Researchers have built an atomic clock that is more accurate and precise than any previous one. For the first time, it can detect the effects of gravity predicted by the general theory of relativity on a microscopic scale. The clock is the latest evidence that a more precise definition of the second gear is possible and that new applications for clocks are possible.
World’s most accurate atomic clock opens new horizons in physics
In humanity’s relentless pursuit of perfection, scientists have developed an atomic clock that is more accurate and precise than any previously created. The new clock was built by researchers at JILA, a joint venture between the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder.
Capable of enabling precise navigation across the vast expanses of space, as well as searching for new molecules, this latest technology goes beyond simply measuring time. With its increased precision, these next-generation watches could uncover hidden mineral deposits underground and test fundamental theories like general relativity with unprecedented precision. For atomic clock engineers, it’s not just about building a better clock; it’s about unlocking the secrets of the universe and paving the way for technologies that will shape our world for generations to come.
Redefining the second
The global scientific community is considering redefining the second, the international unit of time, based on the next generation of optical atomic clocks. Current atomic clocks use microwaves to measure the second by illuminating atoms. This new generation of clocks illuminates atoms with much higher frequency visible light waves, allowing the second to be measured with greater precision. Compared to current microwave clocks, optical clocks are expected to provide much greater accuracy for measuring international time, potentially losing only one second every 30 billion years.
But before these atomic clocks can operate with such high precision, they need to be very precise; in other words, they need to be able to measure very small fractions of a second. Achieving high precision and high accuracy could have far-reaching implications.
caught up in time
The new JILA clock uses a network of light known as an “optical grid” to trap and measure tens of thousands of individual atoms at once. Having such a large array provides a huge advantage in accuracy. The more atoms measured, the more data the clock needs to get an accurate measurement to the second.
To achieve record performance, the JILA researchers used a thinner, softer “lattice” of laser light to trap the atoms than previous optical lattice clocks. This dramatically reduced two major sources of error: the effects of laser light trapping the atoms and the collisions of the atoms with each other when they are too close together.
Researchers describe their progress in Physical Review Letters.
Measuring relativity on the smallest scales
This clock is so precise that it can detect tiny effects predicted by theories like general relativity, even at the microscopic level. It pushes the boundaries of what is possible in measuring time.
John Ye, a physicist at NIST and JILA.
General relativity is Einstein’s theory that describes how gravity is produced by warping space and time. One of the main predictions of general relativity is that time itself is affected by gravity: the stronger the gravitational field, the slower time passes.
This new clock design could allow researchers to detect relativistic effects in timekeeping on a sub-millimeter scale, roughly the thickness of a human hair. Raising or lowering the clock by this small distance is enough for researchers to notice a small change in the flow of time caused by gravitational effects.
This ability to observe the effects of general relativity at the microscopic level could significantly bridge the gap between the microscopic quantum world and the large-scale phenomena described by general relativity.
Space navigation and quantum progress
More accurate atomic clocks also allow for more precise navigation and exploration in space. As humans move deeper into the solar system, clocks will need to keep accurate time across vast distances. Even small errors in timing can lead to navigation errors that grow exponentially the farther you travel.
If we want to land a spacecraft on Mars with millimeter accuracy, we will need clocks that are more accurate than those in today’s GPS system. This new clock is an important step toward achieving that.
John Yee
The same techniques used to trap and control atoms could also lead to advances in quantum computing. Quantum computers must be able to precisely manipulate the internal properties of individual atoms or molecules to perform calculations. Advances in controlling and measuring microscopic quantum systems have led to significant advances in this effort.
By venturing into the microscopic world where the theories of quantum mechanics and general relativity intersect, researchers are opening the door to new levels of understanding about the fundamental nature of reality itself. From the infinitesimal scales where the flow of time is distorted by gravity, to the vast cosmic frontiers where dark matter and dark energy are at work, the exquisite precision of this watch promises to shed light on some of the deepest mysteries of the universe.
We’re exploring the frontiers of metrology. When you can measure things with this level of precision, you start to see phenomena that we’ve only been able to theorize until now.
John Yee
via www.nist.gov
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