The world’s most accurate atomic clock

Scientists at the US research institute JILA have developed a new type of optical atomic clock so precise that it can measure the smallest impacts predicted by Einstein’s general theory of relativity. This clock could help define a second more precisely, leading to the discovery of new underground mineral deposits, Interesting Engineering July 2 news.

Atomic clocks typically use microwaves to measure the length of a second. However, research shows that shining visible light on atoms can help count seconds more accurately because the light waves have a higher frequency. Optical atomic clocks can lose one second every 30 billion years compared to microwave clocks. However, to achieve this level of accuracy, the clock needs to measure tiny fractions of a second.

Instead of using a beam of visible light, the JILA team used a network of lights called an optical lattice to measure tens of thousands of atoms at once. This gives the atomic clock more data to measure a second accurately. While optical lattice methods have been used before, the JILA researchers performed the measurements in a relatively new way, reducing two sources of error: the lasers that measure the atoms and the impact of atoms crashing into each other as they are squeezed together.

According to Einstein’s general theory of relativity, gravity affects time. Strong gravitational fields slow down the flow of time. The clock developed by JILA is sensitive enough to measure the effects of gravity on timekeeping at submillimeter levels.

Quantum computers rely on the properties of atoms and molecules to perform complex calculations. Because the JILA clock can measure so precisely, the team plans to use it in the microscopic realm, where general relativity intersects with quantum mechanics, to measure changes in the flow of time due to the influence of gravity. At the same time, the clock’s precision could help scientists keep time across vast distances in space. “If we want to land a spacecraft on Mars accurately, we need a clock that is many times more precise than the GPS system,” said Jun Ye, a physicist at JILA.

JILA is a joint institute of the US National Institute of Standards and Technology (NIST) and the University of Colorado Boulder. The research team will publish their findings in the journal Physical Review Letters.