Permutation of two electrons within a two-dimensional array of quantum dot*

Silicon spin qubits have achieved high-fidelity one- and two-qubit gates [1,2] and promise an industrial route to fault-tolerant quantum computation. A significant next step for the development of scalable multi-qubit processors is the operation of foundry-fabricated, extendable two-dimensional (2D) quantum-dot arrays.
In this talk I will present our recent results on the control of a foundry-fabricated 2x2 array of silicon quantum dots in the few-electron regime, achieving single-electron occupation in each of the four gate-defined dots [3]. By exploiting the second dimension as well as single electron control, we induce the spatial exchange of electron pairs within the array. In principle, this discrete exchange operation is protected against charge noise, owing to Coulomb blockade, and may find use in permutational quantum computing [4].

[1] T. F. Watson et al. A programmable two-qubit quantum processor in silicon. Nature 555, 633 (2018).
[2] D. M. Zajac et al. Resonantly driven CNOT gate for electron spins. Science 359, 439 (2018).
[3] F. Ansaloni et al., arXiv:2004.00894 (2020).
[4] S. P. Jordan, Permutational Quantum Computing. Quantum Information and Computation 10, 470 (2010).