Thermalization and the chromo-Weibel instability

Despite the apparent success of ideal hydrodynamics in describing the elliptic flow data which have been produced at Brookhaven National Lab's Relativistic Heavy Ion Collider, one lingering question remains: is the use of ideal hydrodynamics at times t < 1 fm/c justified? In order to justify its use a method for rapidly producing isotropic thermal matter at RHIC energies is required. One of the chief obstacles to early isotropization/thermalization is the rapid longitudinal expansion of the matter during the earliest times after the initial nuclear impact. As a result of this expansion the parton distribution functions become locally anisotropic in momentum space. In contrast to locally isotropic plasmas anisotropic plasmas have a spectrum of soft unstable modes which are characterized by exponential growth of transverse chromo-magnetic/-electric fields at short times. This instability is the QCD analogue of the Weibel instability of QED. Parametrically the chromo-Weibel instability provides the fastest method for generation of soft background fields and dominates the short-time dynamics of the system.Comment: 8 pages, 4 figures, Invited plenary talk given at the 19th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions: Quark Matter 2006 (QM 2006), Shanghai, China, 14-20 Nov 200

Colour Coherence in Photon Induced Reactions

Colour coherence in hard photoproduction is considered using the Monte Carlo event generators PYTHIA and HERWIG. Significant effects in the parton shower are found using multijet observables for direct and resolved photon induced reactions. The particle flow in the interjet region of direct processes shows a strong influence of string fragmentation effects.Comment: 6 pages, LaTeX, 6 eps figures included, to appear in the proceedings of the workshop "Future Physics at HERA

Lines in quantum grassmannians

We study quantum lines in quantum grassmannians and prove that there are only finitely many corresponding to lines in usual grassmannians fixed by a maximal torus

The QCD trace anomaly

In this brief report we compare the predictions of a recent next-to-next-to-leading order hard-thermal-loop perturbation theory (HTLpt) calculation of the QCD trace anomaly to available lattice data. We focus on the trace anomaly scaled by T^2 in two cases: N_f=0 and N_f=3. When using the canonical value of mu = 2 pi T for the renormalization scale, we find that for Yang-Mills theory (N_f=0) agreement between HTLpt and lattice data for the T^2-scaled trace anomaly begins at temperatures on the order of 8 T_c while when including quarks (N_f=3) agreement begins already at temperatures above 2 T_c. In both cases we find that at very high temperatures the T^2-scaled trace anomaly increases with temperature in accordance with the predictions of HTLpt.Comment: 12 pages, 4 figures; v3 published versio

Hard-thermal-loop QCD Thermodynamics

Naively resummed perturbative approximations to the thermodynamic functions of QCD do not converge at phenomenologically relevant temperatures. Here we review recent results of a three-loop hard-thermal-loop perturbation theory calculation of the thermodynamic functions of a quark-gluon plasma for general N_c and N_f. We show comparisons of our recent results with lattice data from both the hotQCD and Wuppertal-Budapest groups. We demonstrate that the three-loop hard-thermal-loop perturbation result for QCD thermodynamics agrees with lattice data down to temperatures T ~ 2 T_c.Comment: 8 pages, 2 figures; Talk given at the Symposium on "High Energy Strong Interactions", Aug. 9-13, 2010, Yukawa Institute for Theoretical Physics, Kyoto, Japan; submitted to Prog. Theor. Phys. Supp

The Reisner–Stanley system and equivariant cohomology for a class of wonderful varieties

AbstractIn this paper we are going to determine the equivariant cohomology of the wonderful compactification of a symmetric variety G/H and its equivariant ring of conditions under the assumption that rk(H)+rk(G/H)=rk(G)

Improving the Professional Capacity of Campus Administrators at a Multi-Campus College

The institutional knowledge gap for campus administrators (CAs) across a multi-campus college is the Problem of Practice (PoP) to be addressed in this Organizational Improvement Plan (OIP). A multi-campus college has initiated a new professional development review (PDR) for CAs to improve professional excellence across the organization. The PDR launched to identify professional development needs for college managers, to improve operational efficiency, and to help the college achieve its strategic goals. CAs shoulder the responsibility for the campus-level implementation of college policies and procedures which necessitates a firm understanding of college operations and effective leadership and management skills. When there are knowledge gaps, there is a risk of inconsistent application of college directives across the campuses. Creating learning opportunities for both new and current CAs would lead to strong PDR outcomes, improved professional capacity, equitable access to learning, and consistent campus operations. The principles of social network theory in conjunction with team and transformational leadership will guide the development of solutions to address this PoP. Developing both formal and informal learning opportunities can create an organization that supports and grows the professional capacity of CA team. Therefore, an onboarding program coupled with a networked learning community is proposed to increase professional development opportunities for CAs. The implementation of the change initiative at the college will be guided by the change path model and the plan-do-study-act cycle. The outcomes of this OIP can be extended to other college department managers and other multi-campus educational institutions