Yale researchers created the "world's coolest molecules."
The research team dropped bits of mstrontium monofluoride to 2.5 thousandths of a degree above absolute zero using a laser cooling and isolating process dubbed magneto-optical trapping (MOT). The result was the coldest molecules ever created through direct cooling methods and could open up the door for new research opportunities.
"We can start studying chemical reactions that are happening at very near to absolute zero," said Dave DeMille, a Yale physics professor and principal investigator. "We have a chance to learn about fundamental chemical mechanisms."
The method works by cooling down the particles while holding them in place.
"Imagine having a shallow bowl with a little molasses in it," DeMille said. "If you roll some balls into the bowl, they will slow down and accumulate at the bottom. For our experiment, the molecules are like the balls and the bowl with molasses is created via laser beams and magnetic fields."
In the past the rotation of these molecules made it too difficult to capture them in this way. In order to remedy this the researchers built their own apparatus in a basement lab; the device boasts a dozen lasers with the wavelength controlled to the ninth decimal point. In the method pulses of strontium monofluoride (SrF) are released from a cryogenic chamber to form a "beam" of molecules which is slowed by a laser.
"It's like trying to slow down a bowling ball with ping pong balls," DeMille explained. "You have to do it fast and do it a lot of times."
The molecules then enter a magnetic field in which opposing laser beams pass through the center and trap the molecules. The team chose SrF because it has a simple structure consisting of one electron orbiting the entire molecule.
The new discovery will allow for experiments that were not previously possible in fields such as precision measurement and quantum simulation.
The findings were published this week in the journal Nature
