There are already Computer Science and Theoretical Computer Science sites that should cover Quantum Computing topics. There's no reason to needlessly multiply stack exchange sites.

Proposal: Quantum Computing

  • I wrote an answer explaining why Quantum Computing as a whole is not on topic on either CS or TCS SEs, before getting a comment that suggested the issue isn't specifically about subsuming it into CS and TCS, but subsuming it into multiple SEs. Either way, would you be able to clarify what it is you're asking? Thanks Oct 6, 2017 at 10:01

4 Answers 4


Looking on the Stack Overflow blog, Merging Season (it may be a number of years old, but it's linked on the Area 51 FAQ, so is still relevant)

So: the right size might be somewhere around the size of a university department

As time would have it, there is now at least one centre with a similar number of members to a small department (and other institutes with over 100 members). These will only increase in size as time goes on. This puts the area of Quantum Computing 'somewhere around the size of a university department', making it potentially 'the right size', although a better indicator of 'right size' would perhaps be given by having a large number of followers, which this proposal does have (currently the third highest of the proposals in the definition stage). This puts it in the place of being big enough to be a valid area for SE.

Now, the next point in the blog is the one being addressed in this question:

Here’s the best we could come up with for deciding whether site X should be subsumed by site Y:

  1. Almost all X questions are on-topic for site Y

While there are quantum computing tags on the sites you mentioned, there are also quantum computing tags on other sites (There are also a few quantum computing questions on Worldbuilding, but I feel they're substantially different enough to be not on topic here):

  • Theoretical Computer Science: 296 questions
  • Computer Science: 150 questions
  • Stack Overflow: 73 questions
  • Physics: 440 questions
  • Math Overflow: 30 questions
  • Mathematics: 112 questions
  • Information Security: 10 questions (+5 on post-quantum [cryptography])

Or, to put it another way, while Computer Science and Theoretical Computer Science SEs "cover Quantum Computing topics", they don't cover all Quantum Computing topics. This can also be demonstrated by looking at the list in the What questions should be on topic for Quantum Computing? question, where there are example questions about the definition as well as from both the computer science and physics sides. Similarly, looking at the list of questions asked so far in this proposal, there are questions related to computer science, physics, maths, security and engineering.

The above is extremely strong evidence that Quantum Computing cannot just covered by one or two SE sites, but would require at least 7 or potentially 8 (including a feasible tag on engineering). This shows that the first rule is not valid. That is, Most Quantum Computing questions are not on topic for any other single SE site and so, Quantum Computing should not be subsumed by one.

Furthermore, as shown above, Quantum Computing/technologies/engineering is now starting to branch into being another subject and so no longer deserves to be split into smaller areas that are individually part of different subjects (maths, computer science, physics, engineering, security) but is now a valid area by itself and so, should be considered as a whole. Considering it as a whole area by itself then means that, as there is no single site that covers all of this, the best option is to have another SE site for Quantum Computing.

Edit: Question areas on Quantum Computing not on Topic on any other SE site:

One of the comments on this answer said that I needed to make the argument "all of Stack Exchange together does not sufficiently cover QC". I do disagree with this, as whether or not an area should be considered for an SE is based more on whether it is big before looking at potential issues such as 'can it be subsumed in Y' (i.e. The area as a whole should be looked at before deciding whether or not it should be subsumed into Y, never mind X, Y and Z). In addition, the question is about specifically subsuming it into Computer Science and Theoretical Computer Science which clearly would not work, although votes and said comment suggest that this isn't actually the problem, which instead appears to be subsuming it into many different parts of SE. Anyway, some questions areas that are not on topic on any SE site (that I'm aware of) include:

  • Quantum chip design
  • Quantum chip engineering (although it's not impossible that this could be accepted in either engineering or electrical engineering)
  • Difficulties of simulating a specific system on a quantum chip (as quantum chips are far from ideal yet)
  • Possibly analogue simulations using quantum chips (may be on topic for physics)
  • benchmarking
  • testing
  • real-life implementations of a quantum network (and the potential issues)
  • using e.g. IBM's quantum experience
  • possibly using commercially available hardware (e.g. Quantum Random Number Generators)
  • The argument you need to make is not that no single site covers all of QC, but that all of Stack Exchange together does not sufficiently cover QC and therefore a new space is necessary. As your own response shows, this is not true - it seems quite the opposite.
    – Nij
    Oct 6, 2017 at 4:16
  • So can I assume that you say the same thing of Ask Ubuntu, Server fault, Electrical Engineering, Mathematica, software engineering, DevOps, Computational Science, Sports, bioinformatics and language learning? The above linked blog post explains about the different levels of the scale of the SE sites and QC is a big enough area that it is an appropriate size for an SE site. Then you look at subsuming it into other sites - keeping up to date on QC on SE means following all of them, which isn't exactly convenient Oct 6, 2017 at 8:48
  • Also, @Nij - if you're going down that route, can I request that the question title be edited, as QC as a whole is clearly not on topic on TCS or CS SEs and the question you're now asking/problem you're having with this proposal is slightly different to what that title and question are suggesting? Oct 6, 2017 at 8:55
  • You want edits on the question, ask the writer. Yes, there are areas that should have been subsumed by existing sites, but for one reason or another, were allowed to stand apart. Some you even mentioned, though others have a clear border from any related site here. But whatever has lead to the current state for them, you have not shown would also apply for QC.
    – Nij
    Oct 6, 2017 at 9:41
  • 2
    @Nij Not being an active user on any of those sites, I'm not really able to answer what lead them to the state they are in. I have, however, edited my answer to include question topics that aren't on topic on any current SE that I know of Oct 6, 2017 at 9:49
  • tbh, this answer nails it. Also, there seems to be many people, experts and not, interested in participating in this site. I.e., there's a critical mass.
    – auden
    Oct 11, 2017 at 0:46

Quantum computing is a broad and expansive topic, but it is also specialized. Therefore, the fact of the matter is that the overwhelming majority of people checking these other sites don’t know much about it, though I’d venture a guess that people in physics are more likely to know about quantum information. If quantum information questions are to gain a good deal of visibility among people who have the ability to answer, a focused site is needed. It would be most helpful to researchers in the field to have a place where we know that many experts are frequently checking it and contributing content. You won’t get nearly that same effect of frequently checking and contributing content on any other site. I’ve done work in quantum computing for about 3.5 years and I only go on Stackexchange sites when I have a specific question about a specific topic, whether it be math, physics, or computer science. I don’t frequently check any of these because I’ve been focused on quantum information and related topics. If however there was a high-quality Q&A site devoted to quantum information and if I knew that it attracted experts and others who are knowledgeable and somewhat deeply involved in the field, I might check it just because, that is just to see what is going on even when I don’t have a specific question. I expect others who are seriously involved in the subject to be more likely to do the same under those circumstances (given a dedicated site). That ensures a substantially greater proportion of high quality content, and actually a higher volume of content on the topic. Frankly, I’d be in favor of it being more broadly on quantum information and not just quantum computing: so I’d favor it including quantum communication, quantum cryptography, etc.


I disagree. If you take the current situation, questions related to quantum cryptography is not welcomed in crypto exchange nor computer science exchange. We need a stack exchange for Quantum Computing.

Nathan Aw


Quantum Computing did not exist with all other disciplines. It is quite new, and it will keep growing up. As everyone knows in general that the distance between transistors inside chips is decreasing and will only result in a quantum property trouble, we will need an entirely different computing; the Quantum Computing. I think the proposal for a new site for this is appropriate and very timely.

  • This doesn't address any of the criticism or issues with the separate proposal at all. 90% of its text explaining what quantum computing is, in a highly misleading or outright wrong way, and irrelevant to why the sites that already covered the subject would not be sufficient.
    – Nij
    Dec 26, 2017 at 22:09

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