Explain the unequal visibility of fractional quantum Hall plateaus

Explain why the transmission signatures of different integer and fractional quantum Hall plateaus have substantially different contrasts in edge-magnetoplasmon resonators, and determine how the quantum point contact state and cavity geometry control the visibility of those signatures.

Background

The radiofrequency measurements reveal some quantum Hall plateaus more clearly than others. In particular, the ν = 4/3 signal is prominent in some configurations, whereas other fractional states are weak or absent, and the visibility appears to depend on whether a QPC is included within the EMP cavity.

The authors identify this dependence on the QPC state and geometry but do not establish its physical mechanism, making the optimization of the device for detecting fractional-state and anyonic signatures an unresolved problem.

References

The reason why some plateaus appear clearer than others is not currently understood but seems to be linked to the state and geometry of the QPC as these signatures are better seen in a "small cavity" configuration in which no QPC is included within the EMP cavity.

— Electrostatic splitting of an Edge Magnetoplasmon Resonator  (2609.05188 - Kouamé et al., 4 Sep 2026) in Section 3.3, “Signature of fractional quantum Hall plateaus in rf”