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Updated: Jun 12, 2025

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators
Published on: May 30, 2014
Squeezing the quantum noise of a gravitational-wave detector below the standard quantum limit
Wenxuan Jia1, Victoria Xu1, Kevin Kuns1
1Laser Interferometer Gravitational-Wave Observatory (LIGO) Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Abstract:
The Heisenberg uncertainty principle dictates that the position and momentum of an object cannot be simultaneously measured with arbitrary precision, giving rise to an apparent limitation known as the standard quantum limit (SQL). Gravitational-wave detectors use photons to continuously measure the positions of freely falling mirrors and so are affected by the SQL. We investigated the performance of the Laser Interferometer Gravitational-Wave Observatory (LIGO) after the experimental realization of frequency-dependent squeezing designed to surpass the SQL. For the LIGO Livingston detector, we found that the upgrade reduces quantum noise below the SQL by a maximum of three decibels between 35 and 75 hertz while achieving a broadband sensitivity improvement, increasing the overall detector sensitivity during astrophysical observations.
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