Martin Nurizzo

The ability to initialize, manipulate and readout individual quantum objects in large and highly connected arrays is a prerequisite for developing a scalable quantum computing platform. Recent demonstrations using electron spins stored in quantum dots as qubits are promising for such an implementation. An ongoing effort is therefore aiming at the precise control of the quantum dots parameters in larger and larger arrays which represents a complex challenge. Partitioning of the system with the help of the inter-dot tunnel barriers could induce a simplification for tuning and a protection for unwanted charge displacement. In a triple quantum dot system, we demonstrate  a controllable inter-dot tunnel rate over 12 orders of magnitude permitting to reach the two extreme regimes, large GHz tunnel coupling and sub-Hz isolation between adjacent dots. We use this level of control to isolate a sub part of the array while performing charge displacement and readout in the rest of the system. The degree of control over the tunnel coupling achieved in a unit cell should motivate future protocol development for tuning, manipulation and readout including this capability.