This image from the DZero detector shows
the typical outcome of a collision of a proton and an antiproton at Fermilab's
Tevatron collider. The curved red paths mark the trajectories of charged
particles recorded in the detector's central tracking chamber. The colored bars
indicate particle energies deposited in the detector. The blue disks correspond
to part of DZero's physical structure.
Physicists analyzed several years' worth
of results from the Tevatron collider and came up with the most accurate
measurement to date of the mass of the W boson, as well as narrowed down the
possible mass of the still undiscovered Higgs boson.
The DZero collaboration is supported by
the U.S. Department of Energy, the National Science Foundation (NSF) and
international funding agencies.
To learn more, read the NSF Discovery
story A Better Mass for the W Boson; Higgs Boson Given Less Space to Hide.
Berkeley Lab and UC Berkeley
Researchers Record First Direct Observations of Quantum Effects in an
Optomechanical System
A long-time staple of science fiction is
the tractor beam, a technology in which light is used to move massive objects –
recall the tractor beam in the movie Star Wars that captured the Millennium
Falcon and pulled it into the Death Star. While tractor beams of this sort
remain science fiction, beams of light today are being used to mechanically
manipulate atoms or tiny glass beads, with rapid progress being made to control
increasingly larger objects. Those who see major roles for optomechanical
systems in a host of future technologies will take heart in the latest results
from a first-of-its-kind experiment.
Scientists with the U.S. Department of
Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the
University of California (UC) Berkeley, using a unique optical trapping system
that provides ensembles of ultracold atoms, have recorded the first direct
observations of distinctly quantum optical effects – amplification and
squeezing – in an optomechanical system. Their findings point the way toward
low-power quantum optical devices and enhanced detection of gravitational waves
among other possibilities.
“We’ve shown for the first time that the
quantum fluctuations in a light field are responsible for driving the motions
of objects much larger than an electron and could in principle drive the motion
of really large objects,” says Daniel Brooks, a scientist with Berkeley Lab’s
Materials Sciences Division and UC Berkeley’s Physics Department.
Brooks, a member of Dan Stamper-Kurn’s
research group, is the corresponding author of a paper in the journal Nature
describing this research. The paper is titled “Nonclassical light generated by
quantum-noise-driven cavity optomechanics.” Co-authors were Thierry Botter,
Sydney Schreppler, Thomas Purdy, Nathan Brahms and Stamper-Kurn.
Light will build-up inside of an optical
cavity at specific resonant frequencies, similar to how a held-down guitar
string only vibrates to produce specific tones. Positioning a mechanical
resonator inside the cavity changes the resonance frequency for light passing
through, much as sliding one’s fingers up and down a guitar string changes its
vibrational tones. Meanwhile, as light passes through the optical cavity, it
acts like a tiny tractor beam, pushing and pulling on the mechanical resonator.
If an optical cavity is of ultrahigh
quality and the mechanical resonator element within is atomic-sized and chilled
to nearly absolute zero, the resulting cavity optomechanical system can be used
to detect even the slightest mechanical motion. Likewise, even the tiniest
fluctuations in the light/vacuum can cause the atoms to wiggle. Changes to the
light can provide control over that atomic motion. This not only opens the door
to fundamental studies of quantum mechanics that could tell us more about the
“classical” world we humans inhabit, but also to quantum information
processing, ultrasensitive force sensors, and other technologies that might
seem like science fiction today.
“There have been proposals to use
optomechanical devices as transducers, for example coupling motion to both
microwaves and optical frequency light, where one could convert photons from
one frequency range to the other,” Brooks says. “There have also been proposals
for slowing or storing light in the mechanical degrees of freedom, the equivalent
of electromagnetically induced transparency or EIT, where a photon is stored
within the internal degrees of freedom.”
Already cavity optomechanics has led to
applications such as the cooling of objects to their motional ground state, and
detections of force and motion on the attometer scale. However, in studying
interactions between light and mechanical motion, it has been a major challenge
to distinguish those effects that are distinctly quantum from those that are
classical – a distinction critical to the future exploitation of optomechanics.
Brooks, Stamper-Kurn and their
colleagues were able to meet the challenge with their microfabricated atom-chip
system which provides a magnetic trap for capturing a gas made up of thousands
of ultracold atoms. This ensemble of ultracold atoms is then transferred into
an optical cavity (Fabry-Pferot) where it is trapped in a one-dimensional
optical lattice formed by near-infrared (850 nanometer wavelength) light that
resonates with the cavity. A second beam of light is used for the pump/probe.
“Integrating trapped ensembles of
ultracold atoms and high-finesse cavities with an atom chip allowed us to study
and control the classical and quantum interactions between photons and the
internal/external degrees of freedom of the atom ensemble,” Brooks says. “In
contrast to typical solid-state mechanical systems, our optically levitated
ensemble of ultracold atoms is isolated from its environment, causing its
motion to be driven predominantly by quantum radiation-pressure fluctuations.”
The Berkeley research team first applied
classical light modulation to a low-powered pump/probe beam (36 picoWatts)
entering their optical cavity to demonstrate that their system behaves as a
high-gain parametric optomechanical amplifier. They then extinguished the classical
drive and mapped the response to the fluctuations of the vacuum. This enabled
them to observe light being squeezed by its interaction with the vibrating
ensemble and the atomic motion driven by the light’s quantum fluctuations.
Amplification and this squeezing interaction, which is called “ponderomotive
force,” have been long-sought goals of optomechanics research.
“Parametric amplification typically
requires a lot of power in the optical pump but the small mass of our ensemble
required very few photons to turn the interactions on/off,” Brooks says. “The
ponderomotive squeezing we saw, while narrow in frequency, was a natural
consequence of having radiation-pressure shot noise dominate in our system.”
Since squeezing light improves the
sensitivity of gravitational wave detectors, the ponderomotive squeezing
effects observed by Brooks, Stamper-Kern and their colleagues could play a role
in future detectors. The idea behind gravitational wave detection is that a
ripple in the local curvature of spacetime caused by a passing gravitational
wave will modify the resonant frequency of an optical cavity which, in turn,
will alter the cavity’s optical signal.
“Currently, squeezing light over a wide
range of frequencies is desirable as scientists search for the first detection
of a gravitational wave,” Brooks explains. “Ponderomotive squeezing, should be
valuable later when specific signals want to be studied in detail by improving
the signal-to-noise ratio in the specific frequency range of interest.”
The results of this study differ
significantly from standard linear model predictions. This suggests that a
nonlinear optomechanical theory is required to account for the Berkeley team’s
observations that optomechanical interactions generate non-classical light. Stamper-Kern’s
research group is now considering further experiments involving two ensembles
of ultracold atoms inside the optical cavity.
“The squeezing signal we observe is
quite small when we detect the suppression of quantum fluctuations outside the cavity,
yet the suppression of these fluctuations should be very large inside the
cavity,” Brooks says. “With a two ensemble configuration, one ensemble would be
responsible for the optomechanical interaction to squeeze the
radiation-pressure fluctuations and the second ensemble would be studied to
measure the squeezing inside the cavity.”
This research was funded by the Air
Force Office of Scientific Research and the National Science Foundation.
#
# #
Lawrence Berkeley National Laboratory
(Berkeley Lab) addresses the world’s most urgent scientific challenges by
advancing sustainable energy, protecting human health, creating new materials,
and revealing the origin and fate of the universe. Founded in 1931, Berkeley
Lab’s scientific expertise has been recognized with 13 Nobel prizes. The
University of California manages Berkeley Lab for the U.S. Department of
Energy’s Office of Science. For more, visit www.lbl.gov.
Led
by Berkeley Lab scientists, the Sloan Digital Sky Survey’s BOSS is bigger than
all other spectroscopic surveys combined for measuring the universe’s
large-scale structure
The Third Sloan Digital Sky Survey
(SDSS-III) has issued Data Release 9 (DR9), the first public release of data
from the Baryon Oscillation Spectroscopic Survey (BOSS). In this release BOSS,
the largest of SDSS-III’s four surveys, provides spectra for 535,995 newly
observed galaxies, 102,100 quasars, and 116,474 stars, plus new information
about objects in previous Sloan surveys (SDSS-I and II).
“This is just the first of three data
releases from BOSS,” says David Schlegel of the U.S. Department of Energy’s
Lawrence Berkeley National Laboratory (Berkeley Lab), an astrophysicist in the
Lab’s Physics Division and BOSS’s principal investigator. “By the time BOSS is
complete, we will have surveyed more of the sky, out to a distance twice as
deep, for a volume more than five times greater than SDSS has surveyed before –
a larger volume of the universe than all previous spectroscopic surveys
combined.”
Spectroscopy yields a wealth of
information about astronomical objects including their motion (called redshift
and written “z”), their composition, and sometimes also the density of the gas
and other material that lies between them and observers on Earth. The BOSS
spectra are now freely available at http://sdss3.org to a public that includes
amateur astronomers, astronomy professionals who are not members of the
SDSS-III collaboration, and high-school science teachers and their students.
The new release lists spectra for
galaxies with redshifts up to z = 0.8 (roughly 7 billion light years away) and
quasars with redshifts between z = 2.1 and 3.5 (from 10 to 11.5 billion light
years away). When BOSS is complete it will have measured 1.5 million galaxies
and at least 150,000 quasars, as well as many thousands of stars and other
“ancillary” objects for scientific projects other than BOSS’s main goal.
The
key to the history of the universe
BOSS is designed to measure baryon
acoustic oscillation (BAO), the large-scale clustering of matter in the
universe. BAO began as rippling fluctuations (“sound waves”) in the hot, dense
soup of matter and radiation that made up the early universe. As the universe
expanded it cooled. Finally atoms formed and radiation went its own way; the
density ripples left their marks as temperature variations in the cosmic
microwave background (CMB), where they can be detected today.
The CMB came into being 380,000 years
after the big bang, over 13.6 billion years ago, and continues to stretch
across the entire sky as the universe expands. Peaks in CMB temperature
variation occur about half a billion light years apart, at the same angle,
viewed from Earth, as peaks in the large-scale galactic structure that evolved
billions of years later. The regions of higher density in the CMB were in fact
the sources of galaxy formation; they correspond to regions where galaxies
cluster, along with intergalactic gas and concentrations of much more massive
underlying dark matter. The natural “standard ruler” marking peaks in
clustering can be applied not only across the sky but in all three dimensions,
backward in time to the CMB.
Distant quasars provide another way of
measuring BAO and the distribution of matter in the universe. Quasars are the
brightest objects in the distant universe, whose spectra bristle with
individually shifted absorption lines, a “Lyman-alpha forest” unique to each
that reveals the clumping of intergalactic gas and underlying dark matter
between the quasar and Earth.
Marks
on the cosmic ruler
Schlegel has called BAO “an
inconveniently sized ruler,” requiring “a huge volume of the universe just to
fit the ruler inside,” but it’s a precision tool for tracking the universe’s
expansion history, and for probing the nature of gravity and the mysterious
dark energy that’s causing expansion to accelerate.
To fill the huge volume, BOSS had to
find more and fainter objects in the sky at greater distances than SDSS had
attempted before. The camera system and spectrographs of the 2.5-meter Sloan
Foundation Telescope at the Apache Point Observatory in New Mexico had to be
completely rebuilt.
SDSS uses “plug plates” at the
telescope’s focal plane, aluminum disks with holes drilled to match the precise
position of previously imaged target objects. SDSS-I and II plug plates had
only 640 holes apiece, each covering three arcseconds; BOSS is using 2,000 plug
plates with 1,000 holes apiece, each covering a tight two arcseconds to reduce
light that’s not from the target.
Optical fibers are plugged into the
holes every day by hand, to guide the light from each target to a spectrograph.
While weather conditions vary night to night, observations on the best nights
use up to nine plug plates. For BOSS, the spectrographs were rebuilt with new
optics and new CCD detectors designed and fabricated at Berkeley Lab.
“Light from distant galaxies arrives at
Earth redshifted into the infrared,” says Natalie Roe, director of Berkeley Lab’s
Physics Division and BOSS’s instrument scientist, who led construction of the
spectrographs. “We optimized the BOSS spectrographs for mapping exactly these
galaxies.”
Working with Schlegel and Adam Bolton at
the University of Utah, Berkeley Lab’s Stephen Bailey is in charge of daily
“extraction pipeline” operations that convert raw data from the telescope into
useful spectra and quantities derived from them, ready for scientific analysis.
Data storage and the extraction pipeline run on the Riemann Linux cluster of
Berkeley Lab’s High-Performance Computing Services Group; the data is copied
from Riemann to the University of Utah, New York University, Johns Hopkins
University, and the National Energy Research Scientific Computing Center
(NERSC) at Berkeley Lab. The Lab also hosts the SDSS-III website,
http://sdss3.org, from which the data can be downloaded.
“Data releases are a proud tradition for
SDSS, and the first BOSS data greatly increase the SDSS store of information,”
Bailey says. “Members of the SDSS-III collaboration get first crack at it –
with barely enough time to write up their results – but three times as many
papers based on the data are published by scientists outside the
collaboration.”
Says Schlegel, “SDSS-III is already the
most used of all surveys from any telescope in the world, including the Keck
telescopes and the Hubble Space Telescope. With DR9, BOSS contributes a huge
information increase for all kinds of scientific investigations, from quasars to
how stars evolve to really odd objects like galaxy-scale strong gravitational
lenses. Meanwhile the BOSS BAO survey is over two-thirds finished, and ahead of
schedule – we’re well on our way to the best measure of BAO that will be made
for a long time. All the data BOSS collects will be available to anyone who can
use it.”
###
“The Ninth Data Release of the Sloan
Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon
Oscillation Spectroscopic Survey,” by Christopher Ahn et al, has been submitted
to the Astronomical Journal and may be found on the arXiv preprint server at
http://arxiv.org/abs/1207.7137.
“The Baryon Oscillation Spectroscopic
Survey of SDSS-III,” by Kyle Dawson, David Schlegel, and members of the BOSS
Collaboration, has been submitted to the Astronomical Journal and may be found
on the arXiv preprint server at http://arxiv.org/abs/1208.0022.
“Spectral Classification and Redshift
Measurement for the SDSS-III Baryon Oscillation Spectroscopic Survey,” by Adam
Bolton et al, has been submitted to the Astronomical Journal and may be found
on the arXiv preprint server at http://arxiv.org/abs/1207.7326
References to these and other papers
relating to Data Release 9 are in the SDSS-III Collaboration release at
http://www.sdss3.org/press/. Berkeley Lab researchers who are members of BOSS
and contributed to these papers include Stephen Bailey, William Carithers,
Andreu Font-Ribera, Jessica Kirkpatrick, Beth Reid, Natalie Roe, Nicholas Ross,
David Schlegel, and Martin White.
Lawrence Berkeley National Laboratory
addresses the world’s most urgent scientific challenges by advancing
sustainable energy, protecting human health, creating new materials, and
revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s
scientific expertise has been recognized with 13 Nobel prizes. The University of
California manages Berkeley Lab for the U.S. Department of Energy’s Office of
Science. For more, visit www.lbl.gov.
DOE’s Office of Science is the single
largest supporter of basic research in the physical sciences in the United
States, and is working to address some of the most pressing challenges of our
time. For more information, please visit the Office of Science website at
science.energy.gov/.
Funding for SDSS-III has been provided
by the Alfred P. Sloan Foundation, the Participating Institutions, the National
Science Foundation, and the U.S. Department of Energy Office of Science. The
SDSS-III web site is http://www.sdss3.org.
SDSS-III is managed by the Astrophysical
Research Consortium for the Participating Institutions of the SDSS-III
Collaboration including the University of Arizona, the Brazilian Participation
Group, Brookhaven National Laboratory, University of Cambridge, Carnegie Mellon
University, University of Florida, the French Participation Group, the German
Participation Group, Harvard University, the Instituto de Astrofisica de
Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins
University, Lawrence Berkeley National Laboratory, Max Planck Institute for
Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico
State University, New York University, Ohio State University, Pennsylvania
State University, University of Portsmouth, Princeton University, the Spanish
Participation Group, University of Tokyo, University of Utah, Vanderbilt
University, University of Virginia, University of Washington, and Yale
University.
With approval from the National Science
Board, the National Science Foundation (NSF) Director will advance the Large
Synoptic Survey Telescope (LSST) to the final design stage. This action permits
the NSF Director to include funds for LSST construction in a future budget
request. To be located in Chile, the LSST is a proposed 8-meter wide-field
survey telescope that will survey the entire sky approximately twice per week,
delivering a large and comprehensive data set that will transform astronomical
research.
The LSST was the first-ranked
ground-based large initiative in the 2010 National Academy of Sciences decadal
survey in astronomy and astrophysics. The project is a partnership among the
NSF, the Department of Energy (DOE) and a number of private contributors.
"LSST will provide an unprecedented
view of the sky while leading the emerging discipline of data-enabled
science," said NSF Director Subra Suresh. "The project will foster
international collaboration and offer unique methods for discovery in this new
age of Big Data."
Equipped with a 3-billion pixel digital
camera, the LSST will propel astronomy ever further into the era of
data-enabled science. By charting objects that change or move, and tracing
billions of remote galaxies, LSST will provide multiple probes of the
mysterious dark matter and dark energy, provide insight into short-lived
transient events such as astronomical explosions or collisions, and create a
more detailed map of the Milky Way and our own solar system.
"LSST will transform how scientists
detect and analyze astronomical events," said Edward Seidel, assistant
director for the NSF's Mathematical and Physical Sciences Directorate.
"The potential to deepen our understanding of the universe and its
constituents, from distant exploding stars to nearby asteroids, is
enormous."
NSF and DOE have recently signed a
formal Memorandum of Understanding delineating the scope of the agencies'
responsibilities throughout the lifetime of the project. NSF will be
responsible for development of the site and telescope, as well as the extensive
data management system. DOE, through a collaboration led by its SLAC National
Accelerator Laboratory, will be responsible for development and delivery of the
large-format camera. The Republic of Chile, through an agreement with
Universidad de Chile, will make available the observing site for the LSST
telescope.
The total construction cost of LSST is
estimated to be about $665M, approximately 70 percent from NSF, 24 percent from
DOE, and 6 percent from private donors to the project. The construction is
anticipated to last five years, followed by a two-year commissioning period
before the start of the survey.
NSF’s oldest program turns 60 this year,
and current Fellows are challenged to embrace the future with video creations
What do U.S. Secretary of Energy Steven
Chu, Google founder Sergey Brin and Freakonomics co-author Steven Levitt have
in common? All received funding for their graduate education through the
National Science Foundation's (NSF) Graduate Research Fellowship Program
(GRFP).
GRFP has a long history of supporting
outstanding graduate students in NSF-supported science, technology, engineering
and mathematics disciplines who are pursuing research-based master's and
doctoral degrees at accredited U.S. institutions.
Since 1952, NSF funded over 46,500
Graduate Research Fellowships out of more than half a million applicants. More
than 30 of them became Nobel laureates, and more than 440 became members of the
National Academy of Sciences. In addition, NSF Graduate Fellows have a higher
Ph.D. completion rate than non-Fellows.
The program is very competitive,
offering fellowships to 2,000 students annually in recent years from a pool of
about 12,000 applicants.
"This is NSF's signature
program," said Gisele Muller-Parker, program director for the GRFP.
"These students have demonstrated their potential to be high achieving
scientists and engineers. Their ideas and research contribute greatly to advancing
science and engineering research and innovation across all disciplines within
NSF. Many later credit the support they got through this program as a keystone
to their careers as scientists and engineers."
In honor of the program's 60th
anniversary, NSF invites Graduate Research Fellows to take part in a video
contest titled: "Creating the Future." The contest challenges Fellows
to create a short video, not to exceed 90 seconds, that communicates how their
NSF-funded research will help shape the future--for themselves, their field or
the world.
Submissions are due Sept. 14, and
winners--selected by a distinguished panel of judges, as well as by citizens at
large in a "People's Choice" category--will be announced in
mid-November. Contest winners will be awarded cash prizes. Details on contest
rules, eligibility and submission are provided on the GRFP Video Contest
webpage.
Also see a NSF special report on the
GRFP's 60th anniversary.
National Institute of Standards and
Technology, Gaithersburg, Md.
301-975-3776
mark.bello@nist.gov
WASHINGTON -- NASA and the National
Institutes of Standards and Technology (NIST) are sponsoring the second in a
series of regional public workshops to gather ideas and suggestions on the
design of the proposed National Network for Manufacturing Innovation (NNMI).
The workshop will be held July 9 at the Cuyahoga Community College in
Cleveland.
"Designing for Impact II: Workshop
on Building the NNMI" is a partnership between the interagency Advanced
Manufacturing National Program Office in Gaithersburg, Md., and local Cleveland
organizations that include NASA's Glenn Research Center, Cuyahoga Community
College and Case Western Reserve University. Confirmed workshop speakers are NASA
Deputy Administrator Lori Garver, NIST Director Patrick Gallagher and Ohio Sen.
Sherrod Brown. Invited speakers include congressional, state and local leaders.
Conceived to address strategic gaps in
U.S. manufacturing innovation, the NNMI is envisioned as a network of up to 15
regional hubs -- Institutes for Manufacturing Innovation -- that will connect
research discoveries and budding ideas for tomorrow's technologies and products
with current U.S. manufacturers and startup firms of tomorrow. The network is
proposed as a public and private collaboration in the President's FY 2013
budget.
These regional collaborations will bring
together industry, universities and community colleges, federal agencies and
states to accelerate innovation by investing in industrially relevant
manufacturing technologies with broad applications. They also will support
education and training of an advanced manufacturing work force.
Workshop participants will learn about
the principles and concepts behind the NNMI and participate in interactive
sessions designed to solicit ideas on how best to structure the network and the
institutes.
Facilitated interactive discussions will
focus on four areas key to the success of the institutes:
-- Technologies with broad impact
-- Institute structure and governance
-- Strategies for sustainable institute
operations
-- Education and work force development
This event builds on the first regional
workshop on designing and building the innovation network, held in Troy, N.Y.,
April 25. In addition, the Ohio workshop will explore manufacturing-related
interests and needs specific to the region.
The workshops are organized by the newly
created interagency Advanced Manufacturing National Program Office, which is
charged with coordinating federal resources and programs to enhance technology
transfer to U.S. manufacturers. The workshops are hosted by NIST. Core partner
agencies include NASA, the Department of Defense, Department of Energy and the
National Science Foundation.
The workshop will be held at Corporate
College East, which is part of Cuyahoga Community College. Advance sign-up is
required. Registration closes July 2. Attendees are charged a fee to cover food
and beverage expenses. Space is limited and event sign-up will be on a
first-come, first-served basis, with no more than four representatives from the
same organization. For more details on the workshop and to sign up for the
event, visit http://manufacturing.gov/amp/event_070912.html.
For more information about NASA and
agency programs, visit
This image from the DZero detector shows
the typical outcome of a collision of a proton and an antiproton at Fermilab's
Tevatron collider. The curved red paths mark the trajectories of charged
particles recorded in the detector's central tracking chamber. The colored bars
indicate particle energies deposited in the detector. The blue disks correspond
to part of DZero's physical structure.
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