Physicists have measured and controlled seemingly forbidden collisions between neutral strontium atoms—a class of antisocial atoms known as fermions that are not supposed to collide when in identical energy states. The advance makes possible a significant boost in the accuracy of atomic clocks based on hundreds or thousands of neutral atoms. Described in the April 17 issue of the journal Science the research was performed at JILA a joint institute of the National Institute of Standards and Technology NIST and the University of Colorado CU at Boulder. “This is one of the most precise measurements of collisional effects in a clock ” says NIST JILA Fellow Jun Ye whose strontium atomic clock design enables scientists to “peek into very tiny effects.” The new techniques make JILA s strontium clock 50 percent more accurate than the results reported last year so that it now would neither gain nor lose 1 second in more than 300 million years. The method could also be applicable to many other atomic clocks based on neutral atoms.
– via sciencedaily