0,1\}-valued functions over finite sets

Recently V.I.Arnold have formulated a geometrical concept of monads and apply it to the study of difference operators on the sets of $\{0,1\}$-valued sequences of length $n$. In the present note we show particular examples of these monads and indicate one question arising here