The LIGO Scientific Collaboration has successfully implemented a noise-squeezing technique across the full spectrum of gravitational-wave frequencies detectable by their instruments, potentially increasing the detection of black hole mergers by up to 65%. This technique, known as frequency-dependent squeezing, optimizes noise reduction for different frequencies by employing a 300-meter-long filter cavity. This innovation allows for amplitude squeezing at low frequencies and phase squeezing at high frequencies, effectively countering the limiting quantum noise in each band.
Gravitational-wave detectors like LIGO are highly sensitive, able to discern distortions smaller than a proton’s size caused by passing gravitational waves. However, quantum noise, mainly from vacuum photon fluctuations, has been a significant challenge. The new squeezing technique, which manipulates the quantum state of light, can minimize this noise, thereby enhancing the detectors’ sensitivity.
Testing this technique showed improved performance across all frequencies, with significant benefits below 300 Hz where radiation-pressure noise was previously problematic. The improved sensitivity is estimated to increase the observable volume of the universe by 65%, enabling LIGO to detect more mergers and observe them with higher signal-to-noise ratios. This could lead to a better understanding of the formation of compact objects and the testing of general relativity, possibly uncovering new physics.
Experts believe this advancement is a significant step towards the goals of future gravitational-wave interferometers like the Cosmic Explorer and the Einstein Telescope, which aim for a tenfold increase in noise squeezing power. Minimizing optical losses is a crucial next step, and the LIGO team’s understanding of these losses positions them well for future improvements.
Key Takeaways:
- The LIGO Scientific Collaboration has enhanced gravitational-wave detection by employing a sophisticated noise-squeezing technique that increases the observable volume of the universe by 65%.
- Frequency-dependent squeezing allows LIGO to minimize quantum noise across its entire detectable frequency range, improving the detection of faint gravitational waves from celestial events.
- Advancements in noise reduction techniques are expected to expand the catalogue of observable black hole and neutron star mergers, providing deeper insights into the formation of these cosmic phenomena.
“The LIGO Scientific Collaboration has demonstrated a noise-squeezing technique for the entire range of gravitational frequencies LIGO can detect—a feat that could boost the detection rate of black hole mergers by up to 65%.”
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