Introduction to Quantum Noise, Measurement and Amplification

TL;DR

This paper provides a comprehensive, pedagogical overview of quantum noise, measurement, and amplification, emphasizing the quantum limits of linear amplifiers and their applications in quantum information and detection systems.

Contribution

It introduces a unified linear-response framework to analyze quantum noise and amplification, connecting quantum optics and condensed matter approaches.

Findings

Derivation of quantum noise spectra and detection methods

Analysis of the standard quantum limit for linear amplifiers

Application of the framework to electrical and mesoscopic detectors

Abstract

The topic of quantum noise has become extremely timely due to the rise of quantum information physics and the resulting interchange of ideas between the condensed matter and AMO/quantum optics communities. This review gives a pedagogical introduction to the physics of quantum noise and its connections to quantum measurement and quantum amplification. After introducing quantum noise spectra and methods for their detection, we describe the basics of weak continuous measurements. Particular attention is given to treating the standard quantum limit on linear amplifiers and position detectors using a general linear-response framework. We show how this approach relates to the standard Haus-Caves quantum limit for a bosonic amplifier known in quantum optics, and illustrate its application for the case of electrical circuits, including mesoscopic detectors and resonant cavity detectors.