Thermodynamics and conformal properties of XXZ chains with alternating spins

Abstract

The quantum periodic XXZ chain with alternating spins is studied. The properties of the related R-matrix and Hamiltonians are discussed. A compact expression for the ground state energy is obtained. The corresponding conformal anomaly is found via the finite-size computations and also by means of the Bethe ansatz method. In the presence of an external magnetic field, the magnetic susceptibility is derived. The results are also generalized to the case of a chain containing l different spins.

Fused integrable lattice models with quantum impurities and open boundaries

“…The model under study is related to W ZW δq and W ZW q 2 model, as already concluded in [44,42]. Indeed the central charge conjectured in [44], and found in [42] is given by impurity.…”

“…The thermodynamic Bethe ansatz equations are obtained by minimizing the free energy (δf = 0) and by virtue of (2.12), we conclude that they coincide with the ones of the model without impurities [42] and they are given by …”

Exact solution of the alternating XXZ spin chain with generic non-diagonal boundaries

“…Therefore {t (j,(s,s ′ )) } serve as the generating functionals of the conserved quantities of the associated model, whose Hamiltonian can be given by some derivative of the logarithm of the associated transfer matrix t (j,(s,s ′ )) (u) at some special points [59,71,73], and thus ensure the integrability of the model.…”

Baxter Q-operators of the XXZ chain and R-matrix factorization

“…The defining system of equations (2.4) for the operatorŘ 12 is equivalent to the following system of equations [19,27,29] R 12 · q z1∂1+z2∂2 = q z1∂1+z2∂2 ·Ř 12 (2.5)…”

“…Matching coefficients in front of q λ we derive (2.6) and (2.7) with sign plus and matching coefficients in front of q −λ we obtain the same equations (q → q −1 ) with sign minus. It is possible to show that the system of equations (2.5)-(2.7) is equivalent to the initial defining system [19,27,29].…”