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arXiv · 0904.0001

Lattice vs. continuum theory of the periodic Heisenberg chain

Michael Bortz·Michael Karbach·Imke Schneider·Sebastian Eggert
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Abstract

We consider the detailed structure of low energy excitations in the periodic spin-1/2 XXZ Heisenberg chain. By performing a perturbative calculation of the non-linear corrections to the Gaussian model, we determine the exact coefficients of asymptotic expansions in inverse powers of the system length N for a large number of low-lying excited energy levels. This allows us to calculate eigenenergies of the lattice model up to order order N^-4, without having to solve the Bethe Ansatz equations. At the same time, it is possible to express the exact eigenstates of the lattice model in terms of bosonic modes.

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Michael Bortz, Michael Karbach, Imke Schneider, Sebastian Eggert. 2009-03-31. Lattice vs. continuum theory of the periodic Heisenberg chain. https://doi.org/10.1103/physrevb.79.245414

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