Perfect state transfer and maximal entanglement in a trimer of three-level systems

We analyze a quantum wire that consists of a linear chain of three qutrits with nearest-neighbor interactions and detuning on the central qutrit. We derive the detuning conditions for perfect state transfer of a double excitation and for maximal entanglement between the first and third qutrits. We also analytically determine the times for perfect state transfer and maximal entanglement, which are found to be periodic. We also show that perfect state transfer is a necessary condition for maximal entanglement, with the first occurrence of maximal entanglement at half the time for the first occurrence of perfect state transfer.