Qubit operations and statistics in a two dimensional 10-qubit array

Planar germanium qubits in Ge/SiGe heterostructures are a rising platform for quantum computation [1]. Their favourable properties have enabled the demonstration of a four-qubit quantum processor [2] and high-fidelity two-qubit gates [3]. In this talk, we discuss the operation of a two-dimensional array with both dense and sparse hole fillings. In the dense regime, the array hosts 10 Loss and DiVincenzo qubits with single gate fidelities above 99%. We assess the driving efficiency and the g-factor variability of all 10 qubits as a function of the 22 gates in the array. By extracting valuable statistics, we evaluate driving locality, directionality, and crosstalk in a dense qubit array. We repeat these experiments with single-hole, three-hole, and five-hole occupations per dot to identify the optimal operating regime in a dense spin qubit array. By configuring the array with sparse hole filling, we reduce the number of qubits but gain the ability to shuttle spins. This approach opens new avenues for operating and characterising the array and enables the possibility of performing hopping single-qubit gates [4].

References :

[1] G. Scappucci et al., Nature Reviews Materials 6, 926-943(2021)

[2] N.W. Hendrickx et al., Nature 591, 580–585 (2021)

[3] C.A. Wang et al., Science 385, 447 (2024)

[4] F. Borsoi et al., Nature Nano. 19, 21-27 (2024)