0 60 40 65 v 2 2 3 M ay 2 00 6 First - order transitions for some generalized XY models

2 00 6 First - order transitions for some generalized XY models

In this note we demonstrate the occurrence of first-order transitions in temperature for some recently introduced generalized XY models, and also 1 point out the connection between them and annealed site-diluted (lattice-gas) continuous-spin models.

0 50 60 66 v 2 3 M ay 2 00 6 Existence of Spontaneous Pair Creation

1 5 M ay 2 00 1 Exact diagonalization of the S = 1 / 2 XY ferromagnet on finite bcc lattices to estimate T = 0 properties on the infinite lattice

In this paper finite bcc lattices are defined by a triple of vectors in two different ways upper triangular lattice form and compact form. In Appendix A are lists of some 260 distinct and useful bcc lattices of 9 to 32 vertices. The energy and magnetization of the S = 1/2 XY ferromagnet have been computed on these bcc lattices in the lowest states for Sz = 0, 1/2, 1 and 3/2. These data are stud...

ar X iv : h ep - p h / 03 05 27 4 v 1 2 6 M ay 2 00 3 Impact of U e 3 on Neutrino Models 1 Morimitsu Tanimoto

We have discussed the impact of U e3 on the model of the neutrino mass matrix. In order to get the small U e3 , some flavor symmetry is required. Typical two models are investigated. The first one is the model in which the bi-maximal mixing is realized at the symmetric limit. The second one is the texture zeros of the neutrino mass matrix.

ar X iv : m at h - ph / 0 31 20 41 v 2 7 M ay 2 00 4 PARTITION FUNCTION ZEROS AT FIRST - ORDER PHASE TRANSITIONS : PIROGOV - SINAI THEORY

This paper is a continuation of our previous analysis [2] of partition functions zeros in models with first-order phase transitions and periodic boundary conditions. Here it is shown that the assumptions under which the results of [2] were established are satisfied by a large class of lattice models. These models are characterized by two basic properties: The existence of only a finite number o...