Enhanced local addressability of a spin array with local exchange pulses and global microwave driving

Abstract

Spin qubits have been an excellent candidate for scaled up quantum processors since a few decades not only due to the vastnanoelectronic device fabrication industry at their disposal but also the ability to address single spins by frequency-selective control using electron spin resonance (ESR). All the qubits having a distinguishable frequency is a prerequisite to this strategy which imposes an upper bound on the number of qubits that can be differentiated without crosstalk coming into play. There have been techniques in the literature to address individual spins for small scale devices. Here we theoretically propose a strategy to address an individual spin in a large array of spin qubits with a random distribution of g-factors by employing a combination of single-qubit and SWAP gates facilitated by a global microwave field and local exchange pulses. Consequently, only the target qubit undergoes the desired operation and all other qubits return to their original states, even qubits that share the same Larmor frequency as the target. Gate fidelities above 99% can thus be maintained for arrays containing tens of qubits.