Electrically controlling single spin qubits in a continuous microwave field

TL;DR

This paper demonstrates a method for controlling single electron and nuclear spin qubits in silicon using a continuous microwave field and local electric fields, enabling scalable quantum control without multiple microwave sources.

Contribution

It introduces A-gate control for single spins in silicon, maintaining coherence and fidelity while allowing scalable, local qubit tuning with a single microwave source.

Findings

Successful control of electron and nuclear spins in silicon.

Preservation of coherence times and gate fidelities.

Scalable qubit control with a single microwave source.

Abstract

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.