Spatiotemporal imaging of gate-controlled multipath dynamics of fractional quantum Hall edge excitations

TL;DR

This study visualizes and controls the complex multipath dynamics of fractional quantum Hall edge excitations, revealing how local confinement influences their propagation and enabling new experimental platforms.

Contribution

It provides the first spatiotemporal imaging of gate-controlled multipath edge excitations in fractional quantum Hall systems with high temporal resolution.

Findings

Switching between mesa-defined and gate-defined trajectories observed.

Propagation becomes more dispersive in a multipath landscape.

Long-range optical response extends over tens of micrometers.

Abstract

Quantum Hall edge excitations, whose low-energy behavior admits a chiral conformal-field-theory description, are a promising platform for engineered dynamical experiments, including analog-spacetime proposals. However, establishing their edge dynamics in realistic electrostatic landscapes is essential for controlled dynamical experiments and has remained experimentally challenging. Here we report spatiotemporal imaging of gate-controlled multipath dynamics of edge excitations in a $\nu = 1/3$ fractional quantum Hall device using stroboscopic time-resolved photoluminescence microscopy and spectroscopy with $\sim$100-ps resolution. By tuning a control-gate-defined potential landscape, we observe switching between mesa-defined and gate-defined trajectories and identify an intermediate regime in which a single launched excitation accesses multiple pathways. Time-resolved measurements at downstream locations reveal gate-dependent arrival times and pronounced temporal broadening, showing that the propagation dynamics are strongly modified by the local confinement and become increasingly dispersive in a multipath landscape. We further observe a long-range transverse optical response extending tens of micrometers into the bulk and persisting over distances exceeding 200 $\mu$m downstream, consistent with the near-field component of an edge magnetoplasmon. These results establish direct experimental access to controllable multipath edge dynamics in the fractional quantum Hall regime and suggest a platform for engineered nonequilibrium and interference-based experiments, as well as future analog-spacetime studies in quantum Hall edge systems.