We have implemented high-fidelity two-qubit logic gates in silicon quantum dots with 99% fidelity (Nature 526 (7573), 410-414; Nature 569, 532–536; Nat. Phys. (2024)) and achieved a single-qubit gate fidelity of 99.96% (Nature Electronics 2, 151–158 (2019)). We focus on the detailed characterization of qubits to understand their behavior under different conditions, particularly the impact of non-local and non-Markovian noise. By characterizing noise in multi-qubit systems, we aim to distinguish between classical and quantum noise effects. We seek to determine if spatially correlated noise, rather than localized noise, limits the scalability of semiconductor qubits. Additionally, understanding correlated noise allows us to use its properties to entangle multiple qubits. 

We pioneered spin qubit readout for bilayer graphene quantum dots, achieving a high signal-to-noise ratio of ~7 (PRX Quantum 3 (2), 020343), and achieved spin and valley readout using the Pauli blockade mechanism (Nature Physics 20 (3), 428-434). Additionally, fast charge readout is enabled by coupling quantum dots to high-impedance NbTiN resonators (Nano Lett 24, 7508–7514). We will investigate circuit QED for fast quantum non-demolition readout, probing noise, and achieving long-range, high-fidelity coupling between semiconductor spin qubits, which is important for a fully scalable, error-corrected quantum architecture.