Transport in the Laughlin quasiparticle interferometer: Evidence for topological protection in an anyonic qubit

TL;DR

This study demonstrates topological protection in a Laughlin quasiparticle interferometer, showing robust anyonic superperiodic conductance oscillations up to 140 mK, supporting potential for fault-tolerant quantum computing with anyons.

Contribution

The paper provides experimental evidence of topological protection in an anyonic qubit using a Laughlin quasiparticle interferometer, highlighting the persistence of superperiodic oscillations at relatively high temperatures.

Findings

Superperiodic conductance oscillations persist up to 140 mK.

Oscillation amplitude matches quantum-coherent thermal dephasing predictions.

Distinct temperature dependence from single-particle tunneling devices.

Abstract

We report experiments on temperature and Hall voltage bias dependence of the superperiodic conductance oscillations in the novel Laughlin quasiparticle interferometer, where quasiparticles of the 1/3 fractional quantum Hall fluid execute a closed path around an island of the 2/5 fluid. The amplitude of the oscillations fits well the quantum-coherent thermal dephasing dependence predicted for a two point-contact chiral edge channel interferometer in the full experimental temperature range 10.2<T<141 mK. The temperature dependence observed in the interferometer is clearly distinct from the behavior in single-particle resonant tunneling and Coulomb blockade devices. The 5h/e flux superperiod, originating in the anyonic statistical interaction of Laughlin quasiparticles, persists to a relatively high T~140 mK. This temperature is only an order of magnitude less than the 2/5 quantum Hall gap. Such protection of quantum logic by the topological order of fractional quantum Hall fluids is expected to facilitate fault-tolerant quantum computation with anyons.