Protocol for Purifying Noisy Preparation and Measurements of Qubits

TL;DR

This paper introduces a protocol to purify noisy state preparation and measurement processes in quantum computing, significantly reducing errors and improving the reliability of quantum information tasks.

Contribution

The authors present a novel protocol for purifying noisy SPAM in qubits, achieving error suppression down to 10^{-6} with multiple ancillas, applicable to superconducting qubits.

Findings

Error rates can be suppressed from 0.05 to 10^{-3} with one ancilla.

Error suppression down to 10^{-6} is possible with four ancillas.

The protocol is feasible with superconducting qubits.

Abstract

Noise affecting qubit preparation and measurements accounts for a significant fraction of errors in quantum information processing. This is especially critical in tasks like variational quantum algorithms, quantum error correction, and entanglement distribution through repeaters. In this work, we present a protocol to purify noisy SPAM, effectively suppressing these errors to an arbitrarily low level. For instance, in a realistic scenario where qubits contain error rates around $0.05$ in both preparation and measurement, the protocol can suppress error rates up to $10^{-3}$ with a single ancilla and $10^{-6}$ with four ancillas. We show how to distill error-free SPAM by repeating noisy SPAMs. The protocol is also feasible with superconducting qubits. We envisage that our results can be used to realize quantum information tasks in computing and communication with negligible SPAM errors.