ar X iv : c on d - m at / 9 60 30 88 v 1 1 2 M ar 1 99 6 Finite temperature mobility of a particle coupled to a fermion environment

ar X iv : c on d - m at / 9 60 31 90 v 1 2 9 M ar 1 99 6 The Four - Dimensional XY Spin Glass

ar X iv : c on d - m at / 9 50 60 18 v 1 5 J un 1 99 5 Hartree - Fock ground state of the composite fermion metal

Within the Hartree-Fock approximation the ground state of the composite fermion metal is found. We observe that the single-particle energy spectrum is dominated by the logarithmic interaction exchange term which leads to an infinite jump of the singleparticle energy at the Fermi momentum. It is shown that the Hartree-Fock result brings no corrections to the RPA Fermi velocity.

ar X iv : c on d - m at / 9 70 30 28 v 1 3 M ar 1 99 7 In - plane optical response of Bi 2 Sr 2 CuO 6

We report on infrared reflectivity measurements of the ab-plane response of superconducting Bi2Sr2CuO6 single crystals. The frequency dependent conductivity has a maximum near 500 cm at room temperature, which shifts to lower frequency and merges with a Drude peak below 100 K. We attribute the unusual behavior of the mid-infrared conductivity to low frequency transitions between electronic band...

ar X iv : c on d - m at / 9 60 30 23 v 1 4 M ar 1 99 6 Few interacting particles in a random potential

We study the localization length of few interacting particles in a random potential. Concentrating on the case of three particles we show that their localization length is strongly enhanced comparing to the enhancement for two interacting particles.

ar X iv : g r - qc / 9 60 20 21 v 2 1 7 M ar 1 99 6 1 Some remarks on finite - gap solutions of the Ernst equation

It is explicitly shown that the class of algebro-geometrical (finite-gap) solutions of the Ernst equation constructed several years ago in [1] contains the solutions recently constructed by R.Meinel and G.Neugebauer [2] as a subset.