March
24, 2005
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Noisy
Pictures Tell a Story of 'Entangled' Atoms
 |
Similar
patterns of "noise" are evident in these
two images. The images are taken directly after molecules
have been split into entangled atom pairs. Each of
the pictures shows the absorption of laser light by
potassium atoms in one out of two different energy
states. High concentrations of atoms absorbing light
are circled in yellow, and areas with fewer atoms
are circled in green. The similar pattern in the two
images directly shows the correlation between atoms
in the different states.
Click
here to download a higher resolution version of this
image. |
Patterns
of noise—normally considered flaws—in images
of an ultracold cloud of potassium provide the first-ever
visual evidence of correlated ultracold atoms, a potentially
useful tool for many applications, according to physicists
at JILA, a joint institute of the National Institute of
Standards and Technology (NIST) and the University of Colorado
at Boulder.
Described
in the March 21 online issue of Physical Review Letters,*
the noise analysis method could, in principle, be used to
identify and test the limits of entanglement, a phenomenon
Einstein called “spooky action at a distance.”
With entangled atom pairs, for example, the properties of
one atom instantaneously affect the properties of its mate,
even when the two are physically separated by substantial
distances. Such tests of the basic rules of quantum physics
could be helpful, for example, in efforts to design quantum
computers that would use the properties of individual neutral
atoms as 1s and 0s for storing and processing data.
The
method demonstrated at JILA also could enable scientists
to “see,” for the first time, other types of
correlations between atoms in fermionic condensates, a new
quantum state first created by the same JILA research group
(see www.nist.gov/public_affairs/releases/fermi_condensate.htm),
in which thousands of pairs of atoms behave in unison. And
it could perhaps be applied in highly sensitive measurement
techniques using beams of entangled atoms.
“There
are a number of interesting quantum states that are not
obviously seen if you just take a picture,” says Deborah
Jin of NIST, leader of the research group that developed
the new method and also previously created fermionic condensates.
“A Fermi condensate, for example, would not show up
in an ordinary image. However, correlations between atoms
should actually show
up in the noise in these images.”
 |
Ultracold
molecules (center) are split into entangled pairs of
atoms flying apart in opposite directions. A laser beam
(left) is used to create shadow images of the cloud
(right). The pairs of entangled atoms can then be found
by carefully studying the noise pattern in these pictures.
(credit: Markus Greiner/JILA)
Click
here to download a higher resolution version of this
image. |
The
noise appears as speckles in images of a cloud of ultracold
potassium atoms made under very specific conditions. This
noise is not random, as would be expected ordinarily, but
rather appears in duplicate patterns suggesting, although
not proving, that pairs of atoms are entangled with each
other—even when separated by as much as 350 micrometers.
(For comparison, a human hair is about 70 micrometers wide.)
For
further information, see
www.nist.gov/public_affairs/releases/entangled_atoms.htm.
*M.
Greiner, C.A. Regal, J.T. Stewart, and D.S. Jin. 2005. Probing
Pair-Correlated Fermionic Atoms through Correlations in
the Atom Shot Noise. Physical Review Letters, posted
online March 21, 2005.
Billions
in Cost Estimated for Firefighter Injuries
Firefighters
face a high chance of injury or death whether on the scene
of a fire, on the way to a fire or even during training—with
an estimated 81,000 injuries and 100 deaths in 2002 alone.
The National Institute of Standards and Technology (NIST)
recently released a study* that estimates the cost in 2002
of addressing firefighter injuries and of efforts to prevent
them to be $2.8 billion to $7.8 billion per year.
The study,
conducted by the TriData Division of System Planning Corporation,
Arlington, Va., for NIST, considered workers' compensation
payments and other insured medical expenses, including long-term
care; lost productivity and administrative costs of insurance.
It also factored in labor costs of investigating injuries,
along with the hours required for data collection, report
writing and filing. Other costs related to preventing injuries
and reducing their severity included expenditures for insurance
coverage, safety training, physical fitness programs and protective
gear and equipment.
The range
between the $2.8 billion to $7.8 billion reflects different
cost estimation models—one with a narrow approach to
possible related firefighter injury costs, the others with
broader views of economic impacts. Fire departments can use
the information to plan their fire prevention and firefighting
strategies. NIST plans to use the study as an aid to determining
what new research might lead to a reduction in injury costs
and to enhanced fire safety.
The study
stressed the importance of programs that minimize emergency
calls, prevent accidental fires, and reduce the incidents
of arson. It also calls for early detection of fires using
smoke detectors as well as improved on scene command procedures
to locate firefighters and understand threats to them. The
study praises firefighter bravery as “legendary and
real,” but calls for new ways to instill safety awareness
in firefighters. It also says that training injuries can be
minimized by developing better virtual reality simulations
for use in training firefighters.
Other
suggested ways to prevent injury and to cut cost include:
robots for reconnaissance and firefighting; early (remote)
sensing of firefighter injuries/illnesses; computer modeling
of deployment scenarios; early detection of building collapse;
and emphasis on heightened firefighter health and fitness.
TriData
Division, System Planning Corporation,The Economic Consequences
of Firefighter Injuries and Their Prevention. Final Report,
NIST GCR 05-874, March 2005
Media
Contact:
John
Blair, john.blair@nist.gov,
(301) 975-4261
Where’s
Waldo’s DNA? New NIST SRM Joins Search
A
new reference standard from the National Institute of
Standards and Technology (NIST) may help genetics labs
develop improved methods of searching for a mutant needle
in a DNA haystack.
A
single DNA molecule carrying part of a person’s
genetic code is a chain of basic chemical units called
nucleotides. The number of nucleotides can range from
about 16,500 in mitochondrial DNA (mtDNA) to several million
in nuclear DNA. A key mutation in a DNA strand may involve
only a single nucleotide and yet cause serious health
effects.
Accurate analysis of mitochondrial DNA (mtDNA), either
for forensic identification or for studying genetic-based
diseases, often hinges on the ability to detect such mutations
that occur only infrequently, even in the same individual.
Unlike the cell's nuclear DNA, a person's mtDNA is often
heteroplasmic—a mix of a dominant DNA sequence with
fewer mutated sequences that differ from the dominant
version by one or more nucleotides. There are hundreds
or thousands of mitochondria in cells, and the exact percentage
of the minority mtDNA in the mix can vary dramatically
in an individual from tissue to tissue and even from cell
to cell. In general, it can be very difficult to identify
variants that make up less than 20 percent of the sample
unless you already know they are there.
Researchers
face a similar problem of detecting low-frequency variants
when analyzing pooled samples of nuclear DNA from a population
of individuals in the hope of identifying specific mutations
responsible for genetic diseases.
To
help the research community develop and test more sensitive
techniques for detecting low-frequency mutations in heteroplasmic
DNA, NIST researchers have developed a new Standard Reference
Material, SRM 2394, “Heteroplasmic Mitochondrial
DNA Mutation Detection Standard.” The new material
is a set of mixtures, at 10 different certified concentrations,
of two DNA fragments that differ from each other at only
one position.
Media
Contact:
Michael Baum, michael.baum@nist.gov,
(301) 975-2763
Quick
Links
HIV/AIDS
Structure Database is a Hit with Researchers
In
the few short months since it was announced last
summer
(www.nist.gov/public_affairs/techbeat/tb2004_0715.htm#aids)
the NIST HIV Structural Reference Database (HIVSDB)
has logged about 2 million hits, making it one of
the Institute’s most popular data services
that doesn’t give the time. An information
resource for the HIV research community, the HIVSDB
collects,
annotates, archives and distributes structural data
for proteins involved in making HIV, the virus that
causes AIDS, as well as molecules that inhibit the
virus. The database is useful in developing new
AIDS
inhibitors by facilitating the online comparison
of the existing hundreds of AIDS inhibitors on the
basis
of their ability to attack specific locations in
the active site of the AIDS enzyme (HIV protease).
The
database is particularly valuable because it includes
not only data from the widely used RCSB Protein
Data
Bank, but also previously unpublished data from industrial
and other laboratories. The web interface also provides
novel tools using a new method called Chem-BLAST
to interactively compare inhibitors and study their
interaction
with the AIDS enzyme.
The
NIST HIVSDB was developed in collaboration with the
National Cancer Institute. The database was expanded
recently to include two-dimensional structural data
for 500 potent HIV protease inhibitor compounds supplied
by the National Institute of Allergy and Infectious
Diseases (NIAID). The entry point to the HIV Structural
Data Base is at http://xpdb.nist.gov/hivsdb/hivsdb.html.
New
Facility Recognized in Lab Design Competition
The
National Institute of Standards and Technology (NIST)
and HDR Inc. will accept an award on March 29 for
"high honors" in R&D Magazine’s
2005 Lab of the Year competition for the Advanced
Measurement Laboratory, a new facility completed last
year on NIST's Gaithersburg, Md., campus. HDR provided
architecture and engineering services on the project.
The
$235 million facility, regarded as the most technologically
advanced research facility of its kind in the world,
was judged by a jury of representatives from the architectural,
scientific and laboratory equipment communities, as
well as R&D Magazine editors. Specific
criteria the judges considered included siting, planning,
traffic flow, aesthetics, working conditions, lab
design, opportunities for collaboration and idea exchange,
energy efficiency, cost to build and cost to operate.
The
AML is an essential part of NIST’s mission of
advancing U.S. technological competitiveness. The
new facility allows NIST to provide the sophisticated
measurements and standards needed by U.S. industry
and the scientific community for key 21st-century
technologies such as nanotechnology, semiconductors,
biotechnology, advanced materials, quantum computing
and advanced manufacturing. It provides NIST researchers
with simultaneous tight control of temperature, humidity,
acoustics and vibration, as well as excellent air
cleanliness and electrical power quality. The facility
was dedicated on June 21, 2004.
For
further information on the AML, see
www.nist.gov/public_affairs/releases/aml_dedication.htm.
Fire
Retardant Foam Consortium to Meet
Polyurethane
foam is everywhere—from building insulation, to upholstered
furniture, carpet padding to automotive and bedding products.
The cellular plastic products, however, are under increased
scrutiny for their flammability. At the same time, environmental
concerns have caused manufacturers to stop using some of
the more effective brominated flame retardants in the product.
To
help industry respond, the National Institute of Standards
and Technology (NIST) will host a meeting on April 20 at
its Gaithersburg campus to discuss establishing a cooperative
research consortium to develop information useful for the
preparation of fire-safe foams that are environmentally
safe and cost-effective. The industry-led consortium would
create a database on foam flammability, develop generic
measurement tools, and ultimately make recommendations for
foam flammability testing methods and candidates for fire
safe foams.
Manufacturers,
additive suppliers, fire safety and environmental representatives
are invited to participate in the meeting and consortium.
Those interested in attending the free organizing meeting
should contact Jeffery Gilman at (301) 975-6573, or jeffrey.gilman@nist.gov.
The proposed consortium Web site is www.bfrl.nist.gov/866/foam/.
How
Long Should Digital Storage Media
Last?
Knowing
that CDs and DVDs will last for
a certain number of years is critical
to many government agencies, as
well as to hospitals, banks and
other organizations that store massive
amounts of vital data on optical
disks. But, how long is long enough?
To
help the National Institute of Standards
and Technology (NIST) develop a
standard test to estimate the longevity
of recordable optical media, the
DVD Association (DVDA) and the Government
Information Preservation Working
Group (GIPWoG) are asking federal
agencies and other organizations
to answer a very brief survey concerning
the longevity of optical media.
The deadline for responding is May
31, 2005.
The
test being developed by NIST will
not measure actual longevity but
will determine the archival quality
of the media and whether it will
last at least a minimum number of
years. The NIST researchers recently
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 can be expected to store data
reliably for several tens of years.
(A Web site on the NIST/Library of Congress Optical Media Longevity Study can be found at
www.itl.nist.gov/iad/894.05/loc.)
This item was edited on Sept. 20, 2007, to correct for a change in the URL of the referenced Web site.
NIST,
Utah State Collaborate on Sensor Technology
An
agreement signed March 14 between the National Institute
of Standards and Technology (NIST) and Utah State University
(USU) creates a formal partnership for collaboration in
the development and calibration of optical sensors for defense,
homeland security, weather prediction and climate research.
The
signing ceremony was hosted by Utah Senator Bob Bennett
with Under Secretary of Commerce for Technology Phillip
Bond, NIST Acting Director Hratch Semerjian, USU President
Stan Albrecht, Utah Senator Orrin Hatch, staff from Utah
Rep. Rob Bishop’s office, and other NIST and USU representatives
in attendance.
“NIST
is signing this memorandum of understanding today because
we believe that, by working together, exchanging people,
and sharing resources, our institutions can spur greater
progress in innovation, research and education,” said
Bond.
NIST and Utah State have an extensive history of collaboration
in measurements and standards for optical instruments, with
an emphasis on space-based applications. The Memorandum
of Understanding (MOU) will enhance that partnership. The
two organizations will address areas of critical technical
importance for improving national security and calibrating
instruments used in assessing the extent and consequences
of climate change, a necessary prerequisite for developing
effective environmental policies. Other potential areas
of collaboration include biotechnology, nanotechnology,
and computational chemistry.
For
additional information, see www.nist.gov/public_affairs/releases/nist_usu_partner.htm.
(Return
to NIST News Page)
Editor:
Gail Porter
Date
created:3/22/05
Date updated:9/20/2007
Contact: inquiries@nist.gov
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