  We propose a method to probe states in the Mott insulator regime produced
from a condensate in an optical lattice. We consider a system in which we
create time-dependent number fluctuations in a given site by turning off the
atomic interactions and lowering the potential barriers on a nearly pure Mott
state to allow the atoms to tunnel between sites. We calculate the expected
interference pattern and number fluctuations from such a system and show that
one can potentially observe a deviation from a pure Mott state. We also discuss
a method in which to detect these number fluctuations using time-of-flight
imaging.
