LIGO and Virgo are starting the third observing run with enhanced sensitivity Squeezed light to significantly stretch the observable volume


LIGO team members install in-vacuum equipment that is part of the squeezed-light upgrade. (Image credit: LIGO/Caltech/MIT/Matt Heintze)

After nearly two years of pause, the LIGO detector in the US and the Virgo detector in Italy are resuming their quest for gravitational waves with enhanced sensitivity. In the latest upgrade of LIGO,  laser power has been doubled, five mirrors have been replaced, and a technique called quantum squeezing has been implemented that tweaks the quantum uncertainty principle to improve the sensitivity of the detectors. The observable distance is expected to increase by about 40%, leading to more than a factor of three increase in the accessible volume in the universe around our galaxy. The Virgo detector is also twice as sensitive compared to the last run. We are hoping to see many more mergers of compact binaries, which will shine more light on the formation, evolution and distribution of the densest astronomical objects and will assist in determining the correct expansion rate of the universe. We may also see new sources, like the merger of a black hole and a neutron star, or find the existence of intermediate-mass black holes which can be hundreds of times heavier than the sun. LIGO-India is expected to start operating as part of the worldwide network of detectors in 2025. Exciting times are ahead of us!

The joint press release by the LIGO-Virgo Collaboration is available here.

The LIGO-India Scientific Collaboration (LISC) consists of more than 90 members from 14 Indian institutions.