Towards early fault tolerance on a 2 x N array of Qubits equipped with shuttling

In the paper 'Towards early fault tolerance on a 2 X N array of Qubits equipped with shuttling' (published in PRX Quantum) the authors* explain that a two-dimensional grid of locally interacting qubits is a promising platform for achieving fault-tolerant quantum computing.  Looking ahead, developing lower-dimensional structures could be beneficial.

The authors demonstrate that the constraints of two-dimensional architectures can also support fault tolerance; they explored a 2 x N array of qubits where the interactions between non-neighbouring qubits were enabled by shuttling the logical information along the rows of the array, and show that error correction is possible.  They also identified the classes of codes that are naturally suited to this platform.  

By focusing on silicon spin qubits (as a practical example for their requirements) they provide a protocol for achieving full universal quantum computation with the surface code, while also addressing the additional constraints that are specific to a silicon spin-qubit device.  They also evaluated the performance using numeral simulations for a realistic noise model which demonstrates that both the surface code and more complex quantum low-density parity-check codes efficiently suppressed the gate and shuttling noise to a level that allowed for the execution of quantum algorithms within the classically intractable regime.

This is a step closer to the execution of quantum algorithms that outperform classical machines.

* Led by this department, in collaboration with Quantum Motion and University College London.