The excitation spectrum of the frustrated spin- Heisenberg chain is reexamined using variational and exact diagonalization calculations. We show that the overlap matrix of the short-range resonating valence bond states basis can be inverted which yields tractable equations for single and two spinons excitations. Older results are recovered and new ones, such as the bond-state dispersion relation and its size with momentum at the Majumdar-Ghosh point are found. In particular, this approach yields a gap opening at and an onset of incommensurability in the dispersion relation at [as in S. Brehmer \emph{et al.}, J. Phys.: Condens. Matter , 1103 (1998)]. These analytical results provide a good support for the understanding of exact diagonalization spectra, assuming an independent spinons picture.

生成讲解博客的中文版本

生成AI智能校验的中文版本