2.1 The boson problem 10 2.1. 1 The с= 0 case 10 2.1. 2 The с= oo case 11 2.1. 3 Scattering
states of Bose particles with finite interaction 12 2.1. 4 Periodic boundary conditions 14 2.1 …

In this contribution we review the theory of integrability of quantum systems in one spatial
dimension. We introduce the basic concepts such as the Yang-Baxter equation, commuting …

The free energy and correlation lengths of the spin-1/2 XYZ chain are studied at finite
temperature. We use the quantum transfer matrix approach and derive non-linear integral …

The Yang-Baxter algebras (YBA) are introduced in a general framework stressing their
power to exactly solve the lattice models associated to them. The algebraic Bethe Ansatz is …

An approach is presented for calculating the free energy as well as the correlation lengths of
integrable quantum chains at arbitrary finite temperatures. The method is applied to critical …

Two-dimensional fermionic field theories are defined on a diagonal lattice obtained by
discretizing Minkowski space-time in light-cone coordinates. This approach leads to local …

We present numerical and analytical results for the thermodynamical properties of the spin-
1/2 Heisenberg chain at arbitrary external magnetic field. Special emphasis is placed on …

抄録 Presented is a new approach to the study of one dimensional quantum spin systems at
finite temperature. The approach is based upon a general structure of solvable models; the …

The procedure for obtaining integrable vertex models via reflection matrices on the square
lattice with open boundaries is reviewed and explicitly carried out for a number of two-and …

A set of equations that allows one to calculate the correlation length and the free energy of
the S= 1/2 XYZ chain at a given temperature is obtained. It contains infinite unknown …