Researchers at JILA, a US research institute, have developed an exact light-based atomic clock.
Conventional atomic clocks use microwaves to calculate a second’s duration. However, because visible light waves have a higher frequency than other types of light, recent developments have proven that employing visible light can achieve far higher accuracy. Compared to their microwave equivalents, optical atomic clocks, which use light, could be precise to within one second over a period of 30 billion years. However, clocks that can measure extremely small fractions of a second are necessary to achieve such precision.
Researchers at JILA have developed a breakthrough technique that allows them to monitor tens of thousands of atoms at once: an optical lattice, or web of light. This method yields additional data to the atomic clock, enabling incredibly accurate time measurements. Although the optical lattice method is not new per se, JILA’s more gentle approach reduces two crucial sources of error: interactions between tightly packed atoms and laser-induced atoms.
This exact clock can measure the submillimeter-scale effects of gravity on timekeeping, which is consistent with Einstein’s general theory of relativity. The hypothesis states that in higher gravitational fields, time slows down. The JILA clock has shown this by detecting minute variations in time intervals when the clock’s location is shifted. “It’s pushing the boundaries of what’s possible with timekeeping,” said Jun Ye, a physicist at JILA and NIST.
The implications of this clock extend beyond general relativity into the quantum realm. Quantum computers manipulate atomic and molecular properties for complex computations. With its precise measurements, the JILA clock can explore the intersection of general relativity and quantum mechanics, observing time distortions caused by gravity at microscopic scales.
Additionally, the clock’s precision is expected to revolutionize space navigation. “If we want to land a spacecraft on Mars with pinpoint accuracy, we’re going to need clocks that are orders of magnitude more precise than what we have today in GPS,” Ye added.
JILA, a joint institute of the University of Colorado Boulder and the National Institute of Standards and Technology (NIST), keeps pushing the boundaries of measurement science. “We’re exploring the frontiers of measurement science; when you can measure things with this level of precision, you start to see phenomena that we’ve only been able to theorize about until now,” Ye said.
The research findings from JILA’s work will be published in the journal Physical Review Letters.
