We investigate the effect of quenched bond-disorder on the anisotropic
spin-1/2 (XXZ) chain as a model for disorder induced quantum phase transitions.
We find non-universal behavior of the average correlation functions for weak
disorder, followed by a quantum phase transition into a strongly disordered
phase with only short-range xy-correlations. We find no evidence for the
universal strong-disorder fixed point predicted by the real-space
renormalization group, suggesting a qualitatively different view of the
relationship between quantum fluctuations and disorder.Comment: 4 pages, 4 postscript figures, needs RevTeX