  We demonstrate that quantum dynamical localization in the Arnold web of
higher-dimensional Hamiltonian systems is destroyed by an intrinsic classical
drift. Thus quantum wave packets and eigenstates may explore more of the
intricate Arnold web than previously expected. Such a drift typically occurs,
as resonance channels widen toward a large chaotic region or toward a junction
with other resonance channels. If this drift is strong enough, we find that
dynamical localization is destroyed. We establish that this drift-induced
delocalization transition is universal and is described by a single transition
parameter. Numerical verification is given using a time-periodically kicked
Hamiltonian with a four-dimensional phase space.
