  In ultracold atomic gases, a unique interplay arises between phenomena known
from condensed matter physics, few-body physics and chemistry. Similar to an
electron in a solid, an impurity in an ultracold gas can get dressed by
excitations from the medium, forming a quasiparticle called the polaron. We
study how dressing of an impurity leads to a modification of its chemical
reactivity. Using a Gaussian state variational method in the frame of the
impurity, we demonstrate that three-body correlations lead to an instability of
the polaron. This instability is connected to an Efimov resonance, but shifted
to smaller interactions by many-body effects, showing that polaron formation
stimulates Efimov physics and the associated chemistry.
