Buffer gas cooling could open up the field of ultracold physics

Sep 17, 2009 By Miranda Marquit feature

(PhysOrg.com) -- "Scientists have been making Bose-Einstein Condensates [BECs] for nearly 15 years," Charlie Doret tells PhysOrg.com. "Essentially all BEC research to date, however, begins with laser cooling. Unfortunately, laser cooling is impractical for some atoms, and it is especially difficult with molecules, limiting the scope of new research."

In order to create a more general method for producing ultracold atoms and molecules, Doret, a graduate student at Harvard University, worked with a team to develop a method of buffer-gas cooling that would work for many different atoms and even for many molecules. “Our process is more general than ,” he explains. Along with Colin Connolly and John Doyle at Harvard and Wolfgang Ketterle at MIT, Doret believes that their more widely applicable technique will enable creation of BECs with new atoms and molecules. Their work can be found in Physical Review Letters: “Buffer-Gas Cooled Bose-Einstein Condensate.”

To make BECs with ultracold atoms and molecules, an initial cooling and trapping stage is needed. The atoms or molecules in question are cooled to a point where they are moving slowly enough to be trapped. Once they are trapped they can be cooled further, leading to Bose-Einstein condensation. BECs are useful in a number of experiments, and have potential practical applications due to their similarities to laser light. “Unfortunately,” Doret points out, “laser cooling just doesn’t work well for some stuff.”

In laser cooling, photons are sent to bombard the atom in such a way that it eventually slows down, via a scattering process. Doret explains that this technique is similar to using golf balls to slow down a bowling ball. “It works eventually, but it takes a lot of photon scattering events to slow an atom, just as you would expect to use a great many golf balls to effectively slow a bowling ball.”

Instead of using lasers to slow down an atom, Doret and his peers opted for using a buffer gas. “We have a cold gas that we can bounce off of hot atoms. Collisions with this buffer gas cools the atoms, making them easier to magnetically trap, after which they can be further cooled until they Bose-condense."

For the current experiment, the Harvard and MIT team used cooled helium gas as a buffer to cool metastable helium atoms. “We have demonstrated the process from start to finish with atoms, but we haven’t done it with molecules. But the principle should be the same, and our next attempt will probably be to attempt to use buffer-gas cooling - with a few little tweaks - to create a BEC of the NH molecule.”

A general path to BEC with molecules would be a huge step forward for ultracold physics, Doret insists. “One big effect it could have is for the possibility of building a quantum computer. One way that has been suggested is to take polar molecules and trap them in an optical lattice, using the cold molecules as qubits. Due to the difficulty of cooling molecules, getting polar molecules into a lattice is a challenging but important step. Buffer-gas cooling could work, though.”

In the end, Doret believes that buffer-gas cooling could provide the means to experiment further with BECs and other subjects of interest. “Buffer-gas cooling allows us to use and not accessible in the past. There are new applications to pursue, and more tools that can be brought into play. This could open up the entire field of ultracold physics.”

More information: Doret, et. al. “Buffer-Gas Cooled ,” Physical Review Letters (2009). Available online: http://link.aps.org/doi/10.1103/PhysRevLett.103.103005.

Copyright 2009 PhysOrg.com.
All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.

Explore further: Finding faster-than-light particles by weighing them

add to favorites email to friend print save as pdf

Related Stories

Controlling most atoms now possible

Mar 06, 2008

Stopping and cooling most of the atoms of the periodic table is now possible using a pair of techniques developed by physicist Mark Raizen at The University of Texas at Austin.

New way found to cool atoms and molecules

Aug 09, 2005

Physicists at The University of Texas say they've found a new technique for cooling atoms and molecules, allowing more effective quantum physics studies.

Atom 'noise' may help design quantum computers

Mar 02, 2007

As if building a computer out of rubidium atoms and laser beams weren't difficult enough, scientists sometimes have to work as if blindfolded: The quirks of quantum physics can cause correlations between the ...

'Tornadoes' are transferred from light to sodium atoms

Nov 09, 2006

For the first time, tornado-like rotational motions have been transferred from light to atoms in a controlled way at the National Institute of Standards and Technology. The new quantum physics technique can ...

Recommended for you

Finding faster-than-light particles by weighing them

Dec 26, 2014

In a new paper accepted by the journal Astroparticle Physics, Robert Ehrlich, a recently retired physicist from George Mason University, claims that the neutrino is very likely a tachyon or faster-than-light par ...

Controlling core switching in Pac-man disks

Dec 24, 2014

Magnetic vortices in thin films can encode information in the perpendicular magnetization pointing up or down relative to the vortex core. These binary states could be useful for non-volatile data storage ...

Atoms queue up for quantum computer networks

Dec 24, 2014

In order to develop future quantum computer networks, it is necessary to hold a known number of atoms and read them without them disappearing. To do this, researchers from the Niels Bohr Institute have developed ...

New video supports radiation dosimetry audits

Dec 23, 2014

The National Physical Laboratory (NPL), working with the National Radiotherapy Trials Quality Assurance Group, has produced a video guide to support physicists participating in radiation dosimetry audits.

Acoustic tweezers manipulate cell-to-cell contact

Dec 22, 2014

Sound waves can precisely position groups of cells for study without the danger of changing or damaging the cells, according to a team of Penn State researchers who are using surface acoustic waves to manipulate ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

E_L_Earnhardt
3 / 5 (2) Sep 17, 2009
A system of "cooling" for living cells could slow mitosis and stop cancer "cold". (It's the high-speed electrons that need to be cooled!) Please give this some thought! Cancer is excess energy!
JukriS
Sep 18, 2009
This comment has been removed by a moderator.
JukriS
Sep 18, 2009
This comment has been removed by a moderator.
JukriS
Sep 18, 2009
This comment has been removed by a moderator.
JukriS
Sep 18, 2009
This comment has been removed by a moderator.
RETT
5 / 5 (1) Sep 27, 2009
Earnhardt,

While I am not sure of the use or practicality of your idea, I am absolutely certain that the temperatures involved in BEC's have nothing to do with anything biological, as all biological activity has long ceased at such temperatures.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.