PartagerLes molécules les plus froides jamais obtenues (en anglais)
Des physiciens de l'Université de Yale affirment avoir obtenu les molécules les plus froides jamais obtenues par refroidissement direct.
Physicists at Yale University claim to have achieved the coldest ever molecules through direct cooling.
The tiny titans in question are bits of strontium monofluoride, dropped to 2.5 millikelvin degree above absolute zero through a laser cooling and isolating process called magneto-optical trapping (MOT). They are said to be the coldest molecules ever achieved through direct cooling, and they represent a physics milestone likely to prompt new research in areas ranging from quantum chemistry to tests of the most basic theories in particle physics.
According to Dave DeMille, a Yale physics professor and principal investigator, they can allow for the study of chemical reactions that occur very near to absolute zero and give us a chance to learn about fundamental chemical mechanisms.
DeMille and his colleagues built their own apparatus in a basement lab. It is an elaborate, multi-level tangle of wires, computers, electrical components, tabletop mirrors, and a cryogenic refrigeration unit. The process uses a dozen lasers, each with a wavelength controlled to the ninth decimal point.
It operates as follows: pulses of strontium monofluoride (SrF) shoot out from a cryogenic chamber to form a beam of molecules, which is slowed by pushes from a laser. 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.
“Quantum mechanics allows us to both cool things down and apply force that leaves the molecules levitating in an almost perfect vacuum,” DeMille said.
The Yale team chose SrF for its structural simplicity: it has effectively just one electron that orbits around the entire molecule.
The discovery opens the door for further experimentation into everything from precision measurements and quantum simulations to ultracold chemistry and tests of the standard model of particle physics.
The tiny titans in question are bits of strontium monofluoride, dropped to 2.5 millikelvin degree above absolute zero through a laser cooling and isolating process called magneto-optical trapping (MOT). They are said to be the coldest molecules ever achieved through direct cooling, and they represent a physics milestone likely to prompt new research in areas ranging from quantum chemistry to tests of the most basic theories in particle physics.
According to Dave DeMille, a Yale physics professor and principal investigator, they can allow for the study of chemical reactions that occur very near to absolute zero and give us a chance to learn about fundamental chemical mechanisms.
DeMille and his colleagues built their own apparatus in a basement lab. It is an elaborate, multi-level tangle of wires, computers, electrical components, tabletop mirrors, and a cryogenic refrigeration unit. The process uses a dozen lasers, each with a wavelength controlled to the ninth decimal point.
It operates as follows: pulses of strontium monofluoride (SrF) shoot out from a cryogenic chamber to form a beam of molecules, which is slowed by pushes from a laser. 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.
“Quantum mechanics allows us to both cool things down and apply force that leaves the molecules levitating in an almost perfect vacuum,” DeMille said.
The Yale team chose SrF for its structural simplicity: it has effectively just one electron that orbits around the entire molecule.
The discovery opens the door for further experimentation into everything from precision measurements and quantum simulations to ultracold chemistry and tests of the standard model of particle physics.