Resummed one-loop gluonic contributions to the color superconducting color charge density vanish

It is shown that gluonic corrections to the tadpole diagrams vanish in the 2SC and CFL phases at the order where one might have expected NLO corrections. This implies that the gluonic part of the color charge density is negligible at the order of our computation. This statement remains true after inclusion of the gluon vertex correction and contributions from Nambu-Goldstone bosons.Comment: 9 pages, 3 figures, REVTeX4; title modified, comments about gauge independence added, accepted for publication in Phys. Rev.

Fermionic dispersion relations in ultradegenerate relativistic plasmas beyond leading logarithmic order

We determine the dispersion relations of fermionic quasiparticles in ultradegenerate plasmas by a complete evaluation of the on-shell hard-dense-loop-resummed one-loop fermion self energy for momenta of the order of the Fermi momentum and above. In the case of zero temperature, we calculate the nonanalytic terms in the vicinity of the Fermi surface beyond the known logarithmic approximation, which turn out to involve fractional higher powers in the energy variable. For nonzero temperature (but much smaller than the chemical potential), we obtain the analogous expansion in closed form, which is then analytic but involves polylogarithms. These expansions are compared with a full numerical evaluation of the resulting group velocities and damping coefficients.Comment: 9 pages, 2 figures, REVTeX4, v2: minor improvement

The pressure of deconfined QCD for all temperatures and quark chemical potentials

A new method for the evaluation of the perturbative expansion of the QCD pressure is presented which is valid for all temperatures and quark chemical potentials in the deconfined phase, and worked out up to and including order g^4. This new approach unifies several distinct perturbative approaches to the equation of state, and agrees with dimensional reduction, HDL and HTL resummation schemes, and the zero-temperature result in their respective ranges of validity.Comment: 4 pages, 5 figures, to appear in the proceedings of Strong and Electroweak Matter 2006 (SEWM), BNL, May 200

Supercurrents in color-superconducting quark matter

We review the basic properties of the currCFL-K^0 phase in dense quark matter. At asymptotically large densities, three-flavor quark matter is in the color-flavor locked (CFL) state. The currCFL-K^0 state is a way to respond to ``stress'' on the quark Cooper pairing, imposed at more moderate densities by the strange quark mass and the conditions of electric and color neutrality. We show how a kaon supercurrent is incorporated in a purely fermionic formalism, and show that the net current vanishes due to cancellation of fermion and charge-conjugate fermion contributions.Comment: 8 pages, to appear in the proceedings of "Strong and ElectroWeak Matter 2008", Amsterdam, the Netherlands, 26-29 August 200

HICFD – Highly Efficient Implementation of CFD Codes for HPC Many-Core Architectures

The objective of the German BMBF research project Highly Efficient Implementation of CFD Codes for HPC Many-Core Architectures (HICFD) is to develop new methods and tools for the analysis and optimization of the performance of parallel computational fluid dynamics (CFD) codes on high performance computer systems with many-core processors. In the work packages of the project it is investigated how the performance of parallel CFD codes written in C can be increased by the optimal use of all parallelism levels. On the highest level MPI is utilized. Furthermore, on the level of the many-core architecture, highly scaling, hybrid OpenMP/MPI methods are implemented. On the level of the processor cores the parallel SIMD units provided by modern CPUs are exploited

Aspects of cold dense quark matter

Zsfassung in dt. SpracheDer Gegenstand dieser Dissertation ist Quarkmaterie bei hoher Dichte und (vergleichsweise) niedriger Temperatur. Materie in diesem Zustand findet sich in der Natur möglicherweise im Inneren von (manchen) Neutronensternen. In dieser Dissertation werden die spezifische Wärme und die Quark-Selbstenergie in normaler Quarkmaterie ausführlich diskutiert. Eine Diskrepanz zwischen früheren Arbeiten zur spezifischen Wärme wird aufgeklärt. Ausserdem werden in der vorliegenden Arbeit systematisch höhere Korrekturen zu den bereits bekannten führenden Termen berechnet. Bei hinreichend tiefen Temperaturen wird Quarkmaterie farbsupraleitend. Es wird ein formaler Beweis gegeben, dass die fermionischen Quasiteilchen- Dispersionsrelationen in einem Farbsupraleiter eichunabhängig sind. Weiters wird der Erwartungswert des Gluonfeldes in einem Farbsupraleiter in führender Ordnung berechnet.This thesis is devoted to properties of quark matter at high density and (comparatively) low temperature. In nature matter under these conditions can possibly be found in the interior of (some) neutron stars. In this thesis the specific heat and the quark self energy in normal quark matter are discussed in detail. A discrepancy between earlier papers on the specific heat is resolved. Moreover higher order corrections to the known leading order terms are computed in this thesis in a systematic manner. At sufficiently low temperatures quark matter is a color superconductor. A formal proof is given that the fermionic quasiparticle dispersion relations in a color superconductor are gauge independent. Moreover the expectation value of the gluon field in a color superconductor is computed at leading order.11

On the Lévy-Khinchin decomposition of generating functionals

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