Viktor Dukhovni wrote:
No. That's not the case. The scepticism around in principle scalability of QCs is in fact centered on whether environmental noise can be corrected in principle or not. Much has been written about this by Gil Kalai, who has a long-running debata with Scott Aaronson on this issue. Neither side has conceded.
The point of Gil should be that: https://www.quantamagazine.org/gil-kalais-argument-against-quantum-computers-20180207/ All physical systems are noisy, he argues, and qubits kept in highly sensitive “superpositions” will inevitably be corrupted by any interaction with the outside world. should, obviously, be valid. However, he overlooked a fact that "interaction with the outside world" is very strong in quantum computers running quantum algorithms where qubits directly involved in some QEC circuits are actively entangled with many other qubits outside of the QEC circuits but, still, in the quantum computers.
Time will tell who's right.
Now is the time. > The devil is in very difficult details of > the noise models that the experts don't agree on. Not. It's just straight forward. In my draft, I strictly follow the noise model by Shor that noises result in local interaction between qubits and their local environment. However, though Shor overlooked a fact that local environment states and resulting error/noise operators are different term by term if quantum state is entangled represented by superposition of many unentangled terms, the local environment states and resulting error/noise operators are different term by term. In other words, Shor thought entangled states were just as fragile/noisy as unentangled states, against a well known fact that really entangled states are a lot more fragile/noisy than unentangled states. Masataka Ohta
