Coherent control of individual electron spins in a two-dimensional array of tunnel coupled quantum dots*

Controlling nanocircuits at the single electron spin level in quantum dot arrays is at the heart of any scalable spin-based quantum information platform. The cumulated efforts to finely control individual electron spins in linear arrays of tunnel coupled quantum dots have permitted the recent coherent control of multi-electron spins and the realization of quantum simulators. However, the two-dimensional scaling of such control is a crucial requirement for simulating complex quantum matter and for efficient quantum information processing, and remains up to now a challenge.
Here we demonstrate such two-dimensional coherent control using individual electron spins in arrays up to 9 tunnel-coupled lateral quantum dots. Two-electron spin initialization, spin readout and spin transfer enable exploration of the spin dynamics in the QDs array. We demonstrate a procedure that permits local enhancement of the tunnel coupling between two dots of the array up to a range where coherent exchange oscillations, the basis of the two-qubit gates for electron spin qubits, are observed. Taking advantage of the tunability of the structure, we finally realize complex and multi-directional displacements of one and two electrons through quantum dot arrays. This work demonstrates key quantum functionalities, crucial for using two-dimensional quantum dot arrays for quantum simulation and computation.

[1] H. Flentje, P.-A. Mortemousque, R. Thalineau, A. Ludwig, A. D. Wieck, C. Bäuerle, T.
Meunier, Coherent long-distance displacement of individual electron spins, Nat. Comm.
8, 501 (2017).
[2] P.-A. Mortemousque, H. Flentje, E. Chanrion, A. Ludwig, A. D. Wieck, M. Urdampilleta,
C. Bäuerle, T. Meunier, Coherent control of individual electron spins in a
two-dimensional array of quantum dots, Arxiv : 1809.04584