Griffiths-McCoy singularities in random quantum spin chains: Exact results
Ferenc Iglói, István A. Kovács
We consider random quantum (tight-binding, XX, and Ising) spin chains in the off-critical region and study their Griffiths-McCoy singularities. These are obtained from the density of states of the low-energy excitations, which is exactly calculated by the Dyson-Schmidt method. In large finite systems, the low-energy excitations are shown to follow the statistics of extremes and their distribution is given by the Fr\'echet form. The relation between the Dyson-Schmidt technique and the strong disorder renormalization group method is also discussed.
arXiv:0803.2617•Physical Review B•Apr 8, 2008•4 citations