  Wave-particle duality and the superposition of quantum mechanical states
furnish quantum mechanics with unique features which distinguishes it from
classical mechanics and give it the apparently counter-intuition
interpretation. The two principles are responsible for the observation of the
interference effects of quantum particles such as electrons, atoms and
molecules. Visibility is a measure of the wave nature and can be though of as a
"normalized" coherence quantifier. Reduction in the visibility arises from
dephasing (decoherence): a process in which the relative phases get partially
or totally destroyed leading to domination of the particle nature. We calculate
the coherence and visibility of an ensemble of a single electron and two
electrons on two sites using the density matrix formulation. For such a system
of electrons, visibility and predictability (a particle nature measure) follow
an oscillatory-complementary temporal evolution and neither of them depends on
the single particle energy.
