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。

可编程超导处理器量子霸权” 的补充信息

Supplementary information for "Quantum supremacy using a programmable  superconducting processor"

The main promise of quantum computing is to efficiently solve certain
problems that are prohibitively expensive for a classical computer. Most
problems with a proven quantum advantage involve the repeated use of a black
box, or oracle, whose structure encodes the solution. One measure of the
algorithmic performance is the query complexity, i.e., the scaling of the
number of oracle calls needed to find the solution with a given probability.
Few-qubit demonstrations of quantum algorithms, such as Deutsch-Jozsa and
Grover, have been implemented across diverse physical systems such as nuclear
magnetic resonance, trapped ions, optical systems, and superconducting
circuits. However, at the small scale, these problems can already be solved
classically with a few oracle queries, and the attainable quantum advantage is
modest. Here we solve an oracle-based problem, known as learning parity with
noise, using a five-qubit superconducting processor. Running classical and
quantum algorithms on the same oracle, we observe a large gap in query count in
favor of quantum processing. We find that this gap grows by orders of magnitude
as a function of the error rates and the problem size. This result demonstrates
that, while complex fault-tolerant architectures will be required for universal
quantum computing, a quantum advantage already emerges in existing noisy
systems

使用超导体五比特处理器，对基于 oracle 的问题进行求解，经过实验验证，在现有的嘈杂系统中，量子计算机的查询次数明显比经典计算机少，这种差距会随着误差率和问题大小的增加而不断扩大，这证明了量子优势确实在现有的嘈杂系统中出现了。