The influence of repeated projective measurements on the dynamics of the
state of a quantum system is studied in dependence of the time lag Ï„
between successive measurements. In the limit of infinitely many measurements
of the occupancy of a single state the total system approaches a uniform state.
The asymptotic approach to this state is exponential in the case of finite
Hilbert space dimension. The rate characterizing this approach undergoes a
sharp transition from a monotonically increasing to an erratically varying
function of the time between subsequent measurements