Mechanical motion used to 'spin' atoms in a gas

December 08, 2006

For the first time, mechanical motion has been used to make atoms in a gas "spin," scientists at the National Institute of Standards and Technology (NIST) report. The technique eventually might be used in high-performance magnetic sensors, enable power-efficient chip-scale atomic devices such as clocks, or serve as components for manipulating bits of information in quantum computers.

As described in the Dec. 1 issue of Physical Review Letters,* the NIST team used a vibrating microscale cantilever, a tiny plank anchored at one end like a diving board, to drive magnetic oscillations in rubidium atoms. The scientists attached a tiny magnetic particle--about 10 by 50 by 100 micrometers in size--to the cantilever tip and applied electrical signals at the cantilever's "resonant" frequency to make the tip of the cantilever, and hence the magnetic particle, vibrate up and down. The vibrating particle in turn generated an oscillating magnetic field that impinged on atoms confined inside a 1-square-millimeter container nearby.

The electrons in the atoms, acting like tiny bar magnets with north and south poles, responded by rotating about a static magnetic field applied to the experimental set-up, causing the atoms to rotate like spinning tops that are wobbling slightly. The scientists detected the rotation by monitoring patterns in the amount of infrared laser light absorbed by the spinning atoms as their orientation fluctuated with the magnetic gyrations. Atoms absorb polarized light depending on their orientation with respect to the light beam.

Micro-cantilevers are a focus of intensive research in part because they can be operated with low power, such as from a battery, and yet are sensitive enough to detect very slight changes in magnetic fields with high spatial resolution. The NIST team noted that coupling between cantilever motion and atomic spins is easy to detect, and that the atoms maintain consistent rotation patterns for a sufficiently long time, on the order of milliseconds, to be useful in precision applications.

For instance, by comparing the oscillation frequency of the cantilever to the natural rotation behavior of the atoms (determined by measuring the extent of the wobble), the local magnetic field can be determined with high precision. Or, arrays of magnetic cantilevers might be constructed, with each cantilever coupled vibrationally to the others and coupled magnetically to a unique collection of atoms. Such a device could be used to store or manipulate binary data in a quantum computer. In theory, the coupling process also could work backwards, so that atomic spins could be detected by monitoring the vibrational motion of the cantilevers.
-end-
The research was supported in part by the Defense Advanced Research Projects Agency.

* Y-J. Wang, M. Eardley, S. Knappe, J. Moreland, L. Hollberg, and J. Kitching. 2006. Magnetic resonance in an atomic vapor excited by a mechanical resonator. Physical Review Letters. Dec. 1.

National Institute of Standards and Technology (NIST)

Related Magnetic Fields Articles from Brightsurf:

Physicists circumvent centuries-old theory to cancel magnetic fields
A team of scientists including two physicists at the University of Sussex has found a way to circumvent a 178-year old theory which means they can effectively cancel magnetic fields at a distance.

Magnetic fields on the moon are the remnant of an ancient core dynamo
An international simulation study by scientists from the US, Australia, and Germany, shows that alternative explanatory models such as asteroid impacts do not generate sufficiently large magnetic fields.

Modelling extreme magnetic fields and temperature variation on distant stars
New research is helping to explain one of the big questions that has perplexed astrophysicists for the past 30 years - what causes the changing brightness of distant stars called magnetars.

Could megatesla magnetic fields be realized on Earth?
A team of researchers led by Osaka University discovered a novel mechanism called a ''microtube implosion,'' demonstrating the generation of megatesla-order magnetic fields, which is three orders of magnitude higher than those ever experimentally achieved.

Superconductors are super resilient to magnetic fields
A Professor at the University of Tsukuba provides a new theoretical mechanism that explains the ability of superconductive materials to bounce back from being exposed to a magnetic field.

A tiny instrument to measure the faintest magnetic fields
Physicists at the University of Basel have developed a minuscule instrument able to detect extremely faint magnetic fields.

Graphene sensors find subtleties in magnetic fields
Cornell researchers used an ultrathin graphene ''sandwich'' to create a tiny magnetic field sensor that can operate over a greater temperature range than previous sensors, while also detecting miniscule changes in magnetic fields that might otherwise get lost within a larger magnetic background.

Twisting magnetic fields for extreme plasma compression
A new spin on the magnetic compression of plasmas could improve materials science, nuclear fusion research, X-ray generation and laboratory astrophysics, research led by the University of Michigan suggests.

How magnetic fields and 3D printers will create the pills of tomorrow
Doctors could soon be administering an entire course of treatment for life-threatening conditions with a 3D printed capsule controlled by magnetic fields thanks to advances made by University of Sussex researchers.

Researchers develop ultra-sensitive device for detecting magnetic fields
The new magnetic sensor is inexpensive to make, works on minimal power and is 20 times more sensitive than many traditional sensors.

Read More: Magnetic Fields News and Magnetic Fields Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.