IQC Colloquium featuring Simon Benjamin, Quantum Motion

Pipes, Loops, Snakes and more: Quantum computing with semiconductor devices 

Simon Benjamin, Oxford University and Quantum Motion Ltd. 

Semiconductor devices present unique opportunities for fault tolerant, large scale quantum computing. The prospect of fast and high fidelity shuttling of electrons is particularly exciting, allowing some powerful and surprising designs. 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 approach1 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 codes2. A more radical paradigm is “snakes on a plane”3 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) that has multiple applications4. All these ideas are compatible both with single-electron physical qubits and with dual-spin encoding, the latter bringing the advantage of ‘erasure conversion’5.  

1. “Looped Pipelines Enabling Effective 3D Qubit Lattices in a Strictly 2D Device”, Zhenyu Cai, Adam Siegel and SCB, PRXQ 4, 020345, 2023 

2. “Folded Surface Code” Zhu Sun and Zhenyu Cai, arXiv:2601.19823 

3. “Snakes on a Plane: mobile, low dimensional logical qubits on a 2D surface”, Adam Siegel, et al, arxiv:2501.02120 & PRXQ 7, 010339 2026. 

4. For general intro see e.g. “Decoder confidence” arXiv:2512.15689   

5. “Erasure conversion” arXiv:2601.10461   

IQC faculty host: Jonathan Baugh

Location

QNC 0101

Add event to calendar