The recent study, published in 'Nature Communications' on August 13, highlights the longest demonstration of the wave-like nature of atoms in freefall while in space.

The team achieved this milestone using an atom interferometer, a quantum tool that can measure gravity, magnetic fields, and other forces with high precision. While atom interferometers have been used on Earth for studying gravity and enhancing technologies in navigation, their application in space has been limited due to the sensitivity of the equipment. However, the Cold Atom Lab, operated remotely from Earth, has now demonstrated its viability for extended use in the microgravity environment of space.

"Reaching this milestone was incredibly challenging, and our success was not always a given," said Jason Williams, the Cold Atom Lab project scientist at NASA's Jet Propulsion Laboratory in Southern California. "It took dedication and a sense of adventure by the team to make this happen."

Precision Measurement Potential
Space-based sensors capable of precise gravity measurements could unlock new insights into the composition of planets and moons, as different materials create subtle gravity variations. This kind of measurement is already being utilized by the U.S.-German GRACE-FO (Gravity Recovery and Climate Experiment Follow-on) mission to monitor water and ice movement on Earth. An atom interferometer could enhance these measurements, providing greater detail and stability in observing surface mass changes.

Additionally, precise gravity measurements could contribute to understanding dark matter and dark energy, two enigmatic components of the universe. Dark matter, an invisible substance, is believed to be five times more common than regular matter, while dark energy is thought to drive the universe's accelerating expansion.

"Atom interferometry could also be used to test Einstein's theory of general relativity in new ways," said University of Virginia professor Cass Sackett, a Cold Atom Lab principal investigator and co-author of the study. "This is the basic theory explaining the large-scale structure of our universe, and we know that there are aspects of the theory that we don't understand correctly. This technology may help us fill in those gaps and give us a more complete picture of the reality we inhabit."

A Compact Quantum Lab
Launched to the ISS in 2018, the Cold Atom Lab is about the size of a minifridge and was designed to advance quantum science by leveraging the microgravity environment of low Earth orbit. The lab cools atoms to nearly absolute zero, allowing them to form a Bose-Einstein condensate, a unique state of matter where atoms share the same quantum identity. This process makes the quantum properties of atoms, typically difficult to observe, more accessible for study.

In the microgravity of space, Bose-Einstein condensates can reach colder temperatures and last longer, offering extended opportunities for research. The atom interferometer is one of several tools in the lab that utilize the quantum nature of atoms to achieve precision measurements.

Because of their wave-like behavior, individual atoms can simultaneously traverse two separate paths. When gravity or other forces affect these waves, scientists can measure the impact by analyzing how the waves recombine and interact.

"I expect that space-based atom interferometry will lead to exciting new discoveries and fantastic quantum technologies impacting everyday life, and will transport us into a quantum future," said Nick Bigelow, a professor at the University of Rochester in New York and Cold Atom Lab principal investigator for a consortium of U.S. and German scientists who co-authored the study.

Related Links
Cold Atom Lab
Understanding Time and Space