LIGO operates with quantum noise below the Standard Quantum Limit

Authors

W. Jia
V. Xu
K. Kuns
M. Nakano
L. Barsotti
M. Evans
N. Mavalvala
R. Abbott
Francisco Llamas, The University of Texas Rio Grande Valley
Volker Quetschke, The University of Texas Rio Grande ValleyFollow

Document Type

Article

Publication Date

2024

Abstract

Precision measurements of space and time, like those made by the detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO), are often confronted with fundamental limitations imposed by quantum mechanics. The Heisenberg uncertainty principle dictates that the position and momentum of an object cannot both be precisely measured, giving rise to an apparent limitation called the Standard Quantum Limit (SQL). Reducing quantum noise below the SQL in gravitational-wave detectors, where photons are used to continuously measure the positions of freely falling mirrors, has been an active area of research for decades. Here we show how the LIGO A+ upgrade reduced the detectors' quantum noise below the SQL by up to 3 dB while achieving a broadband sensitivity improvement, more than two decades after this possibility was first presented.

Recommended Citation

Jia, Wenxuan, Victoria Xu, Kevin Kuns, Masayuki Nakano, Lisa Barsotti, Matthew Evans, Nergis Mavalvala et al. "LIGO operates with quantum noise below the Standard Quantum Limit." arXiv preprint arXiv:2404.14569 (2024).