Tuesday, September 13, 2011

Scientists Squeeze Lght Past Quantum Limit

The race to discover gravity waves may be getting closer to the finish line with scientists successfully squeezing light using quantum mechanics.

The detection of gravity waves is one of the Holy Grails of astronomy and astrophysics. It will allow researchers to study the inner workings of exploding stars and colliding black holes.

Einstein's general theory of relativity predicts these massive astronomical events generate tiny fluctuations, causing the fabric of space-time to expand and contract - like ripples on the surface of a pond.

These yet to be discovered waves require the most sensitive detectors ever built, but up until now they've not been sensitive enough.

Now an international team of scientists, which includes Professor David Blair, Director of the Australian International Gravity Wave Research Centre at the University of Western Australia, report on a new technique in the journal Nature Physics, which almost doubles the sensitivity of these detectors.

Blair says the GEO600 gravity wave observatory in Germany is the first practical application of this new technology, and is part of a global network called the Laser Interferometer Gravitational Wave Observatory (LIGO).

The observatory will measure tiny variations in the distance travelled by two halves of a laser beam that's been split along perpendicular arms of a kilometre-sized instrument called an interferometer.

But any the change in the beams caused by gravity waves is so tiny, it's drowned out by a quantum effect called vacuum fluctuations.

http://www.abc.net.au/science/articles/2011/09/12/3314227.htm