JILA`s strontium optical atomic clock is now the world`s most accurate clock based on neutral atoms.

Laser Atomic Clocks could be 100 Times more Accurate

JILA`s strontium optical atomic clock is now the world`s most accurate clock based on neutral atoms.
Terrence Aym's image for:
"Laser Atomic Clocks could be 100 Times more Accurate"
Caption: JILA`s strontium optical atomic clock is now the world`s most accurate clock based on neutral atoms.
Image by: Sebastian Blatt, JILA, University of Colorado
© Public domain in the US because it is a work of the United States Federal Government.

The nature of time is a puzzle that none in physics have been able to solve. But that doesn't stop physicists from moving ahead with their ever more exacting measurement of whatever time is—and they're entering territory that makes the old-fashioned atomic clocks look like great grandpa's Model-T compared to a Ferrari fresh off the assembly line.

The quest to replace atomic clocks with nuclear clocks has been going on for more than a decade. The biggest leap the technology has taken to date taken occurred back in 2007 with the integration of lasers.

Now an international team of scientists from Geogia Tech, the University of Nevada, and the University of New South Wales, boldly suggest the creation of a revolutionary clock that would be so accurate it boggles the mind.

If such a clock, they claim, had been started at the moment of the Big Bang if would have lost less than .05 of a second during the ensuing 14 billion years.

The nuclear clock they envision employs tuned lasers nudging an atom's electrons into a precise alignment. Accomplishing such a feat, they say, would permit "seeing" past the swirling electrons and allow direct access to a targeted neutron within the heart of the atom to keep time. The technology, known as laser-pumping, as described in the 2006 white paper, "Atomic-based stabilization for laser-pumped atomic clocks."

Atomic clocks improving by factor of 10 every decade  

In December 2007, Tom O'Brian, the chief of the Time and Frequency Division of the National Institute of Standards and Technology (NIST), told that "We basically have a Moore's Law in clocks. They improve by a factor of 10 every decade."

O'Brian was interviewed about NIST's newest clock scheduled to go on line in early 2008, the NIST-F2. The F1 model replaced the old atomic clock in 1999 and the new one was touted as "an order of magnitude better."

As the technology is pushed farther ahead, NIST sees atomic clock smaller than a grain of rice and so accurate they will have to be adjusted to account for the Earth's changes in magnetic—even gravity—fields. Such permutations of energy would have relativistic effects on the clock's accuracy.

Other than splitting seconds to an incredible degree by employing colored lasers tuned to the exact frequencies of any particular atom—an accomplishment O'Brian believes feasible—the accuracy will be pushed towards measuring off 456 trillion cycles per second using a calcium atom, or 518 trillion using an atom of ytterbium.

That is the future seen by NIST's supervisory physicist of the Optical Frequency Measurements Group, Leo Hollberg.

Hollberg explained, "Each atom has its own spectral signature." That signature—or frequency—responds to coherent light waves like lasers. Each atom responds to a different light frequency. The ytterbium atom, for example, responds to the color purple.

The big dream Hollberg has is to bathe a mercury ion with finely tuned chartreuse light—the color the ion responds to—and chop a second of time into a quadrillion individual segments.

Other than the challenge and the victory of achieving something no one else has ever done, why is slicing time into such minute pieces advantageous? What benefits can doing such a thing really provide?

Scientists believe achieving such a level of accuracy will have profound applications and significant impact on future technology involving such diverse fields as medical imaging machines, geological surveying, mapping radiation and waves that affect the Earth's weather, tracking permutations in the geomagnetic field—even detecting variations in gravity waves.

Measuring minute, regional fluctuations in gravity could allow precise mapping of oil fields, water tables, and the discovery of new magma tunnels. Tracking magma movement could lead to enhanced prediction of volcanic eruptions potentially saving thousands of lives in the future.

Theoretical physicists also eye the creation of better clocks as permitting new glimpses into higher dimensions and perhaps even measuring with greater accuracy the old universe that preceded this one.

O'Brian predicts that eventually NIST will be using the next generation of laser tweaked atoms to solve some of creation's greatest mysteries.

Which mysteries in particular? asked Wired.

"Probably the interaction of space, time and gravity," O'Brian responded.

More about this author: Terrence Aym

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