Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Measurements may help show if constants are changing

02.05.2006


Physicists at JILA have performed the first-ever precision measurements using ultracold molecules, in work that may help solve a long-standing scientific mystery--whether so-called constants of nature have changed since the dawn of the universe.

The research, reported in the April 14 issue of Physical Review Letters,* involved measuring two phenomena simultaneously--electron motion, and rotating and vibrating nuclei--in highly reactive molecules containing one oxygen atom and one hydrogen atom. The researchers greatly improved the precision of these microwave frequency measurements by using electric fields to slow down the molecules, providing more time for interaction and analysis. JILA is a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder.

Compared to the previous record, set more than 30 years ago, the JILA team improved the precision of one frequency measurement 25-fold and another 10-fold. This was achieved by producing pulses of cold molecules at various speeds, hitting each group with a microwave pulse of a selected frequency, and then measuring how many molecules were in particular energy states. The apparatus and approach were similar to those used in the NIST-F1 cesium atomic fountain clock, the nation’s primary time standard, raising the possibility of designing a clock that keeps time with molecules, instead of atoms.



The JILA team’s ability to make two molecular measurements at once enables scientists to apply mathematical calculations to probe the evolution over time of fundamental natural properties such as the fine structure constant, which is widely used in research to represent the strength of electromagnetic interactions. Another research group at the National Radio Astronomy Observatory plans to make similar frequency measurements soon of the same molecules produced in distant galaxies, which are so far from Earth that they represent a window into ancient history. By comparing precision values for the fine structure constant on Earth and in distant parts of the universe, scientists hope to determine whether this constant has changed over 10 billion years. Because the fine structure constant is used in so many fields of physics, these measurements are a way to test the consistency of existing theories. The JILA measurements could enable any change in the fine structure constant over time to be determined with a precision of one part per million.

Laura Ost | EurekAlert!
Further information:
http://www.nist.gov

More articles from Physics and Astronomy:

nachricht MSU astronomers discovered supermassive black hole in an ultracompact dwarf galaxy
14.08.2018 | Lomonosov Moscow State University

nachricht ASU astrophysicist helps discover that ultrahot planets have starlike atmospheres
13.08.2018 | Arizona State University

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: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

Im Focus: World record: Fastest 3-D tomographic images at BESSY II

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

'Building up' stretchable electronics to be as multipurpose as your smartphone

14.08.2018 | Information Technology

During HIV infection, antibody can block B cells from fighting pathogens

14.08.2018 | Life Sciences

First study on physical properties of giant cancer cells may inform new treatments

14.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>