Cool. Very Cool!
Yale physicists have published in Nature that they have created the coolest molecules ever by direct cooling – they dropped molecules of strontium monofluoride to 2.5 thousandths of a degree above absolute zero.
Temperature is essentially a measure of how vigorously particles vibrate. Absolute zero is the temperature at which all motion has completely stopped. This occurs at −273.15° on the Celsius scale and −459.67° on the Fahrenheit scale.
Researchers Barry and DeMille, et. al. used a technique known as magneto-optical trapping (MOT), which essentially uses precisely tuned lasers to push against the molecules, simultaneously slowing their movement and trapping them in place.
From the press release:
“It works this way: Pulses of strontium monofluoride (SrF) shoot out from a cryogenic chamber to form a beam of molecules, which is slowed by pushing on it with 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 slowed molecules enter a specially-shaped magnetic field, where opposing laser beams pass through the center of the field, along three perpendicular axes. This is where the molecules become trapped.”
They used strontium monofluoride because of its simple structure. It is a diatomic molecule with essentially a single electron orbiting the entire molecule.
The authors report that potential applications include precision measurement, quantum simulation, quantum information, and ultracold chemistry.