We present perturbative analytical results of the Landau level quasienergy
spectrum, autocorrelation function and out of plane pseudospin polarization for
a single graphene sheet subject to intense circularly polarized terahertz
radiation. For the quasienergy spectrum, we find a striking non trivial
level-dependent dynamically induced gap structure. This photoinduced modulation
of the energy band structure gives rise to shifts of the revival times in the
autocorrelation function and it also leads to modulation of the oscillations in
the dynamical evolution of the out of plane pseudospin polarization, which
measures the angular momentum transfer between light and graphene electrons.
For a coherent state, chosen as an initial pseudospin configuration, the
dynamics induces additional quantum revivals of the wave function that manifest
as shifts of the maxima and minima of the autocorrelation function, with
additional partial revivals and beating patterns. These additional maxima and
beating patterns stem from the effective dynamical coupling of the static
eigenstates. We discuss the possible experimental detection schemes of our
theoretical results and their relevance in new practical implementation of
radiation fields in graphene physics.Comment: 12 pages, 5 figures. Accepted version for publication in Physical
Review