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Quantum spin ladder systems associated with su(2|2)

A. Foerster·K. E. Hibberd·J. R. Links·I. Roditi
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Abstract

Two integrable quantum spin ladder systems will be introduced associated with the fundamental su(2|2) solution of the Yang-Baxter equation. The first model is a generalized quantum Ising system with Ising rung interactions. In the second model the addition of extra interactions allows us to impose Heisenberg rung interactions without violating integrability. The existence of a Bethe ansatz solution for both models allows us to investigate the elementary excitations for antiferromagnetic rung couplings. We find that the first model does not show a gap whilst in the second case there is a gap for all positive values of the rung coupling.

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A. Foerster, K. E. Hibberd, J. R. Links, I. Roditi. 2000-10-02. Quantum spin ladder systems associated with su(2|2). https://arxiv.org/abs/cond-mat/0010035

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