  The approach to equilibrium is studied for long-range quantum Ising models
where the interaction strength decays like r^{-\alpha} at large distances r
with an exponent $\alpha$ not exceeding the lattice dimension. For a large
class of observables and initial states, the time evolution of expectation
values can be calculated. We prove analytically that, at a given instant of
time t and for sufficiently large system size N, the expectation value of some
observable <A>(t) will practically be unchanged from its initial value <A>(0).
This finding implies that, for large enough N, equilibration effectively occurs
on a time scale beyond the experimentally accessible one and will not be
observed in practice.
