QUROPE Quantum Information Processing and Communication in Europe

J. Aasi, et al.
Nature Photonics 7, 613–619 (2013)

A global network of observatories is seeking to directly detect gravitational waves using precision laser
interferometry. Photon shot noise, due to the quantum nature of light, imposes a fundamental limit on the
attometre-level sensitivity of the kilometre-scale Michelson interferometers deployed for this task.

In their work, Aasi and colleagues report the use of squeezed light to enhance the sensitivity of the Laser
Interferometer Gravitational-Wave Observatory (LIGO). This is both an exciting advance for gravitational
research, and the first time that non-classical states of light have been shown to provide a genuine and
significant enhancement in the performance of a real (and in this case, cutting edge) measurement, over what
is possible with classical optical metrology.