Home > Press > Physicists localize 3-D matter waves for first time
 |
Photo by
L. Brian Stauffer
An illustration of Anderson localization. The green balloons represent disordered barriers that localize the sound of the trumpet at its source. |
Abstract:
University of Illinois physicists have experimentally demonstrated for the first time how three-dimensional conduction is affected by the defects that plague materials. Understanding these effects is important for many electronics applications.
Physicists localize 3-D matter waves for first time
Champaign, IL | Posted on October 7th, 2011
Led by physics professor Brian DeMarco, the researchers achieved complete localization of quantum matter waves in three dimensions, first theorized roughly half a century ago. The group published its findings in the Oct. 7 issue of the journal Science.
Defects in materials are inevitable, but their effects are poorly understood. Understanding how disorder in a material affects waves traveling through it has implications for many applications, including ultrasonic waves in medical imaging, lasers for imaging and sensing, and electron waves for electronics and superconductors.
"The physics behind disorder is fundamental to understanding the impact of unavoidable material imperfections on these kinds of applications," DeMarco said.
Scientists have long theorized, but never observed, that strong disorder causing interference on all sides can trap a matter wave in one place, a phenomenon known as Anderson localization.
According to DeMarco, this is analogous to a trumpeter playing in a concert hall filled with randomly placed barriers that reflect sound waves. Instead of traveling in all directions, the sound stays at its source, never propagating outward because of destructive interference.
"The result? Perfect silence everywhere in the concert hall. The trumpeter blows into his instrument, but the sound never leaves the trumpet," DeMarco said. "That's exactly the case in our experiment, although we use quantum matter waves instead of sound, and the barriers are created using a speckled green laser beam."
To simulate electrons moving in waves through a metal, DeMarco's group uses ultra-cold atoms moving as matter waves in a disordered laser beam. Using laser light as an analogy for a material allows the researchers to completely characterize and control the disorder - a feat impossible in solids, which has made understanding and testing theories of Anderson localization difficult.
The researchers demonstrated that the laser light could completely localize the atoms - the first direct observation of three-dimensional Anderson localization of matter.
"This means that we can study Anderson localization in a way that is relevant to materials," DeMarco said. "Now, theories of Anderson localization in 3-D can be compared to our ‘material' and tested for the first time."
The team also measured the energy a particle needs to escape localization, known as the mobility edge. Waves with energy higher than the mobility edge are free to propagate throughout the disorder, but waves with energy lower than the mobility edge are completely localized - even when there is a path through the barriers.
By tuning the power of the speckled green laser beam, the researchers measured the relationship between the mobility edge and disorder strength. They found that as disorder increased, so did the mobility edge, meaning that materials with high concentrations of defects induce more localization.
DeMarco hopes to use the quantum-matter analogues to better understand and manipulate materials.
Eventually, he plans to use his measurements of Anderson localization and the mobility edge along with future work exploring other parameters to engineer materials to better perform specific applications - in particular, high-temperature superconductors.
"Comparing measurements on a solid to theory are complicated by our lack of knowledge of the disorder in the solid and our inability to remove it," DeMarco said. "But, that's exactly what we can do with our experiment, and what makes it so powerful and exciting."
The Defense Advanced Research Projects Agency, the Office of Naval Research and the National Science Foundation supported this work.
####
For more information, please click here
Contacts:
Liz Ahlberg
Physical Sciences Editor
217-244-1073
Brian DeMarco
217-244-9848
Copyright © University of Illinois at Urbana-Champaign
If you have a comment, please
Contact us.
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Bookmark:
The paper, “Three-Dimensional Anderson Localization of Ultracold Matter,” is available online:
News and information
Aspen Aerogels Announces $22.5 Million Private Placement May 18th, 2013
NanoInk, Inc. Assets To Be Sold May 18th, 2013
Beautiful "flowers" self-assemble in a beaker: Elaborate nanostructures blossom from a chemical reaction perfected at Harvard May 17th, 2013
Scientists capture first direct proof of Hofstadter butterfly effect May 17th, 2013
Add boron for better batteries: Rice University theorists say graphene-boron mix shows promise for lithium-ion batteries May 17th, 2013
Physics
Scientists capture first direct proof of Hofstadter butterfly effect May 17th, 2013
RUB physicists let magnetic dipoles interact on the nanoscale for the first time: 'Of great technical interest for future hard disk drives' May 15th, 2013
Superconductivity
A new twist for quantum systems April 17th, 2013
Interdisciplinary team demonstrates superconducting qualities of topological insulators: Findings may prove useful in search for elusive Majorana quasiparticle April 10th, 2013
Material turns 'schizophrenic' on way to superconductivity - Strange state: Some electrons remain mobile while their neighbors are locked down April 4th, 2013
Electrons are not enough: Cuprate superconductors defy convention March 18th, 2013
Govt.-Legislation/Regulation/Funding/Policy
Beautiful "flowers" self-assemble in a beaker: Elaborate nanostructures blossom from a chemical reaction perfected at Harvard May 17th, 2013
Artificial Forest for Solar Water-Splitting: Berkeley Lab Researchers Report First Fully Integrated Artificial Photosynthesis Nanosystem May 17th, 2013
Moth-Inspired Nanostructures Take the Color Out of Thin Films May 17th, 2013
NIA Public Briefing: Nanotechnology and the Council of Europe May 17th, 2013
Chip Technology
UC Riverside scientists discovering new uses for tiny carbon nanotubes: Adding ionic liquid to nanotube films could build smaller gadgets, and create more cost effective 'Smart Windows' that darken in bright sun May 15th, 2013
Nanometrics Announces Upcoming Investor Events May 14th, 2013
HELIOS Program Develops Complete Supply Chain for Integrating Photonics with CMOS Circuit via IC Fabrication Processes May 14th, 2013
Silex Microsystems Joins ENIAC Project PROMINENT To Bring Flexible and Cost Effective Inkjet Technologies to the MEMS Manufacturing Process: Silex Will Develop New Solutions for Through-Silicon Via Manufacture and Hermetic Wafer Bonding May 13th, 2013
Discoveries
Beautiful "flowers" self-assemble in a beaker: Elaborate nanostructures blossom from a chemical reaction perfected at Harvard May 17th, 2013
Artificial Forest for Solar Water-Splitting: Berkeley Lab Researchers Report First Fully Integrated Artificial Photosynthesis Nanosystem May 17th, 2013
Moth-Inspired Nanostructures Take the Color Out of Thin Films May 17th, 2013
Scientists capture first direct proof of Hofstadter butterfly effect May 17th, 2013
Announcements
Aspen Aerogels Announces $22.5 Million Private Placement May 18th, 2013
NanoInk, Inc. Assets To Be Sold May 18th, 2013
NIA Public Briefing: Nanotechnology and the Council of Europe May 17th, 2013
Scientists capture first direct proof of Hofstadter butterfly effect May 17th, 2013
Military
Using clay to grow bone: Researchers use synthetic silicate to stimulate stem cells into bone cells May 15th, 2013
Flawed Diamonds Promise Sensory Perfection: Berkeley Lab researchers and their colleagues extend electron spin in diamond for incredibly tiny magnetic detectors May 10th, 2013
Researcher Construct Invisibility Cloak for Thermal Flow: Copper-Silicon Plate Deflects Heat / Optical Process Transferred to Thermodynamics / Basis for Future Heat Management in Microchips and Components May 8th, 2013
Improved material for ‘laser welding’ of tissue in intestinal surgery May 8th, 2013
Quantum nanoscience
Scientists capture first direct proof of Hofstadter butterfly effect May 17th, 2013
New principle may help explain why nature is quantum May 15th, 2013
Flawed Diamonds Promise Sensory Perfection: Berkeley Lab researchers and their colleagues extend electron spin in diamond for incredibly tiny magnetic detectors May 10th, 2013
New magnetic graphene may revolutionize electronics May 10th, 2013