. 24/7 Space News .
A Quantum Mechanical Tune Up For Better Measurement

in the real world there will always be plenty of time

 Washington (SPX) Jun 07, 2004
By exploiting the weird quantum behavior of atoms, physicists at the Commerce Department's National Institute of Standards and Technology (NIST) have demonstrated a new technique that someday could be used to save weeks of measurements needed to operate ultraprecise atomic clocks. The technique also could be used to improve the precision of other measurement processes such as spectroscopy.

The technique, described in today's issue of Science, effectively turns atoms into better frequency sensors. Eventually, the technique could help scientists measure the ticks of an atomic clock faster and more accurately. Just as a grandfather clock uses the regular swings of a pendulum to count off each second of time, an atomic clock produces billions of ticks per second by detecting the regular oscillations of atoms. The trick to producing extremely accurate atomic clocks is to measure this frequency very precisely for a specific atom.

In the latest experiment, the scientists used very brief pulses of ultraviolet light in a NIST-developed technique to put three beryllium ions (charged atoms) into a special quantum state called entanglement. In simple terms, entanglement involves correlating the fates of two or more atoms such that their behavior-in concert-is very different from the independent actions of unentangled atoms.

One effect is that, once a measurement is made on one atom, it becomes possible to predict the result of a measurement on another. When applied to atoms in an atomic clock, the effect is that n entangled atoms will tick n times faster than the unentangled atoms.

Currently, scientists at NIST and other laboratories make many thousands of measurements of the ticks of unentangled atoms and average these results to get highly accurate atomic clocks (currently keeping time to better than one second in 40 million years).

If entangled atoms could be used in a clock, the same or better results could be achieved with far fewer separate measurements. The current experiment demonstrates this new approach to precision measurement with three ions; however, the researchers are looking forward to entangling even more ions to take greater advantage of the technique.

"Even if we could implement this new technique with only 10 ions, in the clock business that's really important because the clocks must be averaged for weeks and even months," says NIST physicist Dave Wineland, leader of the research group. "The time needed to do that would be reduced by a factor of 10."

In the experiment reported in Science, scientists entangled the ions with two laser beams, using a technique originally developed for quantum computing applications. The ions are hit with another series of laser pulses and their fluorescence (emitted light, which represents the ions' quantum state) is measured for a specific period of time.

The duration of the steps, number of ions, and other experimental conditions are controlled carefully to ensure all the ions are in the same state when they are measured, so that either all or none fluoresce, which simplifies the readout.

Related Links
NIST
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express



Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


Charting The Giants
Garching (SPX) Jun 04, 2004
Clusters of galaxies are very large building blocks of the Universe. These gigantic structures contain hundreds to thousands of galaxies and, less visible but equally interesting, an additional amount of "dark matter" whose origin still defies the astronomers, with a total mass of thousands of millions of millions times the mass of our Sun.







  • ESA At The Universal Forum Of Culture
  • Historic Space Launch Attempt Scheduled For June 21
  • Historic Space Launch Attempt Scheduled For June 21
  • Jet Models Will Push The Envelope For Safety's Sake

  • Surveyor Clocks Up 25,000 Global Circuits Of Mars
  • First Stop Gusev
  • On The Road Mars Style
  • Setting Twin Sights

  • NASA Releases Requirements For Proposed Jupiter Mission
  • Orbital Launches Taiwan's ROCSAT-2 Aboard Taurus XL
  • Optus D1 - Groundbreaking Contract
  • ILS Successfully Launches AMC-11 Satellite; Celebrates 5 Missions in 5 Months

  • The Good, The Bad And The Ozone
  • ITT Industries Awarded Next Generation GOES Weather Satellite
  • Continents Played Key Role In Collapse And Regeneration Of Earth's Early Greenhouse
  • A "Swarm" Of Satellites For A Unique Look Inside The Earth

  • Hubble Fails To Spot Suspected Sedna Moon
  • Life Beneath The Ice In The Outer Solar System?
  • Gravity Rules: The Nature of Planethood
  • Enigma Of Uranus Solved At Last

  • SMART-1 Finds Small Thrust Level Oscillations Help
  • China's Lunar Probe Will Launch On Long March 3A
  • Cornell Astronomer Explains To Congress The Economics Of Lunar Water Supplies
  • Arizona Planetary Scientists Call For Lunar Exploration

  • New Moon Shot Not So Costly
  • Armstrong Reflects On A New Visions For Space Exploration
  • Sunny lunar mountain good site for base
  • Lunar Convoys As An Option For A Return To The Moon

  • US Xpress Contracts With Qualcomm For OmniTRACS Mobile Solution
  • Antaris GPS Receiver Has First Fix In Four Seconds
  • Stanford Engineers Create GPS Steering
  • Trimble and u-Nav To Develop Next Level of GPS for Portable Electronics

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement