  We revisit the calculation of bosonic dark matter absorption via electronic
excitations. Working in an effective field theory framework and consistently
taking into account in-medium effects, we clarify the relation between dark
matter and photon absorption. As is well-known, for vector (dark photon) and
pseudoscalar (axion-like particle) dark matter, the absorption rates can be
simply related to the target material's optical properties. However, this is
not the case for scalar dark matter, where the dominant contribution comes from
a different operator than the one contributing to photon absorption, which is
formally next-to-leading-order and does not suffer from in-medium screening. It
is therefore imperative to have reliable first-principles numerical
calculations and/or semi-analytic modeling in order to predict the detection
rate. We present updated sensitivity projections for semiconductor crystal and
superconductor targets for ongoing and proposed direct detection experiments.
