Viscosities in the Gluon-Plasma within a Quasiparticle Model

A phenomenological quasiparticle model, featuring dynamically generated self-energies of excitation modes, successfully describes lattice QCD results relevant for the QCD equation of state and related quantities both at zero and non-zero net baryon density. Here, this model is extended to study bulk and shear viscosities of the gluon-plasma within an effective kinetic theory approach. In this way, the compatibility of the employed quasiparticle ansatz with the apparent low viscosities of the strongly coupled deconfined gluonic medium is shown.Comment: 4 pages, 1 figure. To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennessee, US

Shear and bulk viscosities of the gluon plasma in a quasiparticle description

Shear and bulk viscosities of deconfined gluonic matter are investigated within an effective kinetic theory by describing the strongly interacting medium phenomenologically in terms of quasiparticle excitations with medium-dependent self-energies. We show that the resulting transport coefficients reproduce the parametric dependencies on temperature and coupling obtained in perturbative QCD at large temperatures and small running coupling. The extrapolation into the non-perturbative regime results in a decreasing specific shear viscosity with decreasing temperature, exhibiting a minimum in the vicinity of the deconfinement transition, while the specific bulk viscosity is sizeable in this region falling off rapidly with increasing temperature. The temperature dependence of specific shear and bulk viscosities found within this quasiparticle description of the pure gluon plasma is in agreement with available lattice QCD results.Comment: Sep 2011. 24pp. 6 figures. revised journal versio

Transport Coefficients in Gluodynamics: From Weak Coupling towards the Deconfinement Transition

We study the ratio of bulk to shear viscosity in gluodynamics within a phenomenological quasiparticle model. We show that at large temperatures this ratio exhibits a quadratic dependence on the conformality measure as known from weak coupling perturbative QCD. In the region of the deconfinement transition, however, this dependence becomes linear as known from specific strongly coupled theories. The onset of the strong coupling behavior is located near the maximum of the scaled interaction measure. This qualitative behavior of the viscosity ratio is rather insensitive to details of the equation of state.Comment: Oct 2011. 3 pages. 3 figures. Contribution to the proceedings of the 19th Particles and Nuclei International Conference (PANIC11

Fluctuation Superconductivity in Mesoscopic Aluminum Rings

Fluctuations are important near phase transitions, where they can be difficult to describe quantitatively. Superconductivity in mesoscopic rings is particularly intriguing because the critical temperature is an oscillatory function of magnetic field. There is an exact theory for thermal fluctuations in one-dimensional superconducting rings, which are therefore expected to be an excellent model system. We measure the susceptibility of many rings, one ring at a time, using a scanning SQUID that can isolate magnetic signals from seven orders of magnitude larger background applied flux. We find that the fluctuation theory describes the results and that a single parameter characterizes the ways in which the fluctuations are especially important at magnetic fields where the critical temperature is suppressed.Comment: Reprinted with permission from AAA

Edge-Magnetoplasmon Wave-Packet Revivals in the Quantum Hall Effect

The quantum Hall effect is necessarily accompanied by low-energy excitations localized at the edge of a two-dimensional electron system. For the case of electrons interacting via the long-range Coulomb interaction, these excitations are edge magnetoplasmons. We address the time evolution of localized edge-magnetoplasmon wave packets. On short times the wave packets move along the edge with classical E cross B drift. We show that on longer times the wave packets can have properties similar to those of the Rydberg wave packets that are produced in atoms using short-pulsed lasers. In particular, we show that edge-magnetoplasmon wave packets can exhibit periodic revivals in which a dispersed wave packet reassembles into a localized one. We propose the study of edge-magnetoplasmon wave packets as a tool to investigate dynamical properties of integer and fractional quantum-Hall edges. Various scenarios are discussed for preparing the initial wave packet and for detecting it at a later time. We comment on the importance of magnetoplasmon-phonon coupling and on quantum and thermal fluctuations.Comment: 18 pages, RevTex, 7 figures and 2 tables included, Fig. 5 was originally 3Mbyte and had to be bitmapped for submission to archive; in the process it acquired distracting artifacts, to upload the better version, see http://physics.indiana.edu/~uli/publ/projects.htm

Die Bedeutung von Factory Outlets aus der Sicht von Herstellern und Kunden

Der Fabrikverkauf hat in Deutschland eine lange Tradition. Schon seit vielen Jahrzehnten bieten Hersteller am Fertigungsstandort überschüssige Produktion oder leicht fehlerhafte Ware zu niedrigen Preisen feil. Neu ist indes die heftige Diskussion über dieses Absatzkonzept. Im Mittelpunkt der öffentlichen Auseinandersetzung stehen die Bedenken des Handels hinsichtlich der Planung großflächiger Factory Outlet Center. Dieser befürchtet, daß hierdurch Kaufkraft aus dem innerstädtischen Einzelhandel abgezogen wird und damit dort Arbeitsplätze verloren gehen. Auch in den herkömmlichen Fabrikverkaufsläden tut sich etwas. Durch die Verbreitung sogenannter Schnäppchenführer haben viele Factory Outlets in Deutschland überregionale Beachtung erfahren. Da diesen aber bislang wenig Aufmerksamkeit in der wissenschaftlichen Literatur geschenkt wurde, besteht Unklarheit über die Beurteilung vorhandener Fabrikverkaufsstellen seitens der Betreiber sowie die zukünftige Entwicklung dieses Absatzkonzeptes. Auch hinsichtlich der Kunden dieser Vertriebsform, der Motive für den Kauf ab Werk sowie der Bewertung von Factory Outlets durch die Konsumenten gibt es noch Wissenslücken. Zur Versachlichung der Diskussion erscheint es daher geboten, diese Aspekte näher zu beleuchten. Im Anschluß an eine Erläuterung der Begriffe Factory Outlet und Factory Outlet Center (FOC) werden Entwicklungstrends auf seiten des Handels sowie der Konsumenten aufgezeigt, die die Bedeutung des Fabrikverkaufs als Absatzkonzept beeinflussen. In Kapitel 4 folgt die Darstellung der Ergebnisse einer empirischen Untersuchung bei Geschäftsführern von Fabrikverkaufsstellen sowie deren Kunden, aus der Empfehlungen für die Betreiber von Factory Outlets sowie den Fachhandel abgeleitet werden

Civil-military relations and sexual assault

The Bureau of Justice Statistics' Criminal Victimization Survey reported that there were 284,350 rapes or sexual assaults in the United States in 2014. In the same year, the Department of Defense (DOD) Sexual Assault Prevention and Response Office (SAPRO) estimated that 18,900 sexual assaults occurred in the military. In recent years, Congress has been increasing pressure on the military to improve sexual assault prevention and response; some efforts to resolve the sexual assault problem in the military have included proposals to alter the military justice system to resemble its civilian counterpart. Yet, as the numbers suggest, the civilian justice system may not be doing such a good job either. Civil-military relations revolve around who controls what. This thesis addresses the role of civil-military relations in regard to sexual assault prevention and response. Through official statistics, documents from the state of California and the Department of Defense, scholarly research, and reports from the media, this paper describes the experience of the victim as he or she navigates through either system. The comparison of the systems side by side reveals that, if the civilian and military communities work together to capitalize on learning from each other, real progress can occur in serving victims of sexual assault in both systems. The power struggle in civil-military relations, over who controls what, tends to distract from the root issue of serving victims of sexual assault. The focus must shift from Who is doing a worse job? to How can both systems learn from the other to improve and best serve the victims of these horrible crimes?http://archive.org/details/civilmilitaryrel1094550482Civilian, United States NavyApproved for public release; distribution is unlimited

Degrees of Freedom of the Quark Gluon Plasma, tested by Heavy Mesons

Heavy quarks (charm and bottoms) are one of the few probes which are sensitive to the degrees of freedom of a Quark Gluon Plasma (QGP), which cannot be revealed by lattice gauge calculations in equilibrium. Due to the rapid expansion of the QGP energetic heavy quarks do not come to an equilibrium with the QGP. Their energy loss during the propagation through the QGP medium depends strongly on the modelling of the interaction of the heavy quarks with the QGP quarks and gluons, i.e. on the assuption of the degrees of freedom of the plasma. Here we compare the results of different models, the pQCD based Monte-Carlo (MC@sHQ), the Dynamical Quasi Particle Model (DQPM) and the effective mass approach, for the drag force in a thermalized QGP and discuss the sensitivity of heavy quark energy loss on the properties of the QGP as well as on non-equilibrium dynamicsComment: proceedings symposion "New Horizons" Makutsi, South Africa, Nov 201