  In this somewhat pedagogical paper we revisit complementarity relations in
bipartite quantum systems. Focusing on continuous variable systems, we examine
the influential class of EPR-like states through a generalization to Gaussian
states and present some new quantitative relations between entanglement and
local interference within symmetric and asymmetric double-double-slit
scenarios. This approach is then related to ancilla-based quantum measurements,
and weak measurements in particular. Finally, we tie up the notions of
distinguishability, predictability, coherence and visibility while drawing some
specific connections between them.
