Quantum Fisher information and the localization properties of two interacting particles in one-dimensional systems

The concept of quantum Fisher information (QFI) is used to characterize the localization properties of two interacting particles with on-site interaction on a one-dimensional lattice. It is found that the localization transition can be distinctively illustrated by the evolution of QFI if no inter-particle interaction is considered. For the two-particle system in a quasi-periodic potential chain, the interaction strength dependence of the QFI can be qualitatively different in the extended states and localized ones. For the two-particle system in a slowly varying potential lattice, the QFI decreases first and then increases with the interaction strength at all the states. In addition, the interaction induced localization effect can be revealed from the QFI spectra at different interactions in the two systems investigated here. The present work demonstrates that the QFI can well characterize the localization properties for the one dimensional two-particle systems with on-site interaction.