Topological quantum computing (TQC) is a newer type of quantum computing that uses "braids" of particle tracks, rather than actual particles such as ions and electrons, as the qubits to implement computations. Using braids has one important advantage: it makes TQCs practically immune to the small perturbations in the environment that cause decoherence in particle-based qubits and often lead to high error rates.
Ever since TQC was first proposed in 1997, experimentally realizing the appropriate braids has been extremely difficult. For one thing, the braids are formed not by the trajectories of ordinary particles, but by the trajectories of exotic quasiparticles (particle-like excitations) called anyons. Also, movements of the anyons must be non-Abelian, a property similar to the non-commutative property in which changing the order of the anyons' movements changes their final tracks. In most proposals of TQC so far, the non-Abelian statistics of the anyons has not been powerful enough, even in theory, for universal TQC.
Now in a new study published in Physical Review Letters, physicists Abolhassan Vaezi at Cornell University and Maissam Barkeshli at Microsoft's research lab Station Q have theoretically shown that anyons tunneling in a double-layer system can transition to an exotic non-Abelian state that contains "Fibonacci" anyons that are powerful enough for universal TQC.
"Our work suggests that some existing experimental setups are rich enough to yield a phase capable of performing 'universal' TQC, i.e., all of the required logical gates for the performance of a quantum computer can be made through the braiding of anyons only," Vaezi told Phys.org. "Since braiding is a topological operation and does not perturb the low-energy physics, the resulting quantum computer is fault-tolerant."
Via Dr. Stefan Gruenwald