[1] Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
[2] Univ Alberta, Dept Phys, Edmonton, AB, Canada
[3] Univ Innsbruck, IQOQI, A-6020 Innsbruck, Austria
[4] Univ Innsbruck, Inst Theoret Phys, A-6020 Innsbruck, Austria
[5] Univ Strasbourg, ISIS, UMR 7006, Strasbourg, France
[6] Univ Strasbourg, IPCMS, UMR 7504, Strasbourg, France
[7] CNRS, Strasbourg, France