  Coherent scattering of light by a single quantum emitter is a fundamental
process at the heart of many proposed quantum technologies. Unlike atomic
systems, solid-state emitters couple to their host lattice by phonons. Using a
quantum dot in an optical nanocavity, we resolve these interactions in both
time and frequency domains, going beyond the atomic picture to develop a
comprehensive model of light scattering from solid-state emitters. We find that
even in the presence of a cavity, phonon coupling leads to a sideband that is
completely insensitive to excitation conditions, and to a non-monotonic
relationship between laser detuning and coherent fraction, both major
deviations from atom-like behaviour.
