Z(3)-symmetric effective theory for pure gauge QCD at high temperature

We review the construction and basic properties of a three-dimensional effective field theory for high-temperature SU(3) Yang-Mills theory, which respects its center symmetry and was introduced in hep-ph/0604100. We explain why the phase diagram of the new theory is expected to closely resemble the one of the full theory and argue that this implies that it is applicable down to considerably lower temperatures than the usual non-Z(3)-symmetric 3d effective theory EQCD.Comment: 4 pages, 1 figure; to appear in the proceedings of Strong and Electroweak Matter 200

Pi0 -> Gamma Gamma in Dense QCD

QCD superconductors in the color-flavor-locked (CFL) phase support light excitations (generalized pions) in the form of particle-particle or hole-hole excitations. We analyze the generalized process $\tilde\pi^0\to\tilde{\gamma}\tilde{\gamma}$ in the weak coupling limit and show that it is related to the recently suggested Wess-Zumino-Witten (WZW) term. In dense QCD, the radiative decay of the generalized pion is constrained by geometry and vanishes at large density.Comment: 7 pages, 1 figur

Dimensional reduction and a Z(3) symmetric model

We present first results from a numerical investigation of a Z(3) symmetric model based on dimensional reduction.Comment: Talk presented at XXI International Symposium on Lattice Field Theory lattice2003(Non-zero temperature and density

Numerical simulation of random paths with a curvature dependent action

We study an ensemble of closed random paths, embedded in R^3, with a curvature dependent action. Previous analytical results indicate that there is no crumpling transition for any finite value of the curvature coupling. Nevertheless, in a high statistics numerical simulation, we observe two different regimes for the specific heat separated by a rather smooth structure. The analysis of this fact warns us about the difficulties in the interpretation of numerical results obtained in cases where theoretical results are absent and a high statistics simulation is unreachable. This may be the case of random surfaces.Comment: 9 pages, LaTeX, 4 eps figures. Final version to appear in Mod. Phys. Lett.

Damping Rate of a Yukawa Fermion at Finite Temperature

The damping of a massless fermion coupled to a massless scalar particle at finite temperature is considered using the Braaten-Pisarski resummation technique. First the hard thermal loop diagrams of this theory are extracted and effective Green's functions are constructed. Using these effective Green's functions the damping rate of a soft Yukawa fermion is calculated. This rate provides the most simple example for the damping of a soft particle. To leading order it is proportional to $g^2T$, whereas the one of a hard fermion is of higher order.Comment: 5 pages, REVTEX, postscript figures appended, UGI-94-0

The deconfined phase near Tc and its decay into hadrons

We sketch an effective theory for the deconfined state of QCD near Tc. This relates the behavior of the expectation value of the Polyakov loop, and its two-point functions, to the pressure. Defining the ``mass'' of three and two gluon states from the imaginary and real parts of the Polyakov loop, while this ratio is 3:2 in perturbation theory, at Tc it is 3:1. We also discuss the decay of the deconfined state into hadrons.Comment: 4 pages, no figures, Contribution to the Proceedings of "Quark Matter 2002", Nantes, France, 18-24 Jul 200

Replacement of glass-former B2O3 by GeO2 in an amorphous host evidenced by optical methods

Two completely different glass-host matrices containing lead, i.e. borate and germanate glasses doped with erbium were studied. The replacement of glass-former B2O3 by GeO2 in an amorphous host was evidenced by optical methods. The luminescence decay from the⁴I13/2 upper laser state of Er³⁺ ions is relatively short, whereas the up-converted emission signal is reduced definitely in borate glass containing lead due to its high B-O stretching vibrations. The results indicate that germanate glasses containing lead are promising for near-infrared luminescence and up-conversion applications