Experimental fault-tolerant universal quantum gates with solid-state spins under ambient conditions

Area of Science:

• Quantum Information Science
• Solid-State Physics
• Quantum Computing Hardware

Background:

• Quantum computation promises significant speedups but requires precise control of quantum systems, especially spin-qubits in solids.
• Achieving high-fidelity quantum gates under ambient conditions, crucial for fault-tolerant quantum computation, remains a major challenge due to noise.
• Nitrogen-vacancy (NV) centers in diamond are promising solid-state qubits, but their control fidelity is often limited by environmental noise.

Purpose of the Study:

• To quantitatively characterize noise sources affecting quantum gate operations in NV-center qubits.
• To develop and demonstrate strategies for suppressing noise and improving control fidelity.
• To realize a universal set of high-fidelity quantum gates at room temperature in diamond.

Main Methods:

• Utilized composite pulse techniques to mitigate the effects of environmental noise during gate operations.
• Employed an optimized control method tailored for NV-center spin qubits.
• Performed gate operations on nitrogen-vacancy centers in naturally abundant (13)C diamond at room temperature.

Main Results:

• Achieved an average single-qubit gate fidelity of 0.999952.
• Demonstrated a two-qubit gate fidelity of 0.992.
• Successfully implemented a universal set of logic gates with unprecedented fidelity under ambient conditions.

Conclusions:

• The developed strategies effectively suppress noise, enabling high-fidelity quantum gate operations in solid-state spin qubits.
• Room-temperature operation with high fidelity is achievable in NV-center systems, paving the way for practical quantum computing hardware.
• This work represents a significant step towards fault-tolerant quantum computation using scalable solid-state platforms.