Non-adiabatic holonomic quantum gates on a nitrogen-vacancy center in diamond
Silvia Arroyo Camejo (Dept. NanoBiophotonik, Max-Planck Institut für biophysikalische Chemie)

Quantum computers can tackle certain computational problems that are practically inaccessible for present classical computing architectures. Experimental imperfections and decoherence are the major obstacles on the way to the realization of a quantum computer. Quantum error correction codes only become efficacious, if the basic quantum gates reach a certain minimum fidelity. The search for realistic quantum computing architectures is, therefore, a quest for fault-tolerant hardware. To this end, quantum gates based on geometric instead of dynamic phase shifts may provide intrinsic fault-tolerance, as geometrical phases show remarkable robustness with respect to certain types of experimental errors.
Here, we demonstrate an experimental realization of an all-geometric single-qubit quantum gate on a single spin at room temperature. It is based on a recent proposal for holonomic quantum computing featuring both fast (non-adiabatic) and universal (non-Abelian) quantum gate performance. Using a singe nitrogen-vacancy color center in diamond, we achieve close to perfect quantum gate fidelities exceeding 0.98. This quantum gate realization is based on integrable and scalable hardware exhibiting a strong analogy to current silicon technology. It may thus be seen as a promising step towards viable, fault-tolerant quantum computing under ambient conditions.