We consider a two-parameter (c̄,c) family of quantum integrable isotropic Hamiltonians for a chain of alternating spins of spin s=1/2 and s=1. We determine the thermodynamics for low-temperature T and small external magnetic field H, with TH. In the antiferromagnetic (c̄>0,c>0) case, the model has two gapless excitations. In particular, for c̄=c, the model is conformally invariant and has central charge cvir=2. When one of these parameters is zero, the Bethe ansatz equations admit an infinite number of solutions with lowest energy.
ASJC Scopus subject areas
- Condensed Matter Physics