We investigate the effect of local stochastic control errors in the
time-dependent Hamiltonian on isolated quantum dynamics. The control errors are
formulated as time-dependent stochastic noise in the Schr\"odinger equation.
For any local stochastic control errors, we establish a threshold theorem that
provides a sufficient condition to obtain the target state, which should be
determined in noiseless isolated quantum dynamics, as a relation between the
number of measurements required and noise strength. The theorem guarantees that
if the sum of the noise strengths is less than the inverse of computational
time, the target state can be obtained through a constant-order number of
measurements. If the opposite is true, the required number of measurements
increases exponentially with computational time. Our threshold theorem can be
applied to any isolated quantum dynamics such as quantum annealing, adiabatic
quantum computation, the quantum approximate optimization algorithm, and the
quantum circuit model.Comment: 4 pages, 0 figur