Gate-based high fidelity spin readout in a CMOS device.

Area of Science:

• Quantum Computing
• Solid-State Physics
• Semiconductor Spintronics

Background:

• Large-scale quantum computing requires compact qubit unit cells with high-fidelity functionalities for error correction.
• Electron spins in silicon quantum dots offer high control fidelity and compatibility with industrial semiconductor platforms.
• An efficient and scalable spin readout scheme is a critical missing component for silicon-based quantum computing.

Purpose of the Study:

• To demonstrate a high-fidelity, robust, and scalable spin readout method for silicon quantum dots.
• To address the need for efficient spin readout in complementary metal-oxide-semiconductor (CMOS) compatible quantum devices.
• To enable single-shot spin readout with high accuracy for advancing quantum error correction.

Main Methods:

• Utilized radio-frequency gate reflectometry in a CMOS device featuring a qubit dot and an ancillary dot coupled to an electron reservoir.
• Implemented a latched spin blockade mechanism involving electron exchange between the ancillary dot and the reservoir.
• Performed single-shot spin readout measurements to assess fidelity and performance.

Main Results:

• Achieved an average spin readout fidelity exceeding 98% with a 0.5 ms integration time.
• Demonstrated a robust readout method that maintains high fidelity up to 0.5 K.
• Successfully integrated qubit and ancillary dots with an electron reservoir for scalable readout.

Conclusions:

• The developed gate reflectometry technique provides a high-fidelity, scalable single-shot spin readout for silicon quantum dots.
• This method is compatible with CMOS technology, paving the way for co-integration of quantum and classical electronics.
• The achieved fidelity and robustness are significant steps towards implementing quantum error correction protocols.