This is an updated version of supplementary information to accompany "Quantum
supremacy using a programmable superconducting processor", an article published
in the October 24, 2019 issue of Nature. The main article is freely available
at this https URL Summary of changes since
arXiv:1910.11333v1 (submitted 23 Oct 2019): added URL for qFlex source code;
added Erratum section; added Figure S41 comparing statistical and total
uncertainty for log and linear XEB; new References [1,65]; miscellaneous
updates for clarity and style consistency; miscellaneous typographical and
formatting corrections.

更新版本的补充信息，是 2019 年 10 月 24 日发表在 Nature 杂志上的 “使用可编程超导处理器实现量子霸权” 的文章的附加内容，主要更新了与 qFlex 源代码的 URL、勘误部分、比较 log 和 linear XEB 的统计和总不确定度的图 S41、参考文献和风格等方面的细节。