Bouncing atoms may be the key to the future of gravimetry

Apr 27, 2009 By Miranda Marquit feature

(PhysOrg.com) -- When studying cold atoms, scientists often use magnetic or optical traps to keep the atoms in place. However, in some cases experimentalists want to study free atoms, avoiding the effects of a trap. "One way to study free atoms," Cass Sackett tells PhysOrg.com, "is by bouncing them off a surface... most of the time, the atoms are free." He says that scientists have been interested in bouncing atoms for a long time, but that before now only about five bounces have been achieved. "Using magnets and certain lasers, it is possible to bounce atoms. However, they are lost relatively quickly."

Sackett, a scientist at the University of Virginia in Charlottesville, and his colleagues, Hughes and Burke, have managed to construct a scheme in which they were able to get 100 bounces out of atoms. “We succeeded with finely tuned ,” Sackett explains. The Virginia team’s work can be seen in : “Suspension of Atoms Using Optical Pulses, and Application to Gravimetry.”

“There are a number of experiments done with falling atoms,” Sacket says. “We focus on the use of our bouncing scheme for measuring , though.” Gravity can be measured very accurately using falling atoms, but it requires large equipment. “If you want to probe these atoms for precision measurements, you have let them fall a long way. The apparatus starts to get bigger and becomes awkward to handle. What are you going to do? You start talking about machines that are 10 meters tall so that you can drop atoms a longer way.”

Instead of building large measuring devices, Sackett and his peers propose using a more compact system using bouncing atoms. “You get similar effects, with the number of bounces involved, so you don’t need something that allows the atoms to fall a long way,” he says. “We rely on the fact that we can control lasers so well to set up a situation that might be able to replace falling atoms in experiments.”

While the team at the University of Virginia focused mainly on gravimetry applications, Sackett believes that this breakthrough could also be applied in other fields. “It might be used to improve atomic clocks and test for fundamental values of certain constants - constants like Planck’s constant.”

Sackett also sees potential for experiments that so far need to be done in space. “Since you can suspend atoms in a way, it’s sort of similar to the conditions in space, where nothing falls. For instance, in gravity, you can only get atoms so cold before our cooling techniques stop working. I think with bouncing, we could get much colder, to well below one nano-Kelvin. And it would be a lot less expensive than sending an experiment into space on a rocket.”

He is careful to underscore the fact that there is still a lot of work ahead to make the experiment work with the kind of precision they are hoping for. “Nothing new has to be developed,” Sackett says, “but we are working with different approaches to fine tune the process. There’s still quite a bit of work, but it looks promising, and we’ve taken the first steps.”

More information: Hughes, Burke and Sackett, “Suspension of Using Optical Pulses, and Application to Gravimetry.” Physical Review Letters (2009). Available online: http://link.aps.org/doi/10.1103/PhysRevLett.102.150403 .

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: New microscope collects dynamic images of the molecules that animate life

add to favorites email to friend print save as pdf

Related Stories

A step closer to a practical atom laser

Jul 19, 2007

“When doing precise measurements of any kind, it is important to be able to count something, such as photons coming by at any given time,” Mattias Johnsson tells PhysOrg.com.

Optical Atomic Clock: A long look at the captured atoms

Feb 05, 2008

Optical clocks might become the atomic clocks of the future. Their "pendulum", i.e. the regular oscillation process which each clock needs, is an oscillation in the range of the visible light. As its frequency is higher than ...

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.

Portable Precision: A New Type of Atomic Clock

Dec 10, 2008

(PhysOrg.com) -- The most accurate atomic clocks in the world are based on the output of cesium atoms. These ultra-precise fountain clocks measure the frequency and time interval of seconds by using a fountain-like movement ...

Creating a nanoscale laser

Mar 13, 2007

“Nowadays, people and companies want to try to make smaller and smaller integrated circuits. In order to do this, low-power optical devices, like lasers, are needed,” Tom Savels tells PhysOrg.com. Savels ...

Can alkaline earth metals be used in quantum computing?

Nov 14, 2008

(PhysOrg.com) -- "There are a number of different proposals for quantum computing," Andrew Daley tells PhysOrg.com. "These include solid state or semiconductor as well as atomic and molecular systems. We are considering atomic ...

Recommended for you

Cooling with molecules

Oct 22, 2014

An international team of scientists have become the first ever researchers to successfully reach temperatures below minus 272.15 degrees Celsius – only just above absolute zero – using magnetic molecules. ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

sender
2.5 / 5 (2) Apr 27, 2009
superfluid environments sound ideal for such processes i suppose it's one of the first times scientists are actively creating gravimetric fields, wonder how many and how powerful the cascading lasers would have to be to create some unknowns of physics