  We study the large deviations of the power injected by the active force for
an Active Ornstein-Uhlenbeck Particle (AOUP), free or in a confining potential.
For the free-particle case, we compute the rate function analytically in
d-dimensions from a saddle-point expansion, and numerically in two dimensions
by a) direct sampling of the active work in numerical solutions of the AOUP
equations and b) Legendre-Fenchel transform of the scaled cumulant generating
function obtained via a cloning algorithm. The rate function presents
asymptotically linear branches on both sides and it is independent of the
system's dimensionality, apart from a multiplicative factor. For the confining
potential case, we focus on two-dimensional systems and obtain the rate
function numerically using both methods a) and b). We find a different scenario
for harmonic and anharmonic potentials: in the former case, the phenomenology
of fluctuations is analogous to that of a free particle, but the rate function
might be non-analytic; in the latter case the rate functions are analytic, but
fluctuations are realised by entirely different means, which rely strongly on
the particle-potential interaction.
