Physicists from the US have created the coldest molecules in the known Universe. The group of researchers hailing from the Massachusetts Institute of Technology (MIT) have caused a cluster of molecules to reach 500 nanokelvins, which is only 500-billionths of a degree above absolute zero (-459.67 degrees Fahrenheit, or -273.15 degrees Celsius). The findings have been published in the journal Physical Review Letters.
To achieve this, the team coupled evaporation techniques with laser technology to decrease the temperature of a sodium potassium gas to near-zero; the potassium and sodium atoms were made to glue together with the help of a magnetic field which does not otherwise normally happen. The goal was to keep motion to the minimum possible to avoid generating heat.
One laser was set to match the initial state of the molecule. A second one was tuned to be at the ultra-low temperature the scientists wanted to achieve. In this way, the molecules were drained of their energy which was them made to flow from one laser to the other. The final result occurred for around 2.5 seconds, which are deemed to be a lot by the researchers.
The scientists are positive that by cooling molecules even further and for longer time periods, they can learn more about quantum mechanical effects discussed in theories only. This might open the doors to more important scientific discoveries since molecules are more orderly at extremely low temperatures, as explains Zwierlein.
“We are very close to the temperature at which quantum mechanics plays a big role in the motion of molecules,” says Martin Zwierlein, the lead author, in a statement. “So these molecules would no longer run around like billiard balls, but move as quantum mechanical matter waves. And with ultracold molecules, you can get a huge variety of different states of matter, like superfluid crystals, which are crystalline, yet feel no friction, which is totally bizarre. This has not been observed so far, but predicted. We might not be far from seeing these effects, so we’re all excited.”
He also added: “Now we’re at 500 nanokelvins, which is already fantastic, we love it. A factor of 10 colder or so, and the music starts playing.”