Quantum metrology in the noisy intermediate-scale quantum era

TL;DR

This paper reviews quantum metrology's potential for ultra-precise measurements, discusses the impact of noise, and explores strategies to overcome decoherence to realize quantum advantages in realistic conditions.

Contribution

It provides a comprehensive overview of quantum metrology principles, resources, and the challenges posed by noise, including the no-go theorem and active control methods.

Findings

Quantum resources like entanglement and squeezing can enhance measurement sensitivity.

Decoherence degrades quantum resources, limiting measurement precision.

Active control strategies can mitigate noise effects in quantum metrology.

Abstract

Quantum metrology pursues the physical realization of higher-precision measurements to physical quantities than the classically achievable limit by exploiting quantum features, such as entanglement and squeezing, as resources. It has potential applications in developing next-generation frequency standards, magnetometers, radar, and navigation. However, the ubiquitous decoherence in the quantum world degrades the quantum resources and forces the precision back to or even worse than the classical limit, which is called the no-go theorem of noisy quantum metrology and greatly hinders its applications. Therefore, how to realize the promised performance of quantum metrology in realistic noisy situations attracts much attention in recent years. We will review the principle, categories, and applications of quantum metrology. Special attention will be paid to different quantum resources that can bring quantum superiority in enhancing sensitivity. Then, we will introduce the no-go theorem of noisy quantum metrology and its active control under different kinds of noise-induced decoherence situations.