Semiconductor Spin Qubits

In the technological race towards a fault-tolerant quantum computer, semiconductor spin qubits have emerged as a rising star. Backed by the massive semiconductor fabrication industry that has developed for nearly half a century, and unlike other qubit platforms that struggle with compatibility with current Si/Ge processes, they have become one of the most promising platforms for realizing a quantum computer. Quantum dots, fabricated using standard semiconductor lithography techniques, theoretically possess excellent scalability. This means that the existing CMOS industrial infrastructure can be leveraged to manufacture chips containing a vast number of qubits, offering an unparalleled path and immense potential for realizing million-qubit semiconductor quantum processors.

On the other hand, due to the mobility of electrons, semiconductor spin qubits are one of the few solid-state qubit types that can be physically moved ("shuttled"), offering the potential to achieve nearly fully-connected quantum computing platforms. However, semiconductor spin qubits currently face the challenge of relatively short coherence times (compared to their gate times), partly due to the interaction of the quantum dot's electron spin with the nuclear spins in the host material. Furthermore, due to their later stage of development compared to superconducting qubits, the performance of readout and high-fidelity two-qubit gates still lags behind, making these areas major topics of current research.

This series will provide an in-depth introduction to semiconductor spin qubits!

Originally written in Chinese by the author, these articles are translated into English to invite cross-language resonance.