Quantum CNOT Gate for Spins in Silicon

TL;DR

This paper demonstrates a high-fidelity, resonantly-driven CNOT gate for electron spins in silicon, achieving fast operation and entanglement generation, advancing silicon-based quantum computing.

Contribution

It introduces an efficient CNOT gate for silicon electron spins using resonant driving and exchange control, overcoming previous challenges related to nuclear spin dephasing.

Findings

Single-qubit fidelities >99%

CNOT operation in ~200 ns

Bell state fidelity of 75%

Abstract

Single qubit rotations and two-qubit CNOT operations are crucial ingredients for universal quantum computing. While high fidelity single qubit operations have been achieved using the electron spin degree of freedom, realizing a robust CNOT gate has been a major challenge due to rapid nuclear spin dephasing and charge noise. We demonstrate an efficient resonantly-driven CNOT gate for electron spins in silicon. Our platform achieves single-qubit rotations with fidelities >99%, as verified by randomized benchmarking. Gate control of the exchange coupling allows a quantum CNOT gate to be implemented with resonant driving in ~200 ns. We use the CNOT gate to generate a Bell state with 75% fidelity, limited by quantum state readout. Our quantum dot device architecture opens the door to multi-qubit algorithms in silicon.