Quantum fluctuation of light limits the sensitivity of advanced laser interferometric gravitational-wave detectors. It is one of the principal obstacles on the way towards the next-generation gravitational-wave observatories. The envisioned significant improvement of the detector sensitivity requires using quantum non-demolition measurement and back-action evasion techniques, which allow us to circumvent the sensitivity limit imposed by the Heisenberg uncertainty principle. In our previous review article (Danilishin and Khalili in Living Rev Relativ 15:5, 2012), we laid down the basic principles of quantum measurement theory and provided the framework for analysing the quantum noise of interferometers. The scope of this paper is to review novel techniques for quantum noise suppression proposed in the recent years and put them in the same framework. Our delineation of interferometry schemes and topologies is intended as an aid in the process of selecting the design for the next-generation gravitational-wave observatories.

光的量子涨落限制了先进激光干涉引力波探测器的灵敏度。这是通往下一代引力波天文台的主要障碍之一。探测器灵敏度的预期显着提高需要使用量子非破坏测量和反作用规避技术，这使我们能够规避海森堡不确定性原理所施加的灵敏度限制。在我们之前的综述文章（Danilishin 和 Khalili in Living Rev Relativ 15:5, 2012）中，我们阐述了量子测量理论的基本原理，并提供了分析干涉仪量子噪声的框架。本文的范围是回顾近年来提出的量子噪声抑制新技术，并将它们置于同一框架中。我们对干涉测量方案和拓扑的描述旨在为下一代引力波天文台选择设计的过程提供帮助。