Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Quantum goes massive

20.07.2009
An astrophysics experiment in America has demonstrated how fundamental research in one subject area can have a profound effect on work in another as the instruments used for the Laser Interferometer Gravitational-Wave Observatory (LIGO) pave the way for quantum experiments on a macroscopic scale.

The work is reported in a research article published today, Thursday, 16 July, in New Journal of Physics (co-owned by the Institute of Physics and German Physical Society). It can be found at http://stacks.iop.org/NJP/11/073032.

LIGO is a huge experiment, funded mainly by the U.S. National Science Foundation and involving more than 600 astrophysicists worldwide, undertaken to detect gravitational waves and thereby help us monitor space through another valuable set of lenses - gravitational radiation.

By measuring tiny motions of test masses caused by passing gravitational waves, LIGO expects to directly detect this radiation, thought to stem from exotic phenomena in space such as the collisions of neutron stars and black holes, and supernovae.

Laser light is used to monitor relative displacements of interferometer mirrors, which are suspended as pendulums to act as quasi-free test masses. Since the effect of gravitational waves is expected to be very small, LIGO detectors are sensitive enough to measure displacements smaller than one-thousandth the size of a proton for mirrors that are 4 km apart.

In different frequency bands, the sensitivity of the LIGO instruments are limited by noise arising from the quantum nature of the laser light, or by thermal noise arising from the thermal energy of the mirrors. Observing quantum mechanical behaviour of the LIGO mirrors requires reducing the thermal noise, which may be achieved by cooling the interferometer mirrors with techniques similar to laser cooling of atoms. However, the temperature must be brought extremely close to absolute zero (0 Kelvin, or about -273 degrees Celsius).

While absolute zero is impossible to achieve, scientists working on LIGO have used both a frictionless damping force and a magnetic restoring force to cool the mirror oscillator to about 1 millionth of a degree above absolute zero. The frictionless damping force removes energy from the mirror while the restoring force increases the frequency of the oscillator in order to avoid disturbances caused by local ground motion.

While the effort to detect gravitational waves is ongoing, the researchers have now used the LIGO apparatus to observe the oscillations of a 2.7 kg pendulum mode at a level close to its quantum ground state. The results suggest that it should be possible for quantum physicists to use the apparatus to observe quantum mechanical behaviour, such as quantum entanglement, at mass scales previously thought impractical.

While there is still work to go in strengthening the laser and reducing excess noise in the detectors, LIGO scientists Thomas Corbitt and Nergis Mavalvala of the Massachusetts Institute of Technology echo the optimism of the research article, which concludes that "the present work, reaching Microkelvin temperatures, provides evidence that interferometric gravitational wave detectors, designed as sensitive probes of general relativity and astrophysical phenomena, can also become sensitive probes of macroscopic quantum mechanics."

Joe Winters | EurekAlert!
Further information:
http://www.iop.org

More articles from Physics and Astronomy:

nachricht A 100-year-old physics problem has been solved at EPFL
23.06.2017 | Ecole Polytechnique Fédérale de Lausanne

nachricht Quantum thermometer or optical refrigerator?
23.06.2017 | National Institute of Standards and Technology (NIST)

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>