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arXiv · hep-th/9303043

Thermodynamics of Integrable Chains with Alternating Spins

H. J. de Vega·Luca Mezincescu·Rafael I. Nepomechie
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Abstract

We consider a two-parameter $(\bar c, \tilde c)$ family of quantum integrable 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 $T << H$. In the antiferromagnetic $(\bar c > 0, \tilde c > 0)$ case, the model has two gapless excitations. In particular, for $\bar c = \tilde c$, the model is conformally invariant and has central charge $c_{vir} = 2$. When one of these parameters is zero, the Bethe Ansatz equations admit an infinite number of solutions with lowest energy.

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H. J. de Vega, Luca Mezincescu, Rafael I. Nepomechie. 1993-03-31. Thermodynamics of Integrable Chains with Alternating Spins. https://doi.org/10.1103/physrevb.49.13223

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