Perfect coherent shift of bound pairs in strongly correlated systems

TL;DR

This paper demonstrates that perfect coherent shift of bound pairs can be achieved in extended Bose-Hubbard and Fermi-Hubbard models, with conditions depending on interaction strengths and initial states.

Contribution

It extends the concept of coherent shift to new models and identifies conditions for perfect shift of different bound pairs.

Findings

Perfect coherent shift is achievable in extended Hubbard models.

Conditions depend on interaction strength and initial state for Bose on-site bound pairs.

Other bound pairs exhibit state-independent perfect shift.

Abstract

In the present work we extend the concept of coherent shift for the extended Bose-Hubbard model and Fermi-Hubbard model. We present two types of local bound pair (BP) for Bose system and one type for Fermi system. It is shown exactly that the perfect coherent shift can be achieved in such models. We find that for a Bose on-site BP, the perfect coherent shift condition depends on the nearest-neighbor interaction strength and the momentum of the incident single particle wavepacket, while for the other two types of BPs, it is independent of the initial state in the proposed systems.