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Speaker: Victoria Xu (UCB) – Title: Broadband quantum enhancement of the LIGO detectors with frequency-dependent squeezing
April 17 @ 4:00 pm - 5:00 pm
Research Progress Meeting
Date: April 17, 2025
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Victoria Xu (UCB)
Title: Broadband quantum enhancement of the LIGO detectors with frequency-dependent squeezing
Abstract: Quantum noise imposes a fundamental limitation on the sensitivity of laser-interferometric gravitational-wave detectors like LIGO, manifesting as shot noise and quantum radiation pressure noise. We present the realization of frequency-dependent squeezing for the fourth astrophysical observing run of the LIGO detectors, resulting in the reduction of both shot noise and quantum radiation pressure noise, alongside broadband detector sensitivity enhancement from tens of hertz to several kilohertz. We further show that frequency-dependent squeezing enables astrophysical operation with quantum noise squeezed below the Standard Quantum Limit by almost 3 dB around 50 Hz, where the LIGO detectors are most astrophysically sensitive. Frequency-dependent squeezing was enabled by the addition of a 300-meter-long in-vacuum filter cavity at each detector, as part of the A+ upgrade to Advanced LIGO. For the LIGO Hanford detector, squeezing reduced the detector noise power by ~5 dB near 1 kHz; for the Livingston detector, detector noise power was reduced by ~6 dB. Combined with technical noise improvements, the quantum upgrade to frequency-dependent squeezing has expanded the detectors’ astrophysical range by almost 20% with respect to no squeezing, and thus improved astrophysical trigger rates by up to 70% during the ongoing fourth observing run of the LIGO detectors.
https://lbnl.zoom.us/j/98854322464?pwd=K2tKUm1VZjRlV1J5RHE3cXdHQzRxdz09
Meeting ID: 988 5432 2464
Passcode: 142239