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 New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center

nachricht Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology

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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>