Public Release: 

Physics tip sheet #24 - August 7, 2002

American Physical Society

1) Asteroids show their colors
Z. Ivezic, R. H. Lupton, M. Juric, S. Tabachnik, T. Quinn, J. E. Gunn, G. R. Knapp, C. M. Rockosi, J. Brinkmann
Astronomical Journal (to appear)

A survey of the colors of more than 10,000 asteroids shows that the four main families of asteroids represent four main color types. The distinct optical colors indicate that each family has a different origin but the similarities within a family suggest that each family comes from one source. Over 90% of asteroids are thought to belong to one of the four families.


2) 3-D data storage in glass
K. Kawamura, M. Hirano, T. Kamiya, H. Hosono
Applied Physics Letters (Print issue: August 5, 2002)

Storing data in three dimensions would dramatically increase the storage potential for many devices. However, most techniques have been limited by how deep data can be written inside a sample. A new technique manages to write structures inside silica glass to a depth of 5 millimeters using a single extremely short laser pulse. The technique may find initial uses not in data storage but in creating optical devices such as new types of lasers.

Journal article:

3) 3-D x-ray microscope
J. Miao, T. Ishikawa, B. Johnson, E. H. Anderson, B. Lai, K. O. Hodgson
Physical Review Letters (Print issue: August 19, 2002)

A relatively new x-ray imaging technique has made its first foray into the third dimension. Using a computer algorithm and high energy x-rays, researchers were able to visualize two nanometer-scale etched patterns stacked one on top of the other. Potential applications include imaging disordered materials and biological samples such as cells and viruses. Because the method doesn't require crystals it could potentially image single molecules, perhaps in conjunction with a free electron laser--a large facility that provides an x-ray laser beam.

Physical Review Focus:
Journal article:

4) Reducing large-scale turbulence
Y. Amarouchene, H. Kellay
Physical Review Letters (to appear)

Addition of soluble polymers can have dramatic and useful effects on the flows of liquids, such as reducing viscosity, drag or turbulence. A new study shows how addition of polyethyleneoxide in concentrations of just a few parts per million can reduce large-scale turbulence while leaving small-scale fluctuations. The uses of this property are not yet explored but it could potentially allow better mixing of fluids without the associated inefficiencies of large-scale turbulence, or other applications.

Journal article: Available on request

5) Carving plasma channels in air
H. Yang, J. Zhang, Y. Li, J. Zhang, Y. Li, Z. Chen, H. Teng, Z. Wei, Z. Sheng
Physical Review E (Print issue: July 2002)

Firing ultrashort low-energy laser pulses through air causes ribbons of plasma up to 5 meters long but only 120 micrometers wide. The plasma consists of a soup of component electrons and nuclei ripped out of the atoms usually present in air. The authors suggest that the plasma channel could be kept open by firing more laser beams along its length.

Journal article:

6) Close-up of atomic cave-dwellers
V. Petkov, S. J. L. Billinge, T. Vogt, A. S. Ichimura, and J. L. Dye
Physical Review Letters (Print issue: August 12, 2002)

Researchers have captured the most detailed pictures yet of particles crowded into an industrially useful nanoscale sponge. They extended an old method for analyzing x-ray diffraction data to a zeolite--a porous crystalline substance--filled with metal ions. The result confirms that this material is the first room-temperature stable electride, a class of compounds with curious electrical, magnetic, and optical properties that may eventually have applications as nanoscale devices.

Physical Review Focus:
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7) Arrays of trapped atoms may function as quantum computer
R. Dumke, M. Volk, T. Muther, F. B. J. Buchkremer, G. Birkl, W. Ertmer
Physical Review Letters (To appear)

One- and two-dimensional arrays of neutral atoms have been trapped with each atom 125 micrometers from its neighbors. The set of traps is formed by an array of microlenses and each trap can be probed with additional laser beams to run quantum algorithms. In the experiments described, over 80 individual atoms are contained in their own traps. If each atom serves as one quantum bit, the size of this system compares favorably with the fewer than ten bits so far created in other implementations.

Journal article: Available on request


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