  Doublon-holon dynamics is investigated in a pumped one-dimensional Hubbard
model with a staggered on?site Coulomb interaction at half-filling. When the
system parameters are set to be in the Mott insulating regime the equilibrium
sublattice density of states exhibits several characteristic peaks,
corresponding to the lower and upper Hubbard bands as well as hybridization
bands. We study the linear absorption spectrum and find two main peaks
characterizing the photon frequencies which excite the ground state to an
excited state. For a system driven by a laser pulse with general intensity and
frequency, both the energy absorption and the doublon-holon dynamics exhibit
distinct behaviors as a function of laser amplitude and frequency.
Single-photon processes are observed at low laser intensity where the energy is
absorbed for resonance laser frequencies. For strong laser intensity
multi-photon induced dynamics are observed in the system, which are confirmed
by an evaluation of the Loschmidt amplitude. The contribution of multi-photon
processes to site-specific double occupancy is also characterized by the
generalized Loschmidt amplitude. The site-selective doublon-holon dynamics are
observed in both the one and multi-photon processes and the site-selective
behavior is explained within a quasiparticle picture. Our study suggests
strategies to optically engineer the doublon-holon dynamics in one dimensional
strongly correlated many-body systems.
