Dec. 8, 2004
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A
Data ‘Repair Kit’ for Quantum Computers
 |
NIST
physicists Dietrich Leibfried and David Wineland in the
laboratory where they have developed a method for correcting
data handling errors for quantum computing.
©Geoffrey
Wheeler
For
a high-resolution version of this image, contact Gail
Porter. |
A practical
method for automatically correcting data-handling errors
in quantum computers has been developed and demonstrated
by physicists at the National Institute of Standards and
Technology (NIST).
Described
in the Dec. 2, 2004, issue of the journal Nature,
the NIST work is the first demonstration
of all the steps of
error correction for quantum computers, a futuristic, potentially
very powerful form of computing that uses the quantum properties
of atoms or other particles as 1s and 0s for processing data.
The method was implemented using ions (electrically charged
atoms) as quantum bits (qubits). Ions are arguably the leading
candidate for use as qubits in a quantum computer.
Conventional
computers use electronic switches that are either on or off
to represent 1s and 0s that then can be stored or manipulated
to make calculations. Quantum computing would use the quantum
states of matter as 1s and 0s—or even both at once. The
unusual features of the quantum world provide extra computational
power, offering the prospect of carrying out a massive number
of simultaneous calculations to solve problems that are impossible
to solve today. Specific applications could include code-breaking
of unprecedented power, faster database searching, fraud-proof
digital signatures and optimization of everything from communications
systems to airline schedules. But unless data-handling errors
are corrected, “noise” caused by environmental disturbances
could diminish any gains over today’s computers.
The new
NIST method helps to ensure the correctness of data during
computations by
creating what might be called
quantum
backup copies. “The basic concept is a familiar one:
If someone doesn’t understand what you say, you repeat
it several times, and eventually they’ll get it,” explains
physicist Dietrich Leibfried, who developed the approach
and helped to demonstrate its feasibility in NIST’s
Boulder, Colo., laboratories.
For further
information, see www.nist.gov/public_affairs/releases/quantum_repairkit.htm.
Software
Tool Finds 'Needles' in Data 'Haystacks'
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|
X-ray
data collected with a scanning electron microscope from
a nickel-aluminum alloy. Pure aluminum is represented
by blue, pure nickel by red and nickel-aluminum alloys
by colors in between. The green dot in the upper left
shows a contaminant particle of chromium identified
with the NIST software that occupied only one pixel
of the microscope's scanning area. The sample measures
about 160 micrometers across.
Click
here to download a high resolution version of this image.
Image
credit: D. Bright, D. Newbury/NIST
|
When
looking for a needle in a haystack, it's helpful to know
what a needle looks like. A new software tool developed
by researchers at the National Institute of Standards and
Technology (NIST) makes it possible to find chemical 'needles'
in data 'haystacks' without having to know anything about
the 'needle' in advance.
The NIST
software should be especially useful for analyzing ultrapure
metals—recently shown to have superior strength, corrosion-resistance
and other properties—and for monitoring nanoscale semiconductor
fabrication. Commercial X-ray detector manufacturers already
have included the method used in the software into their products.
Described
in the November issue of the Journal of Microscopy*,
the software works with scanning electron microscopes (SEMs)
and improves the analysis of X-ray data. SEMs raster a beam
of electrons across a sample and then detect X-rays emitted
in response. X-rays of specific energies (the equivalent of
colors for visible light) are emitted by specific elements,
making SEMs an excellent tool for mapping the chemical composition
of samples. The lateral and depth resolutions of SEM/X-ray
analysis range from 100 nanometers to 5 micrometers, depending
on specimen composition and SEM beam energy.
Newer
detectors—some developed with NIST funding—respond
so fast that data across the entire spectrum of X-ray energies
can be recorded for every pixel scanned. Typically, these
data are analyzed to show only the sample's major constituents.
The NIST software analyzes the data a step further by identifying
the X-ray energy with the highest intensity for each pixel
rather than for the sample as a whole. Using the software
with a nickel-aluminum sample, the NIST researchers identified
chromium and copper contaminant particles that occupied just
a single pixel and were not "visible" with the SEM's
usual data interpretation tools. [See graphic above.]
*D.S.
Bright and D.E. Newbury, "Maximum pixel spectrum: a new
tool for detecting and recovering rare, unanticipated features
from spectrum image data cubes," Journal of Microscopy,
Nov. 2004, pp. 186-193.
Microchip
Industry Strives to Perfect Its Timing
Time
is money, especially to the semiconductor industry. Electronics
manufacturers use extremely sophisticated equipment to churn
out the latest microchips, but they have a timing problem.
It's very difficult to get all the fabrication tools in a
manufacturing line to agree on the time. Components within
a single tool can disagree on the time by as much as two minutes,
because of a lack of synchronization.
According
to a
new report by the National Institute of Standards and
Technology (NIST) and International SEMATECH,* the timing
deficiencies will become important as device dimensions and
tolerances continue to shrink. In particular, timing becomes
critical as firms advance e-manufacturing concepts such as
real-time automation and intelligent control.
Tools
can be synchronized to about 100 millisecond (ms) accuracies
today, but with significant variations. The problems are myriad,
according to the report. For instance, subsystems made by
suppliers may lack the interfaces needed to synchronize their
clocks with host clocks made by original equipment manufacturers.
Quality control software that relies on time stamps to diagnose
processing errors may overload the computing resources of
fabrication systems, therefore degrading the time stamp accuracy.
There also is pressure to move forward: Methods are available
to reach 1 ms accuracy in the near future, but sub-millisecond
accuracies will be required eventually.
To help
achieve that level of precision, NIST is leveraging its timekeeping
expertise to support the industry's development of time synchronization
standards in collaboration with International SEMATECH's e-Manufacturing
initiatives. A next-generation time synchronization protocol
under development by the Institute of Electrical and Electronics
Engineers should improve the outlook, and NIST has developed
educational presentations and white papers to summarize the
key issues and potential solutions. In addition, NIST plans
to facilitate future standards development, possibly under
a new Time Synchronization Working Group, chartered by Semiconductor
Equipment Materials International.
*Ya-Shian
Li and Brad Van Eck. 2004. Semiconductor Factory and Equipment
Clock Synchronization for e-Manufacturing. International SEMATECH
Manufacturing Initiative, NISTIR 7184. A
PDF version is available here.
Media
Contact:
Laura
Ost, laura.ost@nist.gov,
(301) 975-4034
Identifying
Top Quality CD and DVD Media for Archiving
Will
your medical or bank records stored on CD or DVD still be retrievable
10 or 20 years from now? The answer depends on how well this
type of media are cared for and on specific manufacturing processes
used, according to a study* by researchers at the National Institute
of Standards and Technology (NIST).
Knowing that CDs and DVDs will work reliably for a certain
number of years is critical to government agencies, hospitals,
banks and other organizations that store massive amounts of
vital data on optical discs.
As part
of a long-term project* with the Library of Congress (LOC),
NIST researchers tested how well recordable optical disks made
with different manufacturing processes held up when exposed
to high temperatures, humidity and light levels. They found
that some disks performed better than others and that excessive
exposure to any of these conditions can accelerate the deterioration.
Crucially however, they found that some disks can be expected
to reliably store data for decades.
The question
is how can those high-quality media be identified for archival
applications. To address this issue, NIST, along with the DVD
Association (DVDA) and several government agencies, has formed
the Government Information Preservation Working Group. This
group is working with the optical disk industry to set requirements
for archival quality CD and DVD recordable media and to specify
to the industry the minimum number of years that recordable
CDs and DVDs need to last to meet their requirements. NIST researchers
also are developing a test that media manufacturers can use
to determine whether the CDs and DVDs meet the criteria for
archival use. Other federal agencies as well as industry organizations
are invited to join this effort and can contact the group at
gipwog@nist.gov.
*
A copy of the research paper (O. Slattery, R. Lu, J. Zheng,
F. Byers, and X. Tang “Stability Comparison of Recordable
Optical Discs—A Study of Error Rates in Harsh Conditions,”
NIST Journal of Research, Sept./Oct. 2004 ) and further
information on the working group are available at: http://www.itl.nist.gov/iad/894.05/gipwog/gipwog.html
.
Media
Contact:
Jan
Kosko, janice.kosko@nist.gov, (301) 975-2767
Quick
Links
Baldrige
2005 Criteria Now Available
The
2005 criteria used by businesses to apply for the
Malcolm Baldrige National Quality Award are now available;
editions for education and health care will be available
soon. The Baldrige Performance Excellence Criteria
are also used by thousands of organizations to assess
and improve their performance in a wide range of areas
including leadership, governance and ethics, employee
and customer relations, and results. Also available
is a worksheet that organizations can use in conjunction
with the criteria to do a simple self-analysis. The
worksheet can help identify an organization’s
strengths and opportunities for improvement and establish
goals and action plans. The criteria and the worksheet
are available at http://www.baldrige.nist.gov
or by calling (301) 975-2036.
Wanted:
Expert Reviewers for 2005 Baldrige Award
Each
year the Baldrige National Quality Program recruits
experts from business, education, health care and
other fields to serve as members of the board of
examiners for the Malcolm Baldrige National Quality
Award. Examiners evaluate applications for the
award and prepare feedback reports to applicants
citing strengths and opportunities for improvement.
The
board consists of more than 500 members, including
nine judges and about 60 senior examiners representing
many industries, companies and organizations, including
those from not-for-profit and public sectors. For
the 2005 board, NIST is particularly looking for applicants
who are physicians and those with experience in financial,
food manufacturing, utilities and not-for-profit sectors.
Service on the board provides an opportunity to enhance
a board member's knowledge, to develop a new network
of expert colleagues and to help improve U.S. competitiveness.
Applications for the board are available at http://baldrige.nist.gov/Examiner_Application.htm
or by calling (301) 975-2036.
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