Frequency-dependent squeezing for gravitational-wave detection through quantum teleportation

Ground-based interferometric gravitational-wave detectors are highly precise sensors for weak forces, limited in sensitivity across their detection band by quantum fluctuations of light. Current and future instruments address this limitation by injecting frequency-dependent squeezed vacuum into the detection port, utilizing narrow-band, low-loss optical filter cavities for optimal rotation of the squeezing ellipse at each signal frequency. This study introduces a scheme of such vacuum injection employing the principles of quantum teleportation which works the same as an arbitrary number of filter cavities without additional kilometer-scale infrastructure. We applied this scheme to a detuned signal-recycled Fabry-P\'erot--Michelson interferometer, which is the baseline design of the low-frequency detector within the Einstein Telescope xylophone detector. It is shown that our scheme achieves broadband suppression of quantum noise without requiring additional filter cavities or modifications to the core optics of the main interferometer.