We revisit with another view point the construction by R. Brylinski and B. Kostant of minimal representations of simple Lie groups. We start from a pair
$\left( V,\,Q \right)$ , where
$V$ is a complex vector space and
$Q$ a homogeneous polynomial of degree 4 on
$V$ . The manifold
$\Xi $ is an orbit of a covering of Conf
$\left( V,\,Q \right)$ , the conformal group of the pair
$\left( V,\,Q \right)$ , in a finite dimensional representation space. By a generalized Kantor-Koecher-Tits construction we obtain a complex simple Lie algebra
$\mathfrak{g}$ , and furthermore a real form
${{\mathfrak{g}}_{\mathbb{R}}}$ . The connected and simply connected Lie group
${{G}_{\mathbb{R}}}$ with
$\text{Lie}\left( {{G}_{\mathbb{R}}} \right)\,=\,{{\mathfrak{g}}_{\mathbb{R}}}$ acts unitarily on a Hilbert space of holomorphic functions defined on the manifold
$\Xi $ .