[GS_C_MS] Efficient encoded qubit schemes in semiconductor quantum dot systems
ABSTRACT
Localized spins in semiconductor quantum dots offer a promising path toward scalable quantum computing. This talk provides an overview of semiconductor qubit architectures and explores advanced encoding strategies designed to overcome current experimental hurdles. While individual electron spins offer a straightforward implementation, achieving scalable control remains a significant challenge. As an alternative, multi-spin systems enable all-electrical gate operations via exchange coupling. I will discuss how to optimize these 'exchange-only' qubits against charge noise by utilizing sweet spots in the parameter space and how to efficiently implement single-qubit gate operations with simultaneous control of the exchange couplings. These approaches were recently validated by experimental demonstrations. In the second half, I will present a new proposal for a 'minimal' singlet-singlet qubit. By encoding information in singlet states, we can decouple the qubit from magnetic noise. While this typically requires four spins, I propose a more efficient two-spin version in a triple quantum dot. This system combines the best of both worlds: robust coherence and simplified electrical control, making it a compelling candidate for large-scale architectures.
