| Not the parent (and gotten my PhD more then 25 years ago), but the answer is no. Quantum mechanics is a fickly thing. Schrödingers cat has not been observed ;-) because scaling kills the quantum mechanical properties. My (entirely theoretical) PhD project dealt with a 2 dimensional electromagnetic cavity, with one 'perfect' mirror (100% reflecting) and one 'imperfect', say 99.999999999% reflecting. My results were that if you started with a 'squeezed' vacuum, in just a few roundtrips, the 'squeeziness' disappears, due to the bath/loss of the non-perfect mirror. My 'gut feeling' tells me that if we have enough qbits to actually factor something more then 2x2, the loss/bath effect will delete any useful use of the quantum computer. So I am in the 'will not happen' category. (Not in 1, not in 5, not in 30 years, not in 500 years). This is different from classical error correction: as far as I understand Schors algorithm, there is no 'get N approximate answers, combine them, and get a better answer' part in there. While classically you could do 100 measurements and get a better approximation then with just one. |
You are also somewhat wrong about the combining N approximate answers and combining them. It is correct that that the "repetition code" approach (repeat the same calculation a bunch of time and average the results) does not work for quantum computers. However there are quantum error correcting codes which do appear to work, although they require sufficiently small initial error rates (so-called thresholds) in order to help.