| > If current quantum computers were scaled up to more qubits That depends on what you mean by "scaled up". There is a concept of "Quantum Volume" that exists, which basically means the depth of the longest qubit circuit you can pull off. https://en.wikipedia.org/wiki/Quantum_volume 'Simply' (it's never simple ;) ) adding qubits to a machine does not necessarily increase its Quantum Volume. Decreasing the noise typically will. However, there is a threshold at which point you can scale up mostly indefinitely. This is what the whole Quantum Error Correction is all about. https://en.wikipedia.org/wiki/Quantum_error_correction There is a paper https://arxiv.org/abs/1905.09749 That goes into a clear discussion of how to build a quantum computer and the associated thresholds that would allow you to do so. There is a minimum number of qubits needed (that work perfectly), but the paper analyzes how many qubits you'd need under realistic assumptions about how many noisy qubits you'd need to get error correcting qubits at the needed reliability. |