Contagious error sources would need time travel to prevent quantum computation

Abstract

We consider an error model for quantum computing that consists of "contagious quantum germs" that can infect every output qubit when at least one input qubit is infected. Once a germ actively causes error, it continues to cause error indefinitely for every qubit it infects, with arbitrary quantum entanglement and correlation. Although this error model looks much worse than quasi-independent error, we show that it reduces to quasi-independent error with the technique of quantum teleportation. The construction, which was previously described by Knill, is that every quantum circuit can be converted to a mixed circuit with bounded quantum depth. We also consider the restriction of bounded quantum depth from the point of view of quantum complexity classes.

7 pages. Minor revision, discussion, and two references added in response to informal comments

References in corpus (2)

• Topological fault-tolerance in cluster state quantum computation
• Classical simulation of commuting quantum computations implies collapse of the polynomial hierarchy

Cited by in corpus (2)

• The Quantum Computer Puzzle (Expanded Version)
• Propagation of correlations in Local Random Quantum Circuits