[bob1029]

> Is that a crazy conspiracy idea, or actually a possibility?

I am investing in IBM under the assumption that this is an actual possibility. Their public QC roadmap actually looks like a realistic journey now.

I strongly believe that the NSA, et. al. currently have access to a very powerful quantum computer - likely constructed by IBM under contract.

The game theory around this is such that it is impossible for me to accept that there are zero secret quantum computers in existence by now. There is too much to lose by not playing that game as hard as you can.

[eigenket]

Speaking as a researcher in quantum computing (albiet completely on the theory side, with no practical knowledge of experiments). It seems that actually making a quantum computer which is useful (i.e. has error rate below the threshold you need for error correction to work) is incredibly difficult. I wouldn't be surprised if various secret agencies (specifically in the USA and China) have tried, but I would be quite surprised if they had succeded.

(I deleted my previous edit because I had misread part of what you wrote.)

[abdullahkhalids]

You are probably mistaken. The number of people with the right expertise to build QCs is very limited - only a few hundred people with world class PhDs in quantum computing are produced every year across the world. A small fraction are truly innovative - the ones who can act as leaders to build something real.

The challenge of building QCs - as evidenced by billions of dollars worth of research in them - is many orders of magnitude more difficult than say the Manhattan project. The latter put together the best of the best on the project. You are suggesting a scenario where a tiny fraction of the best of the best are secreted away, with many of their past collaborators unaware of their doings, and have successfully built a QC.

While the many brilliant best of the best who are working publicly, with many billions of dollars of research funding are currently only making very slow progress. It simply does not square.

[contact9879]

Reminds me of how everyone who knew anything about the physics academia scene in the 30s/40s knew what was going on at Los Alamos. Second-order effects are extremely hard to obscure.

[paradox460]

The secrecy around Los Alamos was less what they were doing and more how they were getting it done and how far along they were