Quantum error correction

Now in previous lessons we've mentioned quantum error correction and its importance. So in this lesson we're going to take a little closer look at that entire process. So let's start with quantum fault tolerance theorem. It's also sometimes called the quantum threshold theorem. We talked about this briefly in the last lesson. we need to get the physical error rate below some particular threshold, and then we can use quantum error correction algorithms to reduce the error rate further to a level that's tolerably low. Now that might sound odd to you, a tolerable level of error? Well there's no such thing as perfect communication. Even the classical communications you use now are subject to errors, so the same will be true in quantum communication, but we need to get it down to a tolerably low level. Also remember that quantum computers, by their nature, are probabilistic, not deterministic, which means even more errors are going to occur. Also recall that noise and decoherence are major…