Confusions about some symbols in QC

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In summary, the conversation discusses the presence of lines in the figures in Nielsen's book, specifically in relation to the X-box, the H gates, and the quantum gates in the "Nomenclature and notation" section. It is mentioned that some of the lines appear to be inconsistent and may be typographical errors due to the figures being rendered in LaTeX. It is also suggested to refer to correct examples on Wikipedia for clarification.
  • #1
Haorong Wu
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TL;DR Summary
Confusions about some symbols in QC
There are some pictures in Nielsen's book that I find confusing:

微信图片_20190523080457.jpg
Why there is a line half-crossing the X-box?

微信图片_20190523080451.jpg
Similarly, why there is a line connecting to ##f \left ( x \right )##?

微信图片_20190523080448.jpg
There are two H gates between ##\left | \psi _0 \right >## and ##\left | \psi _1 \right >##. Why one of them has a line crossing it, while the other one only has a line half-crossing it?

微信图片_20190523080443.jpg
Similarly, why the H gates have no lines crossing them in this picture? In the "Nomenclature and notation" section, the quantum gates are all crossed by lines. What's the differences between them?

Well, if there are just several inconsistent pictures, I would say the book has some errors. But I find there are pretty much strange appearances. Maybe I overlook some important part about those lines?
 
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These are just "typographical" error. The figures appear to have been done in LaTeX, so it may just be a problem of how they were rendered for the book.
 
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DrClaude said:
These are just "typographical" error. The figures appear to have been done in LaTeX, so it may just be a problem of how they were rendered for the book.

(@.@)...Ah..All right. So, should there be lines crossing those squares?
 
  • #5

1. What is QC and why is it important in science?

QC stands for Quality Control, and it is a process used in science to ensure that the data collected and the results obtained are accurate and reliable. This is important because it allows researchers to make informed decisions and draw valid conclusions from their experiments.

2. What are some common symbols used in QC and what do they represent?

Some common symbols used in QC include the mean (μ), standard deviation (σ), and standard error of the mean (SEM). The mean represents the average value of a set of data, the standard deviation measures the spread of the data around the mean, and the standard error of the mean is a measure of the precision of the mean.

3. What is the difference between precision and accuracy in QC?

Precision refers to the consistency or reproducibility of results, while accuracy refers to how close the results are to the true value. In QC, precision is important for ensuring that results can be replicated, while accuracy is important for obtaining reliable and valid data.

4. How is QC used in laboratory experiments?

In laboratory experiments, QC is used to monitor and control various aspects of the experiment, such as the equipment used, the conditions under which the experiment is conducted, and the data collected. This helps to identify and eliminate any potential sources of error and ensure the reliability of the results.

5. What are some common sources of error in QC?

Some common sources of error in QC include human error, equipment malfunction, environmental factors, and sample contamination. These errors can affect the accuracy and precision of the results, and it is important to identify and address them in order to obtain reliable data.

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