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

Thermodynamics of Deconfined QCD at Small and Large Chemical Potential

We present large $N_f$ QCD/QED as a test bed for improved pressure calculations, show how to apply the hints obtained on optimized renormalization scales at large $N_f$ to finite $N_f=2$, and compare the results to recent lattice data.Comment: 5 pages, to appear in the proceedings of SEWM 2004, Helsinki, 16-19 June 200

Broken boost invariance in the Glasma via finite nuclei thickness

We simulate the creation and evolution of non-boost-invariant Glasma in the early stages of heavy ion collisions within the color glass condensate framework. This is accomplished by extending the McLerran-Venugopalan model to include a parameter for the Lorentz-contracted but finite width of the nucleus in the beam direction. We determine the rapidity profile of the Glasma energy density, which shows deviations from the boost-invariant result. Varying the parameters both broad and narrow profiles can be produced. We compare our results to experimental data from RHIC and find surprising agreement.Comment: 6 pages, 4 figure

Rapidity profiles from 3+1D Glasma simulations with finite longitudinal thickness

We present our progress on simulating the Glasma in the early stages of heavy ion collisions in a non-boost-invariant setting. Our approach allows us to describe colliding nuclei with finite longitudinal width by extending the McLerran-Venugopalan model to include a parameter for the Lorentz-contracted but finite extent of the nucleus in the beam direction. We determine the rapidity profile of the Glasma energy density, which shows strong deviations from the boost invariant result. Both broad and narrow profiles can be produced by varying the initial conditions. We find reasonable agreement when we compare the results to rapidity profiles of measured pion multiplicities from RHIC.Comment: 5+1 pages, 2 figures, prepared for Proceedings of the European Physical Society Conference on High Energy Physics (EPS-HEP) 201

Anomalous specific heat in ultradegenerate QED and QCD

We discuss the origin of the anomalous $T\ln T^{-1}$ behavior of the low-temperature entropy and specific heat in ultradegenerate QED and QCD and report on a recent calculation which is complete to leading order in the coupling and which contains an infinite series of anomalous terms involving also fractional powers in $T$. This result involves dynamical hard-dense-loop resummation and interpolates between Debye screening effects at larger temperatures and non-Fermi-liquid behavior from only dynamically screened magnetic fields at low temperature.Comment: 5 pages, 3 figures, contribution to the Proceedings of Strong and Electroweak Matter 2004 (SEWM04), Helsinki, Finland, 16-19 Jun 200

Yoctosecond metrology through HBT correlations from a quark-gluon plasma

Expansion dynamics at the yoctosecond timescale affect the evolution of the quark gluon plasma (QGP) created in heavy ion collisions. We show how these dynamics are accessible through Hanbury Brown and Twiss (HBT) intensity interferometry of direct photons emitted from the interior of the QGP. A detector placed close to the beam axis is particularly sensitive to early polar momentum anisotropies of the QGP. Observing a modification of the HBT signal at the proposed FoCal detector of the LHC ALICE experiment would allow to measure the isotropization time of the plasma and could provide first experimental evidence for photon double pulses at the yoctosecond timescale.Comment: 5 pages, 3 figure

Study of the gluon propagator in the large-N_f limit at finite temperature and chemical potential for weak and strong couplings

At finite temperature and chemical potential, the leading-order (hard-thermal-loop) contributions to the gauge-boson propagator lead to momentum-dependent thermal masses for propagating quasiparticles as well as dynamical screening and Landau damping effects. We compare the hard-thermal-loop propagator with the complete large-N_f gluon propagator, for which the usually subleading contributions, such as a finite width of quasiparticles, can be studied at nonperturbatively large effective coupling. We also study quantitatively the effect of Friedel oscillations in low-temperature electrostatic screening.Comment: REVTEX, 23 pages, 20 figure

Non-Fermi-Liquid Specific Heat of Normal Degenerate Quark Matter

We compute the low-temperature behavior of the specific heat of normal (non-color-superconducting) degenerate quark matter as well as that of an ultradegenerate electron gas. Long-range magnetic interactions lead to non-Fermi-liquid behavior with an anomalous leading $T\ln T^{-1}$ term. Depending on the thermodynamic potential used as starting point, this effect appears as a consequence of the logarithmic singularity in the fermion self-energy at the Fermi surface or directly as a contribution from the only weakly screened quasistatic magnetic gauge bosons. We show that a calculation of Boyanovsky and de Vega claiming the absence of a leading $T\ln T^{-1}$ term missed it by omitting vector boson contributions to the internal energy. Using a formulation which collects all nonanalytic contributions in bosonic ring diagrams, we systematically calculate corrections beyond the well-known leading-log approximation. The higher-order terms of the low-temperature expansion turn out to also involve fractional powers $T^{(3+2n)/3}$ and we explicitly determine their coefficients up to and including order $T^{7/3}$ as well as the subsequent logarithmically enhanced term $T^3 \ln (c/T)$. We derive also a hard-dense-loop resummed expression which contains the infinite series of anomalous terms to leading order in the coupling and which we evaluate numerically. At low temperatures, the resulting deviation of the specific heat from its value in naive perturbation theory is significant in the case of strongly coupled normal quark matter and thus of potential relevance for the cooling rates of (proto-)neutron stars with a quark matter component.Comment: REVTEX, 26 pages, 5 postscript figures. v3: new chapter added which performs a complete hard-dense-loop resummation, covering the infinite series of anomalous terms and extending the range of applicability to all T << m