vtomole

Good point. I didn't sufficiently delineate what counts as a scientific problem and what counts as an engineering problem in QC.

Quantum theory, like all physical theories, makes predictions. In this case, quantum theory predicts that if the physical error rate of qubits is below a threshold, then error correction can be used to increase the quality of a logical at arbitrarily high levels. This prediction can be false. We currently don't know all of the potential noise sources that will prevent us from building a quantum logic gate that is of similar quality as a classical logic gate.

Building thousands of these logical qubits is an engineering problem similar to Dyson spheres and space elevators. You're right that the lower levels of building 1 really good logical qubit doesn't mean that we can build thousands of them.

If our case, even the lower-levels haven't been validated. This is what I meant when I implied that the project of building a large-scale QC might teach us something new about physics.

Sure, I'm not disagreeing that this processor is noisy, just providing enough context to say that it's fine. Historically, these devices improve enough to be under threshold at which point it doesn't matter that they are noisy cause error correction protocols can be run on top of them.

Quantum theory is so unlikely to be wrong that if large-scale fault tolerant quantum computers could not be built, the effort to try to build them will not be a dead end, but instead a revolution in physics.

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.

Depends on what we mean by "early days on hardware".

If we mean "we've have been working on this for almost 3 decades. That's a very long time to be working on something!". I agree.

If we mean "We just now only have a few logical qubits that outperform their physical counterparts and we'll need thousands of these logical qubits to run anything useful" then we are still in the early days.

> 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.

The graphs aren't telling you that QC hardware is not improving at a super-exponential pace?

There are no real world use cases today. The hardware is not advanced enough yet, but it's improving exponentially.

Oops, updated. Thanks!