ar X iv : c on d - m at / 9 90 83 26 v 3 2 N ov 1 99 9 Gaudin Hypothesis for the XY Z Spin Chain

ar X iv : c on d - m at / 9 90 83 26 v 1 2 4 A ug 1 99 9 Gaudin Hypothesis for the XY Z Spin Chain

The XY Z spin chain is considered in the framework of the generalized algebraic Bethe ansatz developed by Takhtajan and Faddeev. The sum of norms of the Bethe vectors is computed and expressed in the form of a Jacobian. This result corresponds to the Gaudin hypothesis for the XY Z spin chain.

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

v 2 4 S ep 1 99 9 Gaudin Hypothesis for the XY Z Spin Chain

The XY Z spin chain is considered in the framework of the generalized algebraic Bethe ansatz developed by Takhtajan and Faddeev. The sum of norms of the Bethe vectors is computed and expressed in the form of a Jacobian. This result corresponds to the Gaudin hypothesis for the XY Z spin chain.

ar X iv : c on d - m at / 9 51 10 29 v 2 1 3 N ov 1 99 5 Spin gap in CaV 4 O 9 : a large S approach Marc

We study the stability of the 4-site plaquette order in a model recently introduced by Katoh and Imada to explain the spin gap observed in CaV4O9. We show that all relevant types of order (4-site plaquette, dimerized, Néel) can be described within the framework of Schwinger boson mean field theory, and we make predictions regarding their relative stability. The results are compared to exact dia...

ar X iv : c on d - m at / 9 90 64 41 v 1 3 0 Ju n 19 99 FINITE TEMPERATURE TRANSPORT IN INTEGRABLE QUANTUM MANY BODY SYSTEMS

Recent developments in the analysis of finite temperature dissipationless transport in inte-grable quantum many body problems are presented. In particular, we will discuss: (i) the role played by the conservation laws in systems as the spin 1/2 Heisenberg chain and the one-dimensional Hubbard model, (ii) exact results obtained using the Bethe ansatz method on the long time decay of current corr...