The Cold Atom Laboratory facility that NASA has on the International Space Station has made it possible to achieve this milestone: creating the fifth state of matter . It’s been a journey of nearly two years, following that first milestone announced in July 2018 when NASA created the coldest place in space , on the ISS, in orbit around Earth.
Thanks to the weightlessness
The lack of gravity has facilitated the study of a strange quantum state of matter known as the Bose-Einstein condensate thanks to the Cold Atom Laboratory. With a temperature just a fraction of a degree above absolute zero, this lab is perfectly designed to create Bose-Einstein condensate and make these long-lasting states. And they have succeeded. NASA has announced that the first Bose-Einstein condensates have been manufactured in space.
The ability to study this strange state of matter in orbit will help scientists understand fundamental physics, as well as make new and more sensitive quantum measurements possible, as Lisa Wörner of the Institute for Quantum Technologies at the German Aerospace Center comments in Bremen. “I cannot overstate the importance of this experiment to the community.”
What is a Bose-Einstein condensate?
The Bose-Einstein condensate (BEC) is considered the fifth state of matter after the states of: plasma, solid, liquid and gas.
A Bose-Einstein condensate occurs when certain types of atoms are cooled to such low temperatures that they acquire a unified state, a super cool cloud . “It’s as if they come together and behave as a harmonious object,” clarifies physicist David Aveline of NASA’s Jet Propulsion Laboratory in Pasadena, California.
It is a peculiar state where the phenomena of quantum mechanics, which are generally microscopic, become macroscopic. They are created in magnetic traps where the atoms remain and radio frequency radiation is used to ‘evaporate’ the most energetic particles, leaving behind the cold and slow to form the condensate.
When this happens, the trap is turned off so that scientists can follow the evolution of the Bose-Einstein condensate. During this time, the condensate is said to be in free expansion, which is one of the advantages of doing this experiment in microgravity. On Earth, experiments take tens of milliseconds due to gravity, but inside the ISS, free expansion goes beyond one second, allowing for greater precision in measurements.
But act fast: the natural repulsive force between the atoms causes the super cool cloud to expand and dissipate. Hence the advantage of being weightless. This process carried out in space allows the condensate to reach lower temperatures than are possible with the same methods on Earth. In the Cold Atom Lab, rubidium atoms reached tenths of trillionths of kelvins (about 100 nanoKelvin) above absolute zero (-273 ° C).
So Bose-Einstein condensates are already the record holders for the lowest known temperature. Scientists hope that, with further improvement in cooling techniques, even colder can be achieved, with temperatures lower than those known throughout the universe.
“These experiments mark the beginning of many years of potential science operations, with additional capabilities of the instrument that will be used over time,” the authors explain in the journal Nature , which reports on the study.
The feasibility of producing cooler, more durable Bose-Einstein condensates also means that we can start to think of other ways to study them. Bose-Einstein condensed states could be used in a number of remote sensing technologies on satellites, among other things, so there is great interest in how their properties change in space.
Referencia: David C. Aveline et al. Observation of Bose–Einstein condensates in an Earth-orbiting research lab, Nature (2020). DOI: 10.1038/s41586-020-2346-1 // Maike D. Lachmann et al. Quantum matter orbits Earth, Nature (2020). DOI: 10.1038/d41586-020-01653-6
