Fault-tolerant quantum metrology

TL;DR

This paper introduces fault-tolerant quantum metrology, establishing noise thresholds and demonstrating improved resilience against noise using quantum error detection and Reed-Muller codes, enabling more accurate parameter estimation under noisy conditions.

Contribution

It presents the concept of fault-tolerance in quantum metrology, introduces noise thresholds, and applies quantum Reed-Muller codes with error detection to enhance noise resilience.

Findings

Improved noise thresholds over non-fault-tolerant schemes.

Use of quantum Reed-Muller codes for better phase information retrieval.

Error detection alone can achieve higher noise thresholds.

Abstract

We introduce the notion of fault-tolerant quantum metrology to overcome noise beyond our control -- associated with sensing the parameter, by reducing the noise in operations under our control -- associated with preparing and measuring probes and ancillae. To that end, we introduce noise thresholds to quantify the noise resilience of parameter estimation schemes. We demonstrate improved noise thresholds over the non-fault-tolerant schemes. We use quantum Reed-Muller codes to retrieve more information about a single phase parameter being estimated in the presence of full-rank Pauli noise. Using only error detection, as opposed to error correction, allows us to retrieve higher thresholds. We show that better devices, which can be engineered, can enable us to counter larger noise in the field beyond our control. Further improvements in fault-tolerant quantum metrology could be achieved by optimising in tandem parameter-specific estimation schemes and transversal quantum error correcting codes.