From NASA/JPL at Caltech: “Cold Atom Laboratory Chills Atoms to New Lows”

JPL

September 26, 2014
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau@jpl.nasa.gov

NASA’s Cold Atom Laboratory (CAL) mission has succeeded in producing a state of matter known as a Bose-Einstein condensate, a key breakthrough for the instrument leading up to its debut on the International Space Station in late 2016.

>NASA’s Cold Atom Laboratory

A Bose-Einstein condensate (BEC) is a collection of atoms in a dilute gas that have been lowered to extremely cold temperatures and all occupy the same quantum state, in which all of the atoms have the same energy levels. At a critical temperature, atoms begin to coalesce, overlap and become synchronized like dancers in a chorus line. The resulting condensate is a new state of matter that behaves like a giant — by atomic standards — wave.

“It’s official. CAL’s ground testbed is the coolest spot at NASA’s Jet Propulsion Laboratory at 200 nano-Kelvin [200 billionths of 1 Kelvin], “said Cold Atom Laboratory Project Scientist Rob Thompson at JPL in Pasadena, California. “Achieving Bose-Einstein condensation in our prototype hardware is a crucial step for the mission.”

Although these quantum gases had been created before elsewhere on Earth, the Cold Atom Laboratory will explore the condensates in an entirely new regime: The microgravity environment of the space station. It will enable groundbreaking research in temperatures colder than any found on Earth.

CAL will be a facility for studying ultra-cold quantum gases on the space station. In the station’s microgravity environment, interaction times and temperatures as low as one picokelvin (one trillionth of one Kelvin, or 293 trillion times below room temperature) should be achievable. That’s colder than anything known in nature, and the experiments with CAL could potentially create the coldest matter ever observed in the universe. These breakthrough temperatures unlock the potential to observe new quantum phenomena and test some of the most fundamental laws of physics.

First observed in 1995, Bose-Einstein condensation has been one of the “hottest” topics in physics ever since. The condensates are different from normal gases; they represent a distinct state of matter that starts to form typically below a millionth of a degree above absolute zero, the temperature at which atoms have the least energy and are close to motionless. Familiar concepts of “solid,” “liquid” and “gas” no longer apply at such cold temperatures; instead, atoms do bizarre things governed by quantum mechanics, such as behaving as waves and particles at the same time.

Cold Atom Laboratory researchers used lasers to optically cool rubidium atoms to temperatures almost a million times colder than that of the depths of space. The atoms were then magnetically trapped, and radio waves were used to cool the atoms 100 times lower. The radiofrequency radiation acts like a knife, slicing away the hottest atoms from the trap so that only the coldest remain.

The research is at the point where this process can reliably create a Bose-Einstein condensate in just seconds.

“This was a tremendous accomplishment for the CAL team. It confirms the fidelity of the instrument system design and provides us a facility to perform science and hardware verifications before we get to the space station,” said CAL Project Manager Anita Sengupta of JPL.

While so far, the Cold Atom Laboratory researchers have created Bose-Einstein condensates with rubidium atoms, eventually they will also add in potassium. The behavior of two condensates mixing together will be fascinating for physicists to observe, especially in space.

Besides merely creating Bose-Einstein condensates, CAL provides a suite of tools to manipulate and probe these quantum gases in a variety of ways. It has a unique role as a facility for the atomic, molecular and optical physics community to study cold atomic physics in microgravity, said David Aveline of JPL, CAL ground testbed lead.

“Instead of a state-of-the-art telescope looking outward into the cosmos, CAL will look inward, exploring physics at the atomic scale,” Aveline said.

JPL is developing the Cold Atom Laboratory sponsored by the International Space Station Program at NASA’s Johnson Space Center in Houston.

The Space Life and Physical Sciences Division of NASA’s Human Exploration and Operations Mission Directorate at NASA Headquarters in Washington manages the Fundamental Physics Program.

See the full article here.

Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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From Science Daily: “Physicists have chilled the world’s coolest molecule”

Science Daily

August 21, 2014
Source: Yale University, The original article was written by Jim Shelton.

It’s official. Yale physicists have chilled the world’s coolest molecules.

An optical cavity used to control the wavelength of some of the lasers used for the magneto-optical trap. Credit: Photo by Michael Helfenbein

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 Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

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.

See the full article here.

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From D.O.E. Pulse: “Jefferson Lab engineers help space chamber reach cold target at unprecedented efficiency”

January 21, 2013

“As the U.S. sweated through its warmest year on record outside, a testing chamber at NASA Johnson Space Center in Houston reached its coldest temperatures yet on the inside, cooled by one of the world’s most efficient cryogenic refrigeration systems.

Designed by members of the Cryogenics group at the Department of Energy’s Jefferson Lab, the system reached its target temperature of 20 Kelvin, about -424 degrees F, for the first time in May 2012 and again during commissioning tests in late August. It reached its target temperature in just over a day and maintains a steady temperature with less than a tenth of a degree in variation over a load temperature range of 16 to 330 Kelvin, all with no loss of helium and using half the liquid nitrogen than comparable systems. But what is even more remarkable is its ability to maintain design efficiency down to a third of its maximum load.

‘The range of load temperature and capacity while maintaining peak efficiency and temperature stability is unprecedented, said Venkatarao (Rao) Ganni, deputy Cryogenics Department head, and a key member of the system design team.”

See the full article here.

DOE Pulse highlights work being done at the Department of Energy’s national laboratories. DOE’s laboratories house world-class facilities where more than 30,000 scientists and engineers perform cutting-edge research spanning DOE’s science, energy, National security and environmental quality missions. DOE Pulse is distributed twice each month.

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From Fermilab Today: “Cryogenics at Fermilab: Cooler than a frozen Han Solo”

Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

“Fermilab’s cryogenics R&D may not be able to deep-freeze a brazen Han Solo, but it can cool cutting-edge particle accelerators down—way down—to the optimum operational temperatures.

‘No one realizes how important the cryogenic cooling system is until it stops working,’ said Jay Theilacker, the head of the Cryogenics Department. ‘Many of the proposed experiments at Fermilab need to be cooled down to within a couple degrees of absolute zero to operate.’

In 2010, the American Recovery and Reinvestment Act granted Fermilab $114.2 million to cultivate the infrastructure for projects like SRF technology development, NOvA and LBNE. The cryogenics department received $10 million to establish the cooling systems required to chill these projects.

‘Fermilab built this entire building with money from the American Recovery and Reinvestment Act,’ Theilacker said while giving a tour of the brand-new Cryomodule Testing Facility (CMTF).

“Eventually, R&D for a number of different experiments will move into this building, but before any of these experiments can operate, they will need the cryogenic infrastructure.’ ”

The model of the Cryomodule Testing Facility shows the SLAC refrigerator in orange. The silver cylinder in the foreground is the cryogenic distribution box, and the large silver cylinder on the right is the superfluid helium cryogenic plant. Image: Dave Richardson, AD

Major construction of Fermilab’s Cryomodule Test Facility was completed in January 2012. This facility will house the new cryogenic systems as well as R&D for a number of different experiments. Photo: Jerry Leibfritz

See the full article here.