Dynamics of the fractional quantum Hall edge probed by stroboscope measurements of trions

TL;DR

This paper demonstrates ultra-fast stroboscopic optical measurements of fractional quantum Hall edge dynamics, revealing the propagation of edge excitations and enabling exploration of quantum spacetime analogs in a novel experimental setup.

Contribution

It introduces a new ultra-fast optical pump-probe technique to study quantum Hall edge dynamics with picosecond resolution, distinguishing different excitation modes.

Findings

Detected quantum Hall edge propagation as a change in reflectance.

Achieved temporal resolution of approximately 1 ps.

Enabled study of quantum spacetime analogs in quantum Hall systems.

Abstract

By using observations from pump-probe stroboscopic confocal microscopy and spectroscopy, we demonstrate the dynamics of trions and the fractional quantum Hall edge on the order of $\sim1$ ps. The propagation of the quantum Hall edge state excited by a voltage pulse is detected as a temporal change in reflectance in the downstream edge probed by optical pulses synchronized with the voltage pulse. The temporal resolution of such stroboscopic pump-probe measurements is as fast as the duration time of the probe pulse ($\sim1$ ps). This ultra-fast stroboscope measurement enables us to distinguish between the normal mode of edge excitation, known as the edge magneto-plasmon or charge density wave, and other high-energy non-linear excitations. This is the only experimental method available to study the ultra-fast dynamics of quantum Hall edges, and makes it possible to derive the metric tensor $g_{\mu \nu}$ of the $(1+1)=2$-dimensional curved spacetime in quantum universe and black hole analogs implemented in the quantum Hall edge.