The ultra-stable ytterbium lattice atomic clock.
WASHINGTON: US scientists say they have built the world’s most precise clock, whose ticking rate varies less than two parts in one quintillion, or 10 times better than any other.
The clock, made from the element ytterbium, could be used for technological advancements beyond timekeeping, such as navigation systems, magnetic fields and temperature.
While mechanical clocks use the movement of a pendulum to keep time, atomic clocks use an electromagnetic signal of light emitted at an exact frequency to move electrons in cesium atoms.
The physicists built their ytterbium clocks using about 10,000 rare-earth atoms cooled to 10 microkelvin (10 millionths of a degree above absolute zero) and trapped in an optical lattice made of laser light.
Another laser that “ticks” 518 trillion times per second triggers a transition between two energy levels in the atoms. The clock’s high stability is owed to the large number of atoms.
Technicians must average the current US civilian time standard, the National Institute of Standards and Technology-F1 caesium fountain clock, for about 400,000 seconds (about five days) to obtain its best performance.
AFP
