Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ultra-Cold Substance Shows Stripes -- Behavior Explained

11.06.2003


Physicists at Ohio State University may have explained some strange behavior of the ultra-cold material known as Bose-Einstein condensate (BEC).


Tin-Lun Ho



The new analysis shows that scientists are closer than ever to harnessing BEC to perform useful functions such as quantum computing, said Tin-Lun Ho, professor of physics at Ohio State and the project’s principal investigator.

Ho has pioneered theoretical studies of BEC, an entirely new form of matter that defies description as a solid, liquid, or gas. The condensate forms when atoms of a single chemical element such as rubidium are cooled to temperatures so low that they condense together. One glob of the material measures less than half the width of a human hair, and functions as a single atom, or “superatom,” that operates under the laws of quantum physics.


Ho’s work may help scientists understand how BEC could be used in quantum computing, making powerful computer chips so small that they could not be seen by the naked eye.

Scientists can spin a glob of BEC by suspending it in a magnetic field and nudging it with pulses of laser light, causing an array of whirlpool-like vortices to form in the material. And when they squeeze the material in a magnetic field, the vortices appear to melt together and form stripes.

But the melting is merely an illusion, according to Ho and postdoctoral researcher Erich Mueller.

In a study to be published on the Web in the journal Physical Review A, they report that the BEC only appears to form stripes because the lattice pattern changes -- the vortices remain separate the entire time.

"The equations were so simple we developed them with pencil and paper -- no computer was needed," Ho said. “That means we are truly beginning to understand the Bose-Einstein condensate, and that’s the first step to learning whether we can control its behavior."

The finding solves a mystery uncovered by one of the first creators of BEC, Eric Cornell of the University of Colorado at Boulder. In 1999, Cornell’s team and two other experimental groups were able to spin BEC so fast that they caused a lattice of evenly spaced vortices to form within the material.

In 2002, Ho suggested that scientists might be able to cause BEC to achieve a much-desired quantum state, called the Quantum Hall state, if they increased the density of the vortices by spinning the BEC even faster. Inspired by this suggestion, Cornell decided to increase the density by squeezing the BEC. He saw the material change periodically between an array of vortices and a set of stripes, as if the vortex lattice was melting and then returning to its coherent form again and again.

"We had to wonder, if the vortices just melt together, how could they return to an organized pattern? We realized something strange was happening," Ho said.

When he and Mueller derived analytical equations to model the behavior of the condensate when it’s squeezed, to their surprise, they found that the results perfectly matched what Cornell saw.

But the vortices did not actually melt together, they just re-arranged themselves from a perfect lattice into a different and entirely unique flow pattern, Ho said. The behavior suggests that the density of the BEC is sensitive to even very small changes in the vortex array.

The significance of the new calculations, according to Ho, is that they show experimental scientists such as Cornell are on the right track in achieving the Quantum Hall state, even though a higher density of vortices is still needed to reach this goal.

Ho feels his latest work bodes well for BEC’s future possibilities.

"Any control you have over the material will help with processing quantum information," he said. "I’m optimistic that a lot of progress will happen in this area soon, and the dream of quantum computation may one day be realized."

Other applications may be possible along the way. For instance, this revolutionary control of matter in the laboratory could lead to more precise time measurement. Satellite navigation, global positioning systems, and the alignment of astronomical telescopes all depend on precise time measurements.

"Quantum computing is a distant goal, but in the process of reaching that goal, there are all kinds of benefits," Ho said.

This work was supported by NASA and the National Science Foundation.


Contact: Tin-Lun Ho, (614) 292-2046; Ho.6@osu.edu
Written by Pam Frost Gorder, (614) 292-9475; Gorder.1@osu.edu

Pam Frost Gorder | Ohio State University
Further information:
http://www.osu.edu/researchnews/archive/bestripe.htm

More articles from Physics and Astronomy:

nachricht From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison

nachricht Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

New pop-up strategy inspired by cuts, not folds

27.02.2017 | Materials Sciences

Sandia uses confined nanoparticles to improve hydrogen storage materials performance

27.02.2017 | Interdisciplinary Research

Decoding the genome's cryptic language

27.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>