Saturday, April 1, 2023

nanokelvin microwave cooler for molecules

pte20220728019 research/development technology/digitization

Low temperature record set – MPQ researchers pave the way for new forms of quantum matter

Insight Into The Main Vacuum Chamber Of The Nak Molecule Experiment (Photo:

Insight into the main vacuum chamber of the NaK molecule experiment (Photo:

Garching (PTE019/28.07.2022/12:30)-

Researchers at the Max Planck Institute for Quantum Optics (MPQ) have developed a new microwave cooling technique for molecular gases. This makes it possible to cool polar molecules down to a few nanokelvins, which is 21 billionths of a degree above absolute zero.

evaporative cooling used

Scientists have thus set a new low-temperature record and paved the way for new forms of quantum matter that were previously experimentally inaccessible. They used a gas of sodium-potassium (NaK) molecules trapped in an optical trap by laser light. The so-called evaporative cooling was used to cool the gas.

“This method works on the same principle as a cup of hot coffee,” says MPQ researcher Shin-Yu Luo. In coffee, water molecules constantly collide and exchange part of their kinetic energy. If two particularly high-energy molecules collide, one of them may be fast enough to escape the coffee – it pops out of the cup. The second molecule has less energy left. In this way the coffee cools slowly.

energy screen brings success

In the same way, a gas can be cooled down to a few nanokelvins—a billionth of a degree from absolute zero—at minus 273.15 °C. However: “If the gas consists of molecules, these must be additionally stabilized at very low temperatures,” Luo says. To prevent this, the researchers used a trick: the additional use of a specially formulated electromagnetic field, which acts as an energetic shield for the molecules—and keeps them from clumping together and colliding.

“We created this energy screen using a strong, rotating microwave field. This field causes the molecules to spin at a high frequency,” explains Luo’s colleague Andreas Schindewolf. If two molecules get too close, they can exchange kinetic energy – but at the same time they align themselves in such a way that they repel and quickly move away from each other.

To create a microwave field with the necessary properties, the researchers placed a helical antenna under an optical trap containing a gas composed of sodium-potassium molecules. As Shin-Yu Luo reports, “the rate at which the molecules interconnected was reduced by more than an order of magnitude.” In addition, under the influence of the field, a strong and far-reaching electrical interaction developed between the molecules.


Nation World News Desk
Nation World News Desk
Nation World News is the fastest emerging news website covering all the latest news, world’s top stories, science news entertainment sports cricket’s latest discoveries, new technology gadgets, politics news, and more.
Latest news
Related news