  How well can we constrain the initial quantum state of metric perturbations
sourced during inflation? We exhibit an interesting new class of quantum states
that entangle the scalar metric perturbations {\zeta} with other fields such as
scalars as well as the tensor metric perturbations hij. These states are
theoretically consistent, for inflation that lasts close to its minimum number
of e-folds. They give distinguishable signatures in the power spectrum and may
be able to explain some long-standing anomalies in the CMB power spectrum. We
advocate using a generalized effective theory of quantum states (of which our
work is an example) that, using inflation as a powerful microscope, could
provide deep insights into the quantum state of matter on the smallest scales.
