Large-scale quantum computers must be built upon quantum bits that are both highly coherent and locally controllable. We demonstrate the quantum control of the electron and the nuclear spin of a single 31P atom in silicon, using a continuous microwave magnetic field together with nanoscale electrostatic gates. The qubits are tuned into resonance with the microwave field by a local change in electric field, which induces a Stark shift of the qubit energies. This method, known as A-gate control, preserves the excellent coherence times and gate fidelities of isolated spins, and can be extended to arbitrarily many qubits without requiring multiple microwave sources.
@article{arxiv.1503.05985,
title = {Electrically controlling single spin qubits in a continuous microwave field},
author = {Arne Laucht and Juha T. Muhonen and Fahd A. Mohiyaddin and Rachpon Kalra and Juan P. Dehollain and Solomon Freer and Fay E. Hudson and Menno Veldhorst and Rajib Rahman and Gerhard Klimeck and Kohei M. Itoh and David N. Jamieson and Jeffrey C. McCallum and Andrew S. Dzurak and Andrea Morello},
journal= {arXiv preprint arXiv:1503.05985},
year = {2015}
}