  Tidal interactions play a crucial role in deciphering gravitational wave
signals emitted by the coalescence of binary systems. They are usually
quantified by a set of complex coefficients which include tidal Love numbers,
describing the conservative response to an external perturbation. In the static
case, these are found to vanish exactly for asymptotically flat black holes in
general relativity in four space-time dimensions, and recently they have been
generalized to dynamical interactions. In the context of response theory, the
retarded Green's function provides the complete description of the behavior of
dynamical systems. In this work we investigate the relation between Love
numbers and Green's functions, and highlight the relevance of radiation
reaction effects to their connection. As a special case, we discuss BTZ black
holes, where the absence of radiative modes allows us to make a direct link
between them.
