"Because there are no known fundamental obstacles to such scalability (practical quantum computer with large number of qubits), it has been suggested that failure to achieve it would reveal new physics" -Emanuel Knill
I feel that the most recent papers are becoming more conservative about their predictions on the feasibility of quantum computing despite fact that there is work stating that fault tolerant quantum computation is possible with two ingredients:
- Maximum Error/Gate about 10^-4 to 10^-5
- Effective error correction codes with ancillary qubits.
Is Fault-Tolerant Quantum Computation Really Possible?
which I also like for its entertaining and straightforward writing style.