Chiral Bloch oscillation and nontrivial topology in a ladder lattice with magnetic flux

Abstract

Bloch oscillations in a tilted ladder lattice are studied in the presence of artificial magnetic flux. The oscillations exhibit chiral characteristics which may be used to distinguish the Meissner phase and the vortex phase. By incorporating the diagonal hopping into the ladder, the dynamical evolution reveals a phase transition as the diagonal hopping rate exceeds a critical value. The pseudospin polarization rotates a full circle in a Bloch oscillating period, which implies nontrivial topology of the system. At the critical point, the lowest band gap is closed and the wave packet propagates alternatively in the two bands that leads to a doubled Bloch period. Edge states arise in the region of nontrivial band topology even in the absence of chiral symmetry. Our study may provide a dynamical way to identify the quantum phases and topological transitions in condensed-matter physics.