We study the occupation of two electrostatically-coupled single-level quantum
dots with spinless electrons as a function of gate voltage. While the total
occupation of the double-dot system varies monotonically with gate voltage, we
predict that the competition between tunneling and Coulomb interaction can give
rise to a nonmonotonic filling of the individual quantum dots. This
non-monotonicity is a signature of the correlated nature of the many-body
wavefunction in the reduced Hilbert space of the dots. We identify two
mechanisms for this nonmonotonic behavior, which are associated with changes in
the spectral weights and the positions, respectively, of the excitation spectra
of the individual quantum dots. An experimental setup to test these predictions
is proposed.Comment: 4 pages, 5 figure