We prove simplicity of all intermediate
$C^{\ast }$
-algebras
$C_{r}^{\ast }(\unicode[STIX]{x1D6E4})\subseteq {\mathcal{B}}\subseteq \unicode[STIX]{x1D6E4}\ltimes _{r}C(X)$
in the case of minimal actions of
$C^{\ast }$
-simple groups
$\unicode[STIX]{x1D6E4}$
on compact spaces
$X$
. For this, we use the notion of stationary states, recently introduced by Hartman and Kalantar [Stationary
$C^{\ast }$
-dynamical systems. Preprint, 2017, arXiv:1712.10133]. We show that the Powers’ averaging property holds for the reduced crossed product
$\unicode[STIX]{x1D6E4}\ltimes _{r}{\mathcal{A}}$
for any action
$\unicode[STIX]{x1D6E4}\curvearrowright {\mathcal{A}}$
of a
$C^{\ast }$
-simple group
$\unicode[STIX]{x1D6E4}$
on a unital
$C^{\ast }$
-algebra
${\mathcal{A}}$
, and use it to prove a one-to-one correspondence between stationary states on
${\mathcal{A}}$
and those on
$\unicode[STIX]{x1D6E4}\ltimes _{r}{\mathcal{A}}$
.