May
18, 2005
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Quantum
Computing Results May Help in Code Breaking
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| This
colorized image shows the fluorescence from three trapped
beryllium ions illuminated with an ultraviolet laser beam.
Black and blue areas indicate lower intensity; red and
white indicate higher intensity.
Credit:
NIST
Click
here for a high resolution version of this photo.
|
A
crucial
step in a procedure that could enable future quantum computers
to break today’s most commonly used encryption codes has
been demonstrated by physicists at the National Institute of
Standards and Technology (NIST).
As reported
in the May 13 issue of the journal Science,* the NIST team
showed that it is possible to identify repeating
patterns in quantum information stored in ions (charged atoms).
The NIST work used three ions as quantum bits (qubits) to
represent 1s or 0s—or, under the unusual rules of quantum physics,
both 1 and 0 at the same time. Scientists believe that much
larger arrays of such ions could process data in a powerful
quantum computer. Previous demonstrations of similar processes
were performed with qubits made of molecules in a liquid, a
system that cannot be expanded to large numbers of qubits.
“Our
demonstration is important, because it helps pave the way
toward building a large-scale quantum computer,” says
John Chiaverini, lead author of the paper. “Our approach
also requires fewer steps and is more efficient than those
demonstrated previously.”
The NIST
team used electromagnetically trapped beryllium ions as qubits
to demonstrate a quantum
version of the “Fourier
transform” process, a widely used method for finding
repeating patterns in data. The quantum version is the
crucial final step in Shor’s algorithm, a series
of steps for finding the “prime factors” of
large numbers—the
prime numbers that when multiplied together produce a
given number.
Developed
by Peter Shor of Bell Labs in 1994, the factoring
algorithm sparked burgeoning interest in quantum computing.
Modern cryptography techniques, which rely on the fact
that even the fastest supercomputers require very long
times to
factor large numbers, are used to encode everything
from military communications to bank transactions. But a
quantum
computer
using Shor’s algorithm could factor a number
several hundred digits long in a reasonably short time.
This
algorithm made code breaking the most important application
for quantum
computing.
For further
information, see www.nist.gov/public_affairs/releases/fourier.htm.
*J. Chiaverini,
J. Britton, D. Leibfried, E. Knill, M.D. Barrett, R.B. Blakestad,
W.M. Itano, J.D. Jost, C. Langer, R. Ozeri, T. Schaetz and D.J.
Wineland. 2005. Implementation of the semiclassical quantum
Fourier transform in a scalable system. Science. May
13, 2005.
New
Initiative Will Map U.S. Measurement Needs
An
initiative to “roadmap” the nation’s future
measurement needs was announced May 11 by the National Institute
of Standards and Technology (NIST). Advances in such measurement
capabilities are basic to technological innovation, U.S.
industrial competitiveness, safety and security, and quality
of life.
“The
nation’s measurement system is a vital element
of our innovation infrastructure,” NIST Acting Director
Hratch Semerjian said during testimony before the House
Subcommittee on Environment, Technology, and Standards. “The
goal of this very important initiative, which will be undertaken
in close cooperation with the private sector and other
agencies,
is to ensure that the nation’s highest-priority measurement
needs are identified and met. We need to be certain that
the U.S. measurement system is robust so that it can sustain
America’s economy and citizens at world-class levels
in the 21st century.”
Semerjian
was testifying on the use of standards as barriers to export
markets. Test
and measurement methods are critical
for businesses to demonstrate compliance with regulatory
requirements and standards, which are the specifications
that define the features, performance levels, compatibility
and other attributes of products. The Organization for
Economic Cooperation and Development has estimated that
standards
influence up to 80 percent of world trade.
The
comprehensive, NIST-facilitated initiative, "Roadmapping
America’s Measurement Needs for a Strong Innovation
Infrastructure," will result in a first-ever evaluation
of the breadth, depth and overall health of the U.S.
measurement system. The final report, expected in early
2007, will identify
priority measurement infrastructure needs across industry
and the economy, recommend steps to address them and
point out the consequences of inaction.
For
further information, see www.nist.gov/public_affairs/releases/usms_nist.htm.
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| The
new JILA ultraviolet "ruler" is made by exposing
xenon gas atoms to a special type of infrared laser
light called a femtosecond frequency "comb."
The laser light is bounced back and forth between highly
reflective mirrors to increase its intensity. The process
causes the highly excited xenon to emit ultraviolet
light pulses spaced identically to the original infrared
comb. The new comb improves the precision of measurements
at the shorter UV wavelengths, just as a faster shutter
speed improves the ability of a camera to "see"
shorter-lived events.
Credit:
JILA
Click
here for high resolution version of this photo with
text.
Click
here for high resolution version of this photo without
text.
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World's
First UV 'Ruler' Sizes Up Atomic World
The
world's most accurate "ruler" made with extreme ultraviolet
light has been built and demonstrated with ultrafast laser pulses
by scientists at JILA, a joint institute of the National Institute
of Standards and Technology (NIST) and the University of Colorado
at Boulder.
The new
device, which consistently generates pulses of light lasting
just femtoseconds (quadrillionths of a second, or millionths
of a billionth of a second) in the ultraviolet region of the
electromagnetic spectrum, will be described in the May 20 issue
of Physical Review Letters.*
The device
is expected to become an important tool for ultraprecise measurements
in many fields of science, including chemistry, physics and
astronomy. A ruler made with shorter wavelengths of light makes
it possible to “see” more precise differences than
ever before in the energy levels of light emissions that identify
specific atoms, in the timing of chemical reactions, or, if
additional applications are developed, in the dimensions of
certain nanometer-scale objects. The new device also can be
compared to a camera with ultrafast shutter speeds and consistent
shot-to-shot frame speed and stability, allowing scientists
to take real-time “pictures” of finer structures
and dynamics. By combining many such pictures at a high speed,
scientists can gain a more detailed understanding of many phenomena.
“This
ultraviolet light source has a spectacularly high resolution,”
says Jun Ye, a NIST Fellow who leads the JILA research group.
“On the technological side, the system we used to produce
this light is simple and low cost, without active amplifiers.”
The new
laser device generates a “frequency comb,” so-called
because the frequency spectrum—a graphical representation
of the pattern made by many successive laser pulses building
on each other—looks like the evenly spaced teeth of a
hair comb. (See graphic.) The new comb is a short-wavelength
version of the optical frequency combs that in recent years
have enabled demonstrations of optical atomic clocks, which
are expected to be as much as 100 times more accurate than today’s
microwave-based atomic clocks. A femtosecond comb, because of
its high speed (or repetition rate), has the finest teeth of
any optical ruler.
For further
information, see www.nist.gov/public_affairs/newsfromnist_uvruler.htm.
*R.J. Jones,
K.D. Moll, M.J. Thorpe, and J. Ye. 2005. Phase-coherent frequency
combs in the VUV via high-harmonic generation inside a femtosecond
enhancement cavity. Physical Review Letters. May 20.
Media
Contact:
Laura
Ost, laura.ost@nist.gov,
(301) 975-4034
NIST
Method Improves Timing in Oscilloscopes
A
new method for correcting common timing errors in high-speed
oscilloscopes has been developed by researchers at the
National Institute of Standards and Technology (NIST).
The method improves the accuracy and clarity of measurements
performed in the development and troubleshooting of components
for wireless and optical communications, military radar
and other technologies.
Oscilloscopes
display graphical representations of electrical and optical
signals as waves, showing how the signals change over
time. These instruments often have inaccurate internal
clocks that distort output patterns, and they also can
exhibit random timing errors called jitter. These errors
may lead, for example, to false detection of failure in
a communications module that is actually working, or to
increased electronic "noise" interference with
measurements of microwave signals from radar.
The
NIST method, based on an approach developed in laboratory
experiments and implemented in freely available software,
constructs an alternative time base. The software analyzes
an oscilloscope's measurements of both a signal of interest
and two reference waves that are offset from each other.
The reference waves are generated by an external device
and are synchronized in time with the signal being measured.
Measurements of the reference waves are compared with
a calculation of an ideal wave to produce an estimate
of total time errors due to distortion and jitter. These
errors then can be corrected automatically for each measurement
made by the oscilloscope.
The
NIST correction method can be applied to older standard
equipment, can correct time records of almost any length
and can be applied to electromagnetic signals of almost
any frequency. It also provides the user with an estimate
of the residual timing error after the correction process
has been completed. The Timebase Correction software package
is available free of charge at www.boulder.nist.gov/div815/HSM_Project/Software.htm.
Media
Contact:
Laura
Ost, laura.ost@nist.gov,
(301) 975-4034
Rock
On! Indiana Limestone: NIST's First and Latest SRM
It
may sound like sentimentality, but it’s coldly practical—the
National Institute of Standards and Technology (NIST)
has reissued one of its earliest Standard Reference Materials
(SRMs), a mineral sample first distributed in 1910. Issue
“d” of SRM 1 consists of a 70-gram sample
of argillaceous (“containing clay”) limestone
quarried in Putnam County, Ind. NIST certifies each sample
for concentrations of 12 major chemical constituents and
offers “informational” values for 32 other
constituents and properties.
Standard Reference Materials are among the most widely
distributed and used products from NIST. The agency prepares,
analyzes and distributes well over a thousand different
materials that are used throughout the world to check
the accuracy of instruments and test procedures.
They
range from industrial materials like SRM 1 or SRM 2172
(“S-7 Tool Steel”) to samples used in clinical
chemistry (SRM 1951b—Lipids in Frozen Human Serum,
SRM 2390—DNA Profiling Standard), environmental
monitoring (SRM 1649—Urban Dust, SRM 1641—Mercury
in Water), electronics (SRM 476—Linewidth Measurement,
SRM 2543—Silicon Resistivity) criminal forensics
(SRM 2379—Drugs of Abuse in Human Hair, SRM 2285—Arson
Test Mixture), and dozens of others. About 350 SRMs support
the auto industry, for example, from manufacture of sheet
metal, windshields, tires, and transmission gears to final
assembly and subsequent operation.
Prosaic
limestone is a critical natural resource. In addition
to being a building material, it is used in the manufacture
of lime for agricultural and chemical processes, cement
and concrete, and iron and steel. NIST researchers worked
with the U.S. Geological Survey and six commercial laboratories
in the mining, minerals, construction and analytical services
sectors in the United States and Canada to produce SRM
1d. Details about SRM 1 and hundreds of other NIST Standard
Reference Materials can be found at www.nist.gov/srm.
Media
Contact:
Michael Baum, michael.baum@nist.gov, (301) 975-2763
Quick
Links
NIST
Smoothness Web Site Adds 3-D Analysis Tools
A
tiny irregularity in a product’s expected
smooth surface can mean a multimillion dollar
loss for manufacturers of everything from high-performance
wind tunnels to precision optical devices. New
features in a National Institute of Standards
and Technology (NIST) Web site, however, should
make quality assurance in such industries a
bit less fretful.
The
addition of three-dimensional surface analysis
capacity to the feature menu of the free, interactive
NIST Web site should be especially useful to
the mechanical parts, semiconductor and optical
industries where 3-D surface smoothness is key
to high-efficiency performance. The NIST Web
site enables manufacturers to check the accuracy
of measurement software used to verify the smoothness
of product surfaces. Until this month, the Web
site, called “Surface Metrology Algorithm
Testing System (SMATS),” was limited to
two-dimensional surface analysis.
A new circular fit measurement feature on the
2-D page of the website also allows manufacturers
of bearings and other cylindrical or spherical
products to check for errors in software packages
of the instruments they use.
The
NIST virtual surface calibration Web site is
available at http://ats.nist.gov/VSC/jsp.
Media
Contact:
John
Blair, john.blair@nist.gov,
(301) 975-4261
NIST
Showcase to Feature Nanotech and Bioscience
On
Thursday, June 9, NIST will showcase its nanotechnology
and bioscience resources (research, facilities,
collaborative opportunities) to representatives
of area businesses, venture capital firms, and
other local and regional organizations. The
all-day, NIST-hosted event, “Advancing
the Frontiers of Bioscience and Nanotechnology,”
is sponsored by the Maryland Technology Development
Corp. and the Technology Council of Maryland,
along with nearly 20 partner organizations.
Featured
technologies range from microfluidics to nanomagnetics
to interoperability standards for health care
applications. For more information, see www.nist.gov/public_affairs/confpage/050609a.htm.
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