ar X iv : c on d - m at / 9 90 90 44 v 1 3 S ep 1 99 9 Systematic low temperature expansion in Ginzburg - Landau model

ar X iv : c on d - m at / 9 60 90 54 v 1 5 S ep 1 99 6 Cumulant Expansions and the Spin - Boson Problem ∗

The dynamics of the dissipative two-level system at zero temperature is studied using three different cumulant expansion techniques. The relative merits and drawbacks of each technique are discussed. It is found that a new technique, the non-crossing cumulant expansion, appears to embody the virtues of the more standard cumulant methods. PACS-number(s): 05.30.-d, 05.40.+j, 72.15.Qm submitted to...

ar X iv : m at h - ph / 9 90 90 25 v 1 2 1 Se p 19 99 The symmetries of the Manton superconductivity model

The symmetries and conserved quantities of Manton's modified superconductiv-ity model with non-relativistic Maxwell-Chern-Simons dynamics (also related to the Quan-tized Hall Effect) are obtained in the " Kaluza-Klein type " framework of Duval et al. 1. Introduction Recently [1], Manton proposed a modified version of the Landau-Ginzburg theory of superconductivity. His equations, defined on (2 ...

ar X iv : h ep - l at / 9 90 90 23 v 1 3 S ep 1 99 9 1 Potential between external monopole and antimonopole in SU ( 2 ) lattice

We present the results of a study of the free energy of a monopole pair in pure SU(2) theory at finite temperature , both below and above the deconfinement transition. We find a Yukawa potential between monopoles in both phases. At low temperature, the screening mass is compatible with the lightest glueball mass. At high temperature, we observe an increased screening mass with no apparent disco...

ar X iv : c on d - m at / 9 60 90 73 v 1 7 S ep 1 99 6 Determination of Exchange Parameters for CaV 4 O

Magnetic susceptibility measured for CaV4O9 is analyzed by a method with high temperature expansion. The analysis is consistent with the g-value which is close to 2 and is observed by an ESR experiment. Four exchange parameters in a two-dimensional Heisenberg model are determined to represent CaV4O9. All the exchange parameters are about 500 K and strongly frustrated. The observed spin gap orig...

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