Four single-spin Rabi oscillations in a quadruple quantum dot

Scaling up qubits is a necessary step to realize useful systems of quantum computation. Here, we demonstrate coherent manipulations of four individual electron spins using a micro-magnet method in each dot of a quadruple quantum dot—the largest number of dots used for the single spin control in multiple quantum dots. We observe Rabi oscillations for each dot through electron spin resonance, evaluate the spin-electric coupling of the four dots, and finally discuss practical approaches to independently address single spins in multiple quantum dot systems containing even more quantum dots.