Gravitational wave researchers go beyond the quantum limit

Scientists working at the LIGO facility in the United States, including a team from the University of Birmingham, have demonstrated how the ultra-fine tuning of the instruments enable it to push the boundaries of fundamental laws of physics. The US-based Laser Interferometer Gravitational-wave Observatory detects gravitational waves produced by catastrophic events in the universe, such as mergers of neutron stars and black holes. These space-time ripples are enabling scientists to observe gravitational effects in extreme conditions and probe fundamental questions about the universe and its history. In the core of the LIGO detectors are km-scale laser interferometers that measure the distance between 40 kg suspended mirrors with the best precision ever achieved. Typical LIGO sources - the gravitational waves - modulate the distance between the mirrors by 1/1000 of a nucleus size but are still observed with high fidelity. The unprecedented level of the LIGO sensitivity is achieved by the state-of-the-art engineering required to suppress vibrational and thermal noises in the detectors. At these levels of sensitivity, quantum mechanics starts to play an important role.