Quantum squeezing boosts performance of LIGO and Virgo gravitational-wave detectors - Astronomy and space – Physics World10 Dec 2019, 16:04 UTC
Quantum squeezing has been used to increase the sensitivity of the LIGO and Virgo interferometers, making them better at detecting gravitational waves. The technique involves reducing the inherent uncertainty in the time at which photons arrive at detectors after travelling on round trips of several kilometres along the interferometer arms. Squeezing was implemented in April 2019 and has boosted the sensitivity of LIGO and Virgo detectors by factors of 20% and 50% respectively.
Since 2015 the two LIGO interferometers in the US – and more recently, the Virgo interferometer in Italy – have been detecting gravitational waves (ripples in spacetime) from merging pairs of black holes and neutron stars.
Each detector comprises two perpendicular interferometer arms, which are 4 km long at LIGO and 3 km at Virgo. An interferometer works by splitting laser light into two beams that travel out along the arms. The beams bounce off mirrors at the ends of the arms and return along the arms to their vertex, where the light is recombined and detected.
The LIGO and Virgo interferometers are set so that the light undergoes destructive interference at the detector, which normally measures a null signal. When a gravitational ...