(NIST: Gaithersburg, MD) -- In a paradox typical of the quantum world, scientists at JILA, a joint institute of the University of Colorado at Boulder and the National Institute of Standards and Technology (NIST), have eliminated collisions between atoms in an atomic clock by packing the atoms closer together. The surprising discovery, described in the Feb. 3 issue of Science Express, can boost the performance of experimental atomic clocks made of thousands or tens of thousands of neutral atoms trapped by intersecting laser beams.

Such clocks work by using the interaction of light from lasers and magnetic fields with atoms to “cool” the atoms until they are almost motionless and hold them in small regions defined by the light beams, a technique called optical trapping. The devices provide highly accurate time by measuring oscillations (which serve as “ticks”) between the energy levels in the atoms. Things that perturb or alter those energy levels, such as collisions, limit the accuracy of the clocks.

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