Performing Fault-Tolerant non-Clifford Gates via Coding

A fault-tolerant non-Clifford gate for the surface code in two dimensions


+  Fault-tolerant logic gates will consume a large proportion of the resources of a two-dimensional quantum computing architecture. Here we show how to perform a fault-tolerant non-Clifford gate with the surface code; a quantum error-correcting code now under intensive development. This alleviates the need for distillation or higher-dimensional components to complete a universal gate set. The operation uses both local transversal gates and code deformations over a time that scales with the size of the qubit array. An important component of the gate is a just-in-time decoder. These decoding algorithms allow us to draw upon the advantages of three-dimensional models using only a two-dimensional array of live qubits. Our gate is completed using parity checks of weight no greater than four. We therefore expect it to be amenable with near-future technology. As the gate circumvents the need for magic-state distillation, it may reduce the resource overhead of surface-code quantum computation considerably. 

Read More…

+  This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.

Source:  Science Advances  22 May 2020: Vol. 6, no. 21, eaay4929 DOI: 10.1126/sciadv.aay4929; Science Advances.  Benjamin J. Brown,  A fault-tolerant non-Clifford gate for the surface code in two dimensions…

Content may have been edited for style and clarity.