If they are physically realizable at all in practice, then they very likely will be by 2140. But I think there's a non-negligible chance that the theory of qua

If they are physically realizable at all in practice, then they very likely will be by 2140. But I think there's a non-negligible chance that the theory of quantum mechanics will break down as we move to superpositions of 2^1024 classical states that must be faithfully represented with physical elements.