By Will Ferguson, College of Arts & Sciences
WSU physicists Peter Engels and Maren Mossman are part of a team studying the behavior of atoms laser-cooled to temperatures just a few billionths of a degree above absolute zero, the point where they behave like one wave of discrete particles.
On Earth, the unavoidable presence of gravity makes it difficult to conduct unperturbed observations of this this super-cooled substance – called a Bose-Einstein condensate – and the laws of quantum physics that govern its wave-like behavior.
To overcome these Earthly limitations, NASA will launch a remotely operated laser-cooling device, called the Cold Atom Laboratory (http://coldatomlab.jpl.nasa.gov/), to the International Space Station next summer.
Engels, a professor of physics, and Mossman, a graduate student researcher, will use the laboratory and the space station’s microgravity environment to create and study Bose-Einstein condensates for up to 10 seconds at a time, unlocking the potential to observe new quantum phenomena never before seen on Earth.
Their research will be the start of a new chapter in the study of quantum physics that could eventually help in the development of ultrapowerful quantum computers and a wide variety of advanced sensors for taking measurements of quantities such as gravity, rotations and magnetic fields.
“Cold atom research on the International Space Station will give us a fundamental understanding for a part of physics that is so complicated that, even with the most powerful computers on Earth, we cannot find answers,” Engels said. “Our work will, in turn, provide new insights into systems that may be important in the design of future materials and electronics like ultraprecise gravitational sensors to detect caves underground or hidden oil fields. The options are really quite limitless and exciting.”
Countdown to launch
For the last three years, Engels and Mossman have worked closely with colleagues at NASA’s Jet Propulsion Laboratory in California on the design of a laser cooling device that is not only small and durable enough to survive the tumultuous ride from Earth to the Space Station aboard a SpaceX rocket but also capable of operating remotely without maintenance. In comparison, in modern, Earth-based physics labs like Engels, laser cooling apparatus take up entire rooms and slight deviations of lasers or magnets can compromise an experiment.
The two WSU scientists are part of one of five research groups that have been running preliminary tests and computer simulations on a ground-based version of the Cold Atom Laboratory in preparation for next year’s launch.
“We are accustomed to being able to pull something out and fixing it if it breaks, which, of course, won’t be possible in space. Everything will be remotely controlled,” Mossman said. “The astronauts onboard the space station don’t have the expertise to run these kinds of experiments so we are very fortunate JPL is so good at engineering things. It is really the first time that an atomic physics experiment of this caliber is going to be installed on the space station.”
On the space station, the cold atom laboratory will use a complex array of lasers, magnetic traps, and vacuum chambers to cool clouds of rubidium and potassium atoms to temperatures colder than any naturally occurring place in the universe several hundred times a day.
The data will then be beamed down to Earth where Engels, Mossman, and their collaborators will interpret it.
Strange world of quantum physics
Normally, atoms can be imagined like billiards balls bouncing around a pool table. However, when they are super-cooled to form a Bose-Einstein condensate or when only two or three of them are isolated together, atoms and subatomic particles, like electrons, stop behaving like individual balls and start behaving like an ocean wave. This synchronized and wave-like behavior is the basis of what is known as quantum physics.
As computer chips and electronics get into regimes where the circuitry is so small it can’t be viewed with a conventional microscope, the effects of quantum physics have to be taken into account. The problem scientists will run into when trying to engineer such devices is they currently have only limited or indirect tools to study the behavior of matter at such a small scale.
“Even with our most powerful optical imaging technology, we cannot observe how two or three atoms interact,” Mossman said. “So instead, what we will be doing with the Cold Atom Laboratory is studying a much larger group of super-cooled atoms that behave in the same way and can be observed on the space station with an optical microscope. We can then transfer what we learn about this quantum mechanical weirdness to determining how a small number of atoms interact.”
News media contact:
Peter Engels, WSU Department of Physics and Astronomy, 509-335-4674, firstname.lastname@example.org