Quantum error correction pdf code#
Quantum error correction pdf crack#

Quantum error correction pdf code#

This code protects against a bit flip, which is the only possible error that can occur in classical computing. By measuring the states of these ancillary qubits, you learn if the three information-containing qubits are in identical states without disturbing the state of any of them. The first of these compares the first and second physical qubits the other compares the second and third. ShorвЂ™s code replaces the scales with two extra вЂњancillaвЂќ qubits. If the scales are imbalanced both times, the ball that stayed still is the culprit. If it was balanced only once, then one of the replaced balls is the odd one out. If the scale was balanced both times, then all balls are identical. The answer is to first pick two balls and compare their weights, then replace one of the balls with the remaining ball and check again. What measurements will let you determine whether there is an oddball in the mix, and if so, which one it is? YouвЂ™re given three balls that look identical, but one of the balls might have a different weight. The task is not unlike solving a simple logic puzzle. If one of the qubits was different, it would indicate that an error had occurred. Instead, he found a way to tell if the three physical qubits were in the same state as one another. Since measuring a quantum state would destroy the superposition, there wasnвЂ™t a straightforward way to check to see whether an error had occurred. The essential power of quantum computation comes from the fact that qubits can exist in a вЂњsuperpositionвЂќ of being in a combination of 0 and 1 at the same time. ShorвЂ™s quantum repeater code couldnвЂ™t be exactly the same as the classical version, though.

He used three individual вЂњphysicalвЂќ qubits to encode a single qubit of information - the вЂњlogicalвЂќ qubit. If one of the bits is different from the others, the computer can correct the error and continue the calculation. Shor modeled his protocol after the classical repeater code, which involves making copies of each bit of information, then periodically checking those copies against each other.

Quantum error correction pdf crack#

So how did Shor crack the conundrums he faced? He used the added complexity of quantum mechanics to his advantage. But at the beginning of October, researchers led by Chris Monroe, a physicist at the University of Maryland, reported that they had demonstrated many of the ingredients necessary to run an error-corrected circuit like ShorвЂ™s. вЂњWe wonвЂ™t be able to scale up quantum computers to the degree that they can solve really hard problems without it,вЂќ said John Preskill, a physicist at the California Institute of Technology.ДЄs with quantum computing in general, itвЂ™s one thing to develop an error-correcting code, and quite another to implement it in a working machine. Most physicists see it as the only path to building a commandingly powerful quantum computer.