[vtomole]

"early days" means that the 1998 computer didn't have qubits that were below the error correction threshold. Now we have hundreds of qubits below threshold. We'll need millions of qubits like these for quantum computing to be useful. If that take decades, this is the "early days" relatively.

It's not only early days in hardware, it's early days in practical applications as well: https://arxiv.org/abs/2511.09124

[rowanG077]

I admit it's early days in practical application. But in hardware definitely not.

[vtomole]

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.

[sgt101]

can you give a bit more information on 100's of qubits below threshold? I wasn't aware of 100's...

[vtomole]

https://www.nature.com/articles/s41586-025-09848-5 performs CZ gates on up to 256 qubits with fidelities of 99.5%, which is good enough to run surface codes below threshold.