ar X iv : c on d - m at / 9 90 11 70 v 1 1 8 Ja n 19 99 Spin Relaxation of Conduction Electrons

ar X iv : c on d - m at / 9 51 21 60 v 1 2 2 D ec 1 99 5 Spin - reflection positivity of the Kondo lattice at half - filling

We examine the spin-reflection positivity of the ground state of the Kondo lattice model at half-filling with the antiferromagnetic and ferromagnetic exchange couplings J = 0. For every positive U > 0, where U is the Coulomb interaction between the conduction electrons, we can show that the ground state is unique.

ar X iv : c on d - m at / 9 70 31 05 v 1 1 1 M ar 1 99 7 Hot electron relaxation : Exact solution for a many electron model

The exact nonequilibrium time evolution of the momentum distribution for a finite many particle system in one dimension with a linear energy dispersion coupled to optical phonons is presented. For distinguishable particles the influence function of the phonon bath can be evaluated also for a finite particle density in the thermodynamic limit. In the case of fermions the exact fulfillment of the...

ar X iv : c on d - m at / 9 40 10 66 v 1 2 8 Ja n 19 94 Ground state energy and quasiparticle gaps

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 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...