Defect induced nonequilibrium quantum dynamics in an interacting Bose–Hubbard flux ladder

Abstract

The interacting Bose-Hubbard flux ladder provides an ideal model to probe novel quantum phenomena of many-body systems. Here, we report on the first direct observation of dynamical quantum phase transition (DQPT) in interacting Bose-Hubbard flux ladder induced by defect perturbation, which provides a new scheme for experimental design and manipulation of the DQPT in ultracold atomic system. Under the mean-field approximation, DQPT is identified by resolving the order parameter and the temporal evolution of patterns of atomic density distributions and local current configurations of the system. The threshold for occurrence of DQPT is obtained analytical and the physical mechanism of DQPT is revealed explicitly. Periodic appearance and annihilation of dynamical vortex and the manifestation of symmetry restoration after perturbation from broken-symmetry phase are observed. A thorough connection among the order parameter dynamics, the underlying ground state phase transition and nonequilibrium dynamics is established in real time and real space for the first time. Interestingly, by quenching the defect, the underlying ground state phases are captured, which provides a feasible dynamical measurement scheme for the observation of the underlying ground state phase which is challenging to reach experimentally.

Magnetic-induced chiral dynamics in an extended two-leg bosonic ladder

“…Considering the left-right leg degree of freedom of the ladder system as an effective spin, the magnetic field locks spin and momentum of the particle, resulting in an effective spin-orbit interaction and leading to well-defined edge modes with chirality [35,36]: the atoms in the two legs move in opposite direction. Under an external perturbation, the magnetic ladder system exhibits rich chiral dynamics, such as chiral Bloch oscillation (BOs), superfluidity, coherent transformation, Landau-Zener tunneling [37][38][39][40][41], Landau-Zener-Stuckelberg-Majorana interferometry [42,43], nonequilibrium quantum dynamics [44], etc. Among them, the BOs, observed in many physical systems, including semiconductor superlattices [45] and ultracold atoms [46][47][48][49][50][51], are of great significance for study of band structures and their topological properties of the system.…”

The ground state, localization, and chiral edge dynamics of a three-legged bosonic magnetic ladder

“…Based on the dynamic research of the magnetic ladder system, it is shown that there are also abundant nonlinear dynamic characteristics in this system, e.g. chiral Bloch-Zener dynamics, Stückelberg interference, critical slowing down of the collective modes, dynamics supersolidlike phases, and nonequilibrium quantum dynamics [36][37][38][39][40].…”