Einstein–Podolsky–Rosen squeezing experiment for future gravitational-wave detectors

Next-generation Earth-based gravitational-wave (GW) detectors, such as the Einstein Telescope and Cosmic Explorer, will be at least an order of magnitude larger and more sensitive than current ones. Their quantum noise reduction systems, using linear filter cavities, will also scale up. To reduce system size and complexity, the EPR conditional squeezing scheme has been proposed as a cost-effective alternative to km-long filter cavities, while also aiming at lower optical losses. This experiment is designed to validate EPR conditional squeezing in a suspended small-scale interferometer limited by quantum radiation pressure noise, in the frequency band relevant to large-scale GW observatories, ranging from a few tens of Hz to a few kHz. It incorporates advanced methods such as reflective mode-matching telescopes and an automated data acquisition system.