Quantum Computation and Information Seminar 

05/05/2006, 15:00 — 16:00 — Room P4.35, Mathematics Building
Daniel Gottesman, Perimeter Institute

The Threshold for Fault-tolerance

Quantum computers are likely to be much more vulnerable to noise than classical computers, so it is likely they will need to be encoded using quantum error-correcting codes and computations will be performed using fault-tolerant protocols. One critical result states that there is a threshold error rate, such that arbitrarily long reliable computations are possible if the error rate per gate and time step in the computer are below the threshold. I will give an overview of some recent work on the threshold, with a slight emphasis on recent work by Aliferis, Preskill, and myself. We gave a new proof of the threshold which is simpler and more general than previous proofs, and proved a higher value of the threshold error rate. We also showed that a threshold exists with more general non-Markovian environments than was previously known.