  The non-perturbative functional renormalisation group (FRG) approach is
employed to study the Bose polaron problem at finite temperatures in the regime
of strong attractive bath-impurity interactions. Both two- and
three-dimensional configurations are considered. The appearance of two polaron
quasiparticle branches at finite temperatures is revealed, consistent with
recent findings by other analytical techniques. Then, ground-state polaron
energies are reported for selected interactions and temperatures within the gas
superfluid phase.
