  We investigate the impact of quenched disorder on the dynamical correlation
functions of two-leg quantum spin ladders. Perturbative continuous unitary
transformations with the help of white graphs and bond-operator mean-field
theory are used to calculate the one- and two-triplon contribution of the
zero-temperature dynamical structure factor. Disorder results in huge effects
on quasi-particles as well as composite bound states due to localization. This
leads to intriguing quantum structures in dynamical correlation functions well
observable in spectroscopic experiments.
