  Quantum adiabaticity is characterized by the evolution of a quantum system
that remains close to an instantaneous eigenstate of a time-varying
Hamiltonian, precluding transitions between eigenstates. Employing Floquet
formalism, we rigorously establish two sufficient conditions that ensure
quantum adiabaticity in periodically driven systems, applicable for time
evolution of arbitrary length. Distinct from traditional conditions, the
Floquet-based conditions are tight for certain specific parameter regimes,
dispense with supplementary constraints, and suggest the possibility of
adiabaticity at high frequencies. We provide three illustrative examples that
compare and contrast the Floquet conditions with traditional ones.
