Pipes, Loops and Snakes: Quantum computing leverage shuttling in semiconductor devices [note this talk is for the session on high-fidelity shuttling of semiconductor spin qubits]

Semiconductor devices present unique opportunities for fault tolerant, large scale quantum computing. The prospect of fast and high fidelity shuttling is particularly exciting. I’ll focus on two shuttling-based paradigms and I’ll use the surface code as the example protocol, although the methods are not limited to this. In the looped pipeline approach multiple qubits move in closed cycles -- remarkably, this allows an effective 3D architecture although the physical device is 2D. This can be very helpful in routing information, and for supporting otherwise-impossible codes. A more radical paradigm is “snakes on a plane” which reformats logical qubits into 1D entities that can then move freely over a 2D lattice. This creates a vulnerability that can be tackled using a powerful resource called decoder confidence (a.k.a. decoder soft information). All these ideas are compatible both with single-electron physical qubits and with singlet/triplet encoding, the latter bringing the advantage of ‘erasure conversion’.