  The properties of mixed eigenstates in a generic quantum system with
classical counterpart that has mixed-type phase space, although important to
understand several fundamental questions that arise in both theoretical and
experimental studies, are still not clear. Here, following a recent work
[\v{C}.~Lozej {\it et al}. Phys. Rev. E {\bf 106}, 054203 (2022)], we perform
an analysis of the features of mixed eigenstates in a time-dependent
Hamiltonian system, the celebrated kicked top model. As a paradigmatic model
for studying quantum chaos, kicked top model is known to exhibit both classical
and quantum chaos. The types of eigenstates are identified by means of the
phase space overlap index, which is defined as the overlap of the Husimi
function with regular and chaotic regions in classical phase space. We show
that the mixed eigenstates appear due to various tunneling precesses between
different phase space structures, while the regular and chaotic eigenstates
are, respectively, associated with invariant tori and chaotic component in
phase space. We examine how the probability distribution of the phase space
overlap index evolves with increasing system size for different kicking
strengths. In particular, we find that the relative fraction of mixed states
exhibits a power-law decay as the system size increases, indicating that only
purely regular and chaotic eigenstates are left in the strict semiclassical
limit. We thus provide further verification of the principle of uniform
semiclassical condensation of Husimi functions and confirm the correctness of
the Berry-Robnik picture.
