Low-temperature asymptotics of integrable systems in an external field

An asymptotic low-temperature expansion is performed for an integrable bosonic lattice model and for the critical spin-1/2 Heisenberg chain in a magnetic field. The results apply to the integrable Bose gas as well. We also comment on a high-temperature expansion of the bosonic lattice model.Comment: 17 pages, 2 figure

Exact thermodynamic limit of short-range correlation functions of the antiferromagnetic XXZXXZ-chain at finite temperatures

We evaluate numerically certain multiple integrals representing nearest and next-nearest neighbor correlation functions of the spin-1/2 $XXZ$ Heisenberg infinite chain at finite temperatures.Comment: 22 pages, 6 figure

The anisotropic multichannel spin-SS Kondo model: Calculation of scales from a novel exact solution

A novel exact solution of the multichannel spin-$S$ Kondo model is presented, based on a lattice path integral approach of the single channel spin-1/2 case. The spin exchange between the localized moment and the host is of $XXZ$-type, including the isotropic $XXX$ limit. The free energy is given by a finite set of non-linear integral equations, which allow for an accurate determination of high- and low-temperature scales.Comment: 18 pages, 7 figure