  We study zero temperature fluctuations of charge flow in a metallic loop
induced by time dependent magnetic flux, and solve for the optimal way of
varying flux in order to minimize noise. Optimal time dependence of the flux is
a sum of ``solitons,'' each corresponding to quantized flux change. Minimal
noise coincides with that for the binomial distribution with the number of
attempts equal to the number of solitons and with the probabilies defined by
the scattering matrix of the system.
