Researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) have made a groundbreaking advancement by overcoming quantum noise that obscures gravitational waves, leading to a nearly doubled detection rate of cosmic events.
Quantum noise, a limiting factor for detectors, is caused by minute fluctuations in space-time. LIGO, which detects gravitational waves produced by significant cosmic events like black hole collisions, utilizes laser beams along two perpendicular 4-kilometer-long arms. Variations in space-time caused by passing gravitational waves result in tiny differences in the distances traveled by these beams.
To enhance detection, researchers altered the quantum properties of the laser light, minimizing interruptions from quantum fluctuations. They integrated devices such as special crystals, lenses, and mirrors to manipulate the light into a state that reduces flickering, allowing for clearer gravitational wave signals.
After implementing this “squeezed light” technique during its initial run in 2020, LIGO previously faced challenges at lower frequencies. However, the researchers refined this process to ensure optimal performance across all frequencies before LIGO’s 2023 run. As a result, the number of detected gravitational waves dramatically increased, expanding the machine’s observational capacity.
Experts believe this advancement in precision measurement will allow LIGO to observe black hole mergers dating back to the formation of the first stars. The improved sensitivity also opens avenues for discovering new types of gravitational waves, particularly those from rotating neutron stars, which have not been the primary focus of past detections.
With each enhancement in detector sensitivity, the likelihood of uncovering unexpected phenomena grows, paving the way for exciting new discoveries in the field of astrophysics.
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