Fault-Tolerant Postselected Quantum Computation: Schemes

TL;DR

This paper proposes methods for fault-tolerant postselected quantum computation using error-detecting codes, aiming to improve error tolerance and accuracy in quantum computations despite noisy gates.

Contribution

It introduces novel schemes for implementing fault-tolerant postselected quantum computation with noisy gates based on error-detecting codes.

Findings

Methods enable arbitrarily accurate encoded computation when no errors are detected.

Approach can prepare arbitrary stabilizer states in large error-correcting codes.

Potential to enhance error tolerance in non-postselected quantum computation.

Abstract

Postselected quantum computation is distinguished from regular quantum computation by accepting the output only if measurement outcomes satisfy predetermined conditions. The output must be accepted with nonzero probability. Methods for implementing postselected quantum computation with noisy gates are proposed. These methods are based on error-detecting codes. Conditionally on detecting no errors, it is expected that the encoded computation can be made to be arbitrarily accurate. Although the probability of success of the encoded computation decreases dramatically with accuracy, it is possible to apply the proposed methods to the problem of preparing arbitrary stabilizer states in large error-correcting codes with local residual errors. Together with teleported error-correction, this may improve the error tolerance of non-postselected quantum computation.