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 $10.2\le T\le 141\mathrm{mK}$. 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 $T\sim 140\mathrm{mK}$. 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.

• Received 7 June 2006

DOI:https://doi.org/10.1103/PhysRevB.74.115301