Photoinduced correlated electron dynamics in a two-leg ladder Hubbard system

Photoinduced carrier dynamics in a correlated electron system on a coupled two-leg ladder lattice are studied. The two-leg ladder Hubbard model is analyzed utilizing the exact diagonalization method based on the Lanczos algorithm in finite-size clusters. In order to reveal the transient carrier dynamics after photoirradiation, we calculate the low-energy components of the hole kinetic energy, the pair-field correlation function, the optical conductivity spectra, and other characteristics. It is shown that the photoinduced metallic-like state appears in a half-filled Mott insulating state, while the low-energy carrier motion is suppressed by photoirradiation in the case of hole-doped metallic states. These photoinduced changes in the electron dynamics are associated with changes in the carrier-pair coherence; they are not attributed to a naive thermalization, and are associated with a ladder-lattice effect instead. Based on the numerical results, optical control of hole pairs using double-pulse pumping is demonstrated. Implications for recent optical pump-probe experiments are presented.