Universal relation between the dispersion curve and the ground-state correlation length in 1D antiferromagnetic quantum spin systems

K. Okunishi, Y. Akutsu, N. Akutsu +1

We discuss an universal relation $\epsilon (i\kappa )=0$ with $\mathrm{Re}\kappa =1/\xi$ in 1D quantum spin systems with an excitation gap, where $\epsilon (k)$ is the dispersion curve of the low-energy excitatio…