Seeing topological edge and bulk currents in time-of-flight images

Abstract

Here we provide a general methodology to directly measure the topological currents emerging in the optical lattice implementation of the Haldane model. Alongside the edge currents supported by gapless edge states, transverse currents can emerge in the bulk of the system whenever the local potential is varied in space, even if it does not cause a phase transition. In optical lattice implementations the overall harmonic potential that traps the atoms provides the boundaries of the topological phase that supports the edge currents, as well as providing the potential gradient across the topological phase that gives rise to the bulk current. Both the edge and bulk currents are resilient to several experimental parameters such as trapping potential, temperature and disorder. We propose to investigate the properties of these currents directly from time-of-flight images with both short-time and long-time expansions.

arXiv comment5 pages, 5 figures

References in corpus (25)

• Topological Insulators
• Topological insulators and superconductors
• Quantum Spin Hall Effect in Graphene
• $Z_2$ Topological Order and the Quantum Spin Hall Effect
• Experimental realisation of the topological Haldane model
• Quantum Spin Hall Effect
• Creating, moving and merging Dirac points with a Fermi gas in a tunable honeycomb lattice
• Topological Quantum Matter with Ultracold Gases in Optical Lattices
• Manipulation of Majorana fermion, Andreev reflection and Josephson current on topological insulators
• Experimental reconstruction of the Berry curvature in a topological Bloch band
• Conduction of Ultracold Fermions Through a Mesoscopic Channel
• Seeing topological order in time-of-flight measurements
• Antichiral edge states in a modified Haldane nanoribbon
• Measuring quantized circular dichroism in ultracold topological matter
• Localized magnetic moments with tunable spin exchange in a gas of ultracold fermions
• Tuning the conductance of Dirac fermions on the surface of a topological insulator
• Creating State-Dependent Lattices for Ultracold Fermions by Magnetic Gradient Modulation
• Topological Valley Currents in Gapped Dirac Materials
• Effects of Smooth Boundaries on Topological Edge Modes in Optical Lattices
• Tunneling Planar Hall Effect in Topological Insulators: Spin-Valves and Amplifiers
• Topological edge states and quantum Hall effect in the Haldane model
• Currents in the Compressible and Incompressible Regions of the 2DEG
• Creating topological interfaces and detecting chiral edge modes in a 2D optical lattice
• Asymmetric population of momentum distribution by quasi-periodically driving a triangular optical lattice
• Topological bulk states and their currents

Cited by in corpus (2)

• Topological bulk states and their currents
• Phase Transition of Topological Index driven by Dephasing