Tunable charge qubit based on barrier-controlled triple quantum dots

TL;DR

This paper proposes a tunable charge qubit in triple quantum dots, where qubit manipulation is achieved by adjusting barrier heights, enabling control over rotation axis and speed with all-electrical methods.

Contribution

It introduces a novel all-electrical control scheme for charge qubits using barrier height adjustments in triple quantum dots, enhancing tunability for quantum computing.

Findings

Rotation axis can be varied by changing barrier heights.

Rotation speed is tunable by simultaneously adjusting barriers.

All-electrical control simplifies qubit manipulation.

Abstract

We present a theoretical proposal of a tunable charge qubit, hosted in triple quantum dots. The manipulation is solely performed by changing the heights of the two potential barriers between the three dots, while the energy of all three dots are fixed. We have found that when the relative height of the two barriers are changed, the direction of the axis of rotation in performing single-qubit gates can be varied. On the other hand, the corresponding rotation speed can be tuned by raising or lowering the two barriers at the same time. Our proposal therefore allows for tunability of both the rotation axis and rotating speed for a charge qubit via all-electrical control, which may facilitate realization of quantum algorithms in these devices.