  We propose a highly efficient "worm" like cluster Monte Carlo algorithm for
the quantum rotor model in the link-current representation. We explicitly prove
detailed balance for the new algorithm even in the presence of disorder. For
the pure quantum rotor model with $\mu=0$ the new algorithm yields high
precision estimates for the critical point $K_c=0.33305(5)$ and the correlation
length exponent $\nu=0.670(3)$. For the disordered case, $\mu=1/2 \pm 1/2$, we
find $\nu=1.15(10)$.
