Controlled quantum dot array segmentation via a highly tunable interdot tunnel coupling

TL;DR

This paper demonstrates nanosecond control of inter-dot tunnel coupling in a triple quantum dot system, enabling precise array segmentation and promising advancements for scalable quantum computing.

Contribution

It introduces a highly tunable inter-dot tunnel coupling technique that allows rapid switching between coupling regimes, facilitating array control and isolation.

Findings

Achieved nanosecond control of tunnel rates.

Demonstrated isolation of a quantum dot subarray.

Enabled charge displacement and readout in a segmented array.

Abstract

Recent demonstrations using electron spins stored in quantum dots array as qubits are promising for developing a scalable quantum computing platform. 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 can lead to a simplification for tuning and offers a protection against unwanted charge displacement. In a triple quantum dot system, we demonstrate a nanosecond control of the inter-dot tunnel rate permitting to reach the two extreme regimes, large GHz tunnel coupling and sub-Hz isolation between adjacent dots. We use this novel development 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.