Evaluation of the Performance of a 7-Qubit Surface Code

One of the promising approaches to fault tolerant quantum computation is based on the surface code. The existence of an error rate threshold, below which increasing the code size exponentially suppresses logical errors, has been shown for many common error mechanisms [R. Raussendorf and J. Harrington, Phys. Rev. Lett. 98, 190504 (2007)]. In this talk we analyse the physical error mechanisms of a seven-qubit superconducting quantum device on which we implement the elementary operations required for a surface code. By repeated stabilizer measurements we implement a distance d=2 surface code enabling the detection of any single-qubit error. We identify the error mechanisms which have the most significant effect on the logical error rate. We further discuss how to extend our scheme to larger distance surface codes given the current performance of our device.