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Effective chiral-spin Hamiltonian for odd-numbered coupled Heisenberg chains

V. Subrahmanyam
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Abstract

An $L \times \infty$ system of odd number of coupled Heisenberg spin chains is studied using a degenerate perturbation theory, where $L$ is the number of coupled chains. An effective chain Hamiltonian is derived explicitly in terms of two spin half degrees of freedom of a closed chain of $L$ sites, valid in the regime the inter-chain coupling is stronger than the intra-chain coupling. The spin gap has been calculated numerically using the effective Hamiltonian for $L=3,5,7,9$ for a finite chain up to ten sites. It is suggested that the ground state of the effective Hamiltonian is correlated, by examining variational states for the effective chiral-spin chain Hamiltonian.

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V. Subrahmanyam. 1994-10-10. Effective chiral-spin Hamiltonian for odd-numbered coupled Heisenberg chains. https://doi.org/10.1103/physrevb.50.16109

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