The Cold Atom Lab aboard the International Space Station is pioneering the use of quantum science in space. Recently, the lab’s scientists successfully measured subtle vibrations of the space station using ultra-cold atoms for the first time. This breakthrough was published in Nature Communications, showcasing the longest demonstration of the wave-like nature of atoms in freefall in space.
By utilizing an atom interferometer, the team was able to accurately measure gravity, magnetic fields, and other forces in space. This technology not only advances our understanding of gravity but also has the potential to enhance various technologies, from navigation systems to communication devices.
Physicists have been eager to utilize atom interferometry in space due to the extended measurement times and enhanced instrument sensitivity made possible by microgravity. Previously deemed too fragile for prolonged operation without direct assistance, the Cold Atom Lab has successfully demonstrated remote operation from Earth, proving the feasibility of using such sensitive equipment in 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.”
Space-based sensors capable of high-precision gravity measurements offer a broad spectrum of potential applications. They could, for instance, unveil the composition of planets and moons within our solar system by detecting subtle variations in gravity caused by the different densities of materials.
The U.S.-German collaboration GRACE-FO (Gravity Recovery and Climate Experiment Follow-on) is already conducting this type of measurement, detecting slight changes in gravity to track water and ice movement on Earth. An atom interferometer could enhance precision and stability, uncovering more details about surface mass changes.
Furthermore, precise gravity measurements could provide valuable insights into dark matter and dark energy, two major mysteries in cosmology. Dark matter, an invisible substance five times more abundant in the universe than “regular” matter, constitutes planets, stars, and everything visible. Dark energy is the mysterious force driving 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 new 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.”
The Cold Atom Lab, launched at the space station in 2018, aims to advance quantum science by creating a long-term facility in the microgravity environment of low Earth orbit. The lab achieves this by cooling atoms to almost absolute zero, or minus 459 degrees Fahrenheit (minus 273 degrees Celsius).
At this ultra-low temperature, some atoms form a Bose-Einstein condensate, where all atoms essentially share the same quantum identity. Consequently, some of the normally microscopic quantum properties of the atoms become macroscopic, making them easier to study.
These quantum properties include behaviors where atoms can sometimes act like solid particles and other times like waves. Scientists are leveraging quantum technology, such as that available in the Cold Atom Lab, in the quest to understand how the building blocks of all matter can transition between such disparate physical behaviors.
In the unique environment of microgravity, Bose-Einstein condensates can achieve even colder temperatures and persist for longer durations, providing scientists with increased opportunities for in-depth study. The atom interferometer, along with other advanced tools in the facility, facilitates precise measurements by leveraging the quantum properties of atoms.
Due to its wave-like characteristics, a single atom has the ability to traverse two distinct paths simultaneously. By observing how these waves recombine and interact, scientists can effectively measure the influence of gravity or other forces acting upon them.
“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.
Journal reference:
- Jason R. Williams et al. Pathfinder experiments with atom interferometry in the Cold Atom Lab onboard the International Space Station. Nature Communications, 2024; DOI: 10.1038/s41467-024-50585-6