[vtomole]

> Is there a guarantee that these things can and will work given enough time?

Quantum theory predicts that they will work given enough time. If they don't work, there is something about physics that we are missing.

[zarzavat]

Quantum theory says that quantum computers are mathematically plausible. It doesn't say anything about whether it's possible to construct a quantum computer in the real world of a given configuration. It's entirely possible that there's a physical limit that makes useful quantum computers impossible to construct.

[vtomole]

Quantum theory says that quantum computers are physically plausible. Quantum theory lies in the realm of physics, not mathematics. As a physical theory, it makes predictions about what is plausible in the real world. One of those predictions is that it's possible to build a large-scale fault tolerant quantum computer.

The way to test out this theory is to try out an experiment to see if this is so. If this experiment fails, we'll have to figure out why theory predicted it but the experiment didn't deliver.

[pohl]

Sounds like a pursuit where we win either way

[stocksinsmocks]

Publishing findings that amount to an admission that you and others spent a fortune studying a dead end is career suicide and guarantees your excommunication from the realm of study and polite society. If a popular theory is wrong, some unlucky martyr must first introduce incontrovertible proof and then humanity must wait for the entire generation of practitioners whose careers are built on it to die.

[ziofill]

Unless the overall cost is too high, but yes it's definitely worth pursuing as far as we currently know.