  Dense active matter, in the fluid or amorphous-solid form, has generated
intense interest as a model for the dynamics inside living cells and
multicellular systems. An extension of the random first-order transition theory
(RFOT) to include activity was developed, whereby the activity of the
individual particles was added to the free energy of the system in the form of
the potential energy of an active particle, trapped by a harmonic potential
that describes the effective confinement by the surrounding medium. This
active-RFOT model was shown to successfully account for the dependence of the
structural relaxation time in the active glass, extracted from simulations, as
a function of the activity parameters: the magnitude of the active force
($f_0$) and its persistence time ($\tau_p$). However, significant deviations
were found in the limit of large activity (large $f_0$ and/or $\tau_p$). Here
we extend the active-RFOT model to high activity using an activity-dependent
harmonic confining potential, which we solve self-consistently. The extended
model predicts qualitative changes in the high activity regime, which agree
with the results of simulations in both three-dimensional and two-dimensional
models of active glass.
