Interacting bosonic flux ladders with a synthetic dimension: Ground-state phases and quantum quench dynamics

Abstract

Flux ladders constitute the minimal setup enabling a systematic understanding of the rich physics of interacting particles subjected simultaneously to strong magnetic fields and a lattice potential. In this work, the ground-state phase diagram of a flux-ladder model is mapped out using extensive density-matrix renormalization-group simulations. The emphasis is put on parameters which can be experimentally realized exploiting the internal states of potassium atoms as a synthetic dimension. The focus is on accessible observables such as the chiral current and the leg-population imbalance. Considering a particle filling of one boson per rung, we report the existence of a Mott-insulating Meissner phase as well as biased-ladder phases on top of superfluids and Mott insulators. Furthermore, we demonstrate that quantum quenches from suitably chosen initial states can be used to probe the equilibrium properties in the transient dynamics. Concretely, we consider the instantaneous turning on of hopping matrix elements along the rungs or legs in the synthetic flux-ladder model, with different initial particle distributions. We show that clear signatures of the biased-ladder phase can be observed in the transient dynamics. Moreover, the behavior of the chiral current in the transient dynamics is discussed. The results presented in this work provide guidelines for future implementations of flux ladders in experimental setups exploiting a synthetic dimension.

Topological Lifshitz transitions, orbital currents, and interactions in low-dimensional Fermi gases in synthetic gauge fields

“…Finally, in connection with recent [9,10] and future experiments, finite temperature effects should be also considered. The extension of the mean-field theory developed here to finite temperatures is rather straightforward, but unbiased calculations of the orbital current or susceptibility at finite temperature using DMRG may be more demanding (although they have been already undertaken for the closely related system of interacting hard-core bosons in flux ladders [40]). Qualitatively, we expect that the quantum phase transitions of the Lifshitz type studied here will become crossovers, and finite temperature effects will round the sharpness of cusps in the orbital current and the singularities of the susceptibility.…”

Snapshot-based detection of $\frac{1}{2}$-Laughlin states: coupled chains and central charge

“…Varying φ from 0 to 2π, we obtain the many-body Chern number as the winding number As a limiting case we simulated two-leg ladders (L y = 2) subject to a perpendicular magnetic field. Similar models were studied with various modifications in earlier studies [57][58][59][60][61][62][63][64][65] We find that the physics in this regime is qualitatively different from the extended systems with L y ≥ 3 studied in the main text. The extrapolated central charge for the ladder system is depicted in Fig.…”

Heat, particle, and chiral currents in a boundary driven bosonic ladder in the presence of a gauge field

“…One interesting aspect to explore further is the inclusion of repulsive on-site interaction in the bosonic ladder with gauge field. Such systems can exhibit many more interesting energy band structures and phases, such as vortex-superfluid, Meissner-superfluid, vortex-Mott insulator, and Meissner-Mott insulator, depending on the density of the bosons [51][52][53][54]. It would be thus interesting to explore how the inclusion of on-site interactions can change the thermopower of the ladder.…”