It's official. Yale physicists have chilled the world's coolest molecules.
The tiny titans in question are bits of strontium monofluoride, dropped to 2.5 thousandths of a degree above absolute zero through a laser cooling and isolating process called magneto-optical trapping (MOT).
They are 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.
"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 research is published this week in the journal Nature.
Magneto-optical trapping has become ubiquitous among atomic physicists in the past generation — but only at the single-atom level. The technology uses lasers to simultaneously cool particles and hold them in place. "Imagine having a shallow bowl with a little molasses in it," DeMille explained. "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."
Until now, the complicated vibrations and rotations of molecules proved too difficult for such trapping. The Yale team's unique approach drew inspiration from a relatively obscure, 1990s research paper that described MOT-type results in a situation where the usual cooling and trapping conditions were not met.
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.
"If you wanted to put a picture of something high-tech in the dictionary, this is what it might look like," DeMille said. "It's deeply orderly, but with a bit of chaos."
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.
"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. "We thought it would be best to start applying this technique with a simple diatomic molecule," DeMille said.
The discovery opens the door for further experimentation into everything from precision measurement and quantum simulation to ultracold chemistry and tests of the standard model of particle physics.
The lead author of the paper is John Barry, a former Yale graduate student now at the Harvard-Smithsonian Center for Astrophysics. Other authors of the paper are Yale postdoctoral fellow Danny McCarron and graduate students Eric Norrgard and Matt Steinecker.
Jim Shelton | Eurek Alert!
Astronomers discover dizzying spin of the Milky Way galaxy's 'halo'
26.07.2016 | NASA/Goddard Space Flight Center
Lonely Atoms, Happily Reunited
26.07.2016 | Technische Universität Wien
Transparent electronics devices are present in today’s thin film displays, solar cells, and touchscreens. The future will bring flexible versions of such devices. Their production requires printable materials that are transparent and remain highly conductive even when deformed. Researchers at INM – Leibniz Institute for New Materials have combined a new self-assembling nano ink with an imprint process to create flexible conductive grids with a resolution below one micrometer.
To print the grids, an ink of gold nanowires is applied to a substrate. A structured stamp is pressed on the substrate and forces the ink into a pattern. “The...
A new Fraunhofer MEVIS method conveys medical interrelationships quickly and intuitively with innovative visualization technology
On the monitor, a brain spins slowly and can be examined from every angle. Suddenly, some sections start glowing, first on the side and then the entire back of...
Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.
While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.
Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.
Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...
Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases
Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...
15.07.2016 | Event News
15.07.2016 | Event News
11.07.2016 | Event News
27.07.2016 | Earth Sciences
27.07.2016 | Materials Sciences
27.07.2016 | Earth Sciences