Flux induced re-entrant dynamics in the quantum walk of interacting bosons

Abstract

We study the QW of two interacting bosons on a two-leg ladder lattice in the presence of an artificial magnetic field. By considering an uniform flux piercing through the ladder, we show that in the limit of strong onsite repulsion and dominant rung-hopping, an initially slow dynamics becomes fast, then slow and fast again with increase in the flux strength indicating a re-entrant dynamics. This unusual behaviour is found to be associated with the formation, breaking and reformation of a bound pair state along the rung of the ladder. In addition to this we also find a re-entrant behaviour in the chiral dynamics where the chirality in the system first increases and then decreases with increase in interaction. We establish this unusual re-entrant behaviour in the dynamics by analysing the radial velocity, spreading of correlation, center-of-mass shearing and energy band diagrams.