Dynamics of photoexcited states in strongly correlated electron systems.

We theoretically investigate the dynamics of the photoexcited state in the strongly correlated low-dimensional electron systems. In the two-dimensional case, the ultrafast relaxation originating from the transfer of photogenerated charges in the antiferromagnetic background is followed by the slower one originating from the spin structure rearrangement with the new charge distributions. This clearly shows the difference in the relaxation between charge and spin degrees of freedom. In the one-dimensional case, spin-charge separation holds and the mechanical coherence is preserved.