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  • richardmitnick 12:32 pm on August 19, 2017 Permalink | Reply
    Tags: , , , Caltech, Cosmic Magnifying Lens Reveals Inner Jets of Black Holes, , Gravitational lensing system discovered by OVRO, Much more distant galaxy containing a jet-spewing supermassive black hole, OVRO-Caltech's Owens Valley Radio Observatory   

    From Caltech: “Cosmic Magnifying Lens Reveals Inner Jets of Black Holes” 

    Caltech Logo

    Caltech

    08/15/2017

    Whitney Clavin
    (626) 395-1856
    wclavin@caltech.edu

    1
    Illustration shows the likely configuration of a gravitational lensing system discovered by OVRO. The “milli-lens” is located in or near the intervening spiral galaxy. The lens is magnifying blobs of jet material within the active galaxy PKS1413+135, but the blobs are too small to be seen in the radio image (top left), taken by MOJAVE. Only when the blobs move far away from the yellow core do they expand and are visible as the pink blobs in the image.
    Credit: Anthony Readhead/Caltech/MOJAVE

    Caltech Owens Valley Radio Observatory, Owens Valley, California

    1
    Image of the 40-meter telescope of the Owens Valley Radio Observatory (OVRO), located near Bishop, California.
    Credit: Anthony Readhead/Caltech

    Astronomers using Caltech’s Owens Valley Radio Observatory (OVRO) have found evidence for a bizarre lensing system in space, in which a large assemblage of stars is magnifying a much more distant galaxy containing a jet-spewing supermassive black hole. The discovery provides the best view yet of blobs of hot gas that shoot out from supermassive black holes.

    “We have known about the existence of these clumps of material streaming along black hole jets, and that they move close to the speed of light, but not much is known about their internal structure or how they are launched,” says Harish Vedantham, a Caltech Millikan Postdoctoral Scholar. “With lensing systems like this one, we can see the clumps closer to the central engine of the black hole and in much more detail than before.” Vedantham is lead author of two new studies describing the results in the Aug. 15 issue of The Astrophysical Journal. The international project is led by Anthony Readhead, the Robinson Professor of Astronomy, Emeritus, and director of the OVRO.

    Many supermassive black holes at the centers of galaxies blast out jets of gas traveling near the speed of light. The gravity of black holes pulls material toward them, but some of that material ends up ejected away from the black hole in jets. The jets are active for one to 10 million years—every few years, they spit out additional clumps of hot material. With the new gravitational lensing system, these clumps can be seen at scales about 100 times smaller than before.

    “The clumps we’re seeing are very close to the central black hole and are tiny—only a few light-days across. We think these tiny components moving at close to the speed of light are being magnified by a gravitational lens in the foreground spiral galaxy,” says Readhead. “This provides exquisite resolution of a millionth of a second of arc, which is equivalent to viewing a grain of salt on the moon from Earth.”

    A critical element of this lensing system is the lens itself. The scientists think that this could be the first lens of intermediate mass—which means that it is bigger than previously observed “micro” lenses consisting of single stars and smaller than the well-studied massive lenses as big as galaxies. The lens described in the new paper, dubbed a “milli-lens,” is thought to be about 10,000 solar masses, and most likely consists of a cluster of stars. An advantage of a milli-sized lens is that it is small enough not to block the entire source, which allows the jet clumps to be magnified and viewed as they travel, one by one, behind the lens. What’s more, the researchers say the lens itself is of scientific interest because not much is known about objects of this intermediate-mass range.

    “This system could provide a superb cosmic laboratory for both the study of gravitational milli-lensing and the inner workings of the nuclear jet in an active galaxy,” says Readhead.

    The new findings are part of an OVRO program to obtain twice-weekly observations of 1,800 active supermassive black holes and their host galaxies, using OVRO’s 40-meter telescope, which detects radio emissions from celestial objects. The program has been running since 2008 in support of NASA’s Fermi mission, which observes the same galaxies in higher-energy gamma rays.

    In 2010, the OVRO researchers noticed something unusual happening with the galaxy in the study, an active galaxy called PKS 1413+ 135. Its radio emission had brightened, faded, and then brightened again in a very symmetrical fashion over the course of a year. The same type of event happened again in 2015. After a careful analysis that ruled out other scenarios, the researchers concluded that the overall brightening of the galaxy is most likely due to two successive high-speed clumps ejected by the galaxy’s black hole a few years apart. The clumps traveled along the jet and became magnified when they passed behind the milli-lens.

    “It has taken observations of a huge number of galaxies to find this one object with the symmetrical dips in brightness that point to the presence of a gravitational lens,” says coauthor Timothy Pearson, a senior research scientist at Caltech who helped discover in 1981 that the jet clumps travel at close to the speed of light. “We are now looking hard at all our other data to try to find similar objects that can give a magnified view of galactic nuclei.”

    The next step to confirm the PKS 1413+ 135 results is to observe the galaxy with a technique called very-long-baseline interferometry (VLBI), in which radio telescopes across the globe work together to image cosmic objects in detail. The researchers plan to use this technique beginning this fall to look at the galaxy and its supermassive black hole, which is expected to shoot out another clump of jet material in the next few years. With the VLBI technique, they should be able to see the clump smeared out into an arc across the sky via the light-bending effects of the milli-lens. Identifying an arc would confirm that indeed a milli-lens is magnifying the ultra-fast jet clumps spewing from a supermassive black hole.

    “We couldn’t do studies like these without a university observatory like the Owens Valley Radio Observatory, where we have the time to dedicate a large telescope exclusively to a single program,” said Readhead.

    Additional authors of The Astrophysical Journal studies are: Vikram Ravi of Caltech; Walter Max-Moerbeck (MS ’08, PhD ’13) and Anton Zensus of the Max Planck Institute for Radio Astronomy; Talvikki Hovatta of University of Turku and the Aalto University Metsähovi Radio Observatory; Anne Lähteenmäki and Merja Tornikoski of the Aalto University Metsähovi Radio Observatory; Mark Gurwell (MS ’92, PhD ’96) of the Smithsonian Astrophysical Observatory; Roger Blandford of Stanford University; Rodrigo Reeves of the University of Concepción; and Vasiliki Pavlidou of the University of Crete.

    The two studies, titled, Symmetric Achromatic Variability in Active Galaxies: A Powerful New Gravitational Lensing Probe? and The Peculiar Light Curve of J1415+1320: A Case Study in Extreme Scattering Events, are funded by NASA, the National Science Foundation, the Smithsonian Institution, the Academia Sinica, the Academy of Finland, and the Chilean Centro de Excelencia en Astrofísica y Tecnologías Afines (CATA).

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

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  • richardmitnick 5:28 pm on August 15, 2017 Permalink | Reply
    Tags: , Caltech, Earthquake friction slippage, The "seismological wind tunnel" at Caltech, The precise nature of dynamic friction remains one of the biggest unknowns in earthquake science   

    From Caltech: “How Friction Evolves During an Earthquake” 

    Caltech Logo

    Caltech

    08/15/2017

    Robert Perkins
    (626) 395-1862
    rperkins@caltech.edu

    1
    The “seismological wind tunnel” at Caltech. The white square block in the center is a plastic known as homalite that acts as an analogue for rock. It contains a miniature fault that is triggered via a nickel-chromium wire fuse to produce a tiny simulated earthquake.
    Credit: Courtesy of Vito Rubino

    By simulating earthquakes in a lab, engineers at Caltech have documented the evolution of friction during an earthquake—measuring what could once only be inferred, and shedding light on one of the biggest unknowns in earthquake modeling.

    Before an earthquake, static friction helps hold the two sides of a fault immobile and pressed against each other. During the passage of an earthquake rupture, that friction becomes dynamic as the two sides of the fault grind past one another. Dynamic friction evolves throughout an earthquake, affecting how much and how fast the ground will shake and thus, most importantly, the destructiveness of the earthquake.

    “Friction plays a key role in how ruptures unzip faults in the earth’s crust,” says Vito Rubino, research scientist at Caltech’s Division of Engineering and Applied Science (EAS). “Assumptions about dynamic friction affect a wide range of earthquake science predictions, including how fast ruptures will occur, the nature of ground shaking, and residual stress levels on faults. Yet the precise nature of dynamic friction remains one of the biggest unknowns in earthquake science.”

    Previously, it commonly had been believed that the evolution of dynamic friction was mainly governed by how far the fault slipped at each point as a rupture went by—that is, by the relative distance one side of a fault slides past the other during dynamic sliding. Analyzing earthquakes that were simulated in a lab, the team instead found that sliding history is important but the key long-term factor is actually the slip velocity—not just how far the fault slips, but how fast.

    Rubino is the lead author on a paper on the team’s findings that was published in Nature Communications on June 29. He collaborated with Caltech’s Ares Rosakis, the Theodore von Kármán Professor of Aeronautics and Mechanical Engineering at EAS, and Nadia Lapusta, professor of mechanical engineering and geophysics, who has joint appointments with EAS and the Caltech Division of Geological and Planetary Sciences.

    The team conducted the research at a Caltech facility, directed by Rosakis, that has been unofficially dubbed the “seismological wind tunnel.” At the facility, researchers use advanced high-speed optical diagnostics and other techniques to study how earthquake ruptures occur.

    “Our unique facility allows us to study dynamic friction laws by following individual, fast-moving shear ruptures and recording friction along their sliding faces in real time,” Rosakis says. “This allows us for the first time to study friction point-wise and without having to assume that sliding occurs uniformly, as is done in classical friction studies,” Rosakis adds.

    To simulate an earthquake in the lab, the researchers first cut in half a transparent block of a type of plastic known as homalite, which has similar mechanical properties to rock. They then put the two pieces together under pressure, simulating the static friction that builds up along a fault line. Next, they placed a small nickel-chromium wire fuse at the location where they wanted the epicenter of the quake to be. Triggering the fuse produced a local pressure release, which reduced friction at that location, and allowed a very fast rupture to propagate up the miniature fault.

    In this study, the team recorded these simulated earthquakes using a new diagnostic method that combines high-speed photography (at 2 million frames per second) with a technique called digital image correlation, in which individual frames are compared and contrasted with one another and changes between those images—indicating motion—are tracked with sub-pixel accuracy.

    “Some numerical models of earthquake rupture, including the ones developed in my group at Caltech, have used friction laws with slip-velocity dependence, based on a collection of rock mechanics experiments and theories. It is gratifying to see those formulations validated by the spontaneous mini-earthquake ruptures in our study, ” Lapusta says.

    In future work, the team plans to use its observations to improve the existing mathematical models about the nature of dynamic friction and to help create new ones that better represent the experimental observations; such new models would improve computer earthquake simulations.

    See the full article here .

    Please help promote STEM in your local schools.

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    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

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  • richardmitnick 11:55 am on August 7, 2017 Permalink | Reply
    Tags: , , , Caltech, Celebrating 40 Years of Voyager, ,   

    From Caltech: “Celebrating 40 Years of Voyager” 

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    Caltech

    Caltech screens “The Farthest—Voyager in Space” at Beckman Auditorium

    08/04/2017
    Robert Perkins
    (626) 395-1862
    rperkins@caltech.edu

    Voyager Humanity’s Farthest Journey
    In about 10 years, the twin Voyager spacecraft will go silent. Their plutonium-powered radioisotope thermoelectric generators, which are slowly losing power at a rate of four watts per year, will finally no longer be able to power the equipment needed to transmit messages back to Earth.

    A special space science presentation at NASA Headquarters highlights the contributions of the two Voyager spacecraft as they continue their multi-decade journey to the boundaries of our solar system and beyond.

    Having already given us a tour of the outer solar system, they will continue hurtling deeper into space—each carrying a copy of a golden record that contains a metaphorical message in a bottle from the people of Earth to any intelligent beings who may someday find it.

    But with no way to send messages, the probes’ last connection to the earth—and to the scientists and engineers who created them decades ago and have cared for them over the long years since—will be severed.

    One might expect that to be a source of sadness for Ed Stone, who has led the Voyager project for the past four decades. But when asked about it at a celebration of the 40th anniversary of the Voyager spacecraft held July 29 in Caltech’s Beckman Auditorium, Stone, Voyager project scientist for JPL and Caltech’s David Morrisroe Professor of Physics, expressed only gratitude.

    “I think the mission has been so overwhelmingly good that you can’t complain. After all, this is a 40-year mission of discovery already, and we have, maybe, up to 10 years more. And it would have been a great mission with half of that. I’m not going to be sad in that sense at all,” he said.

    At the event, Caltech hosted a screening of The Farthest—Voyager in Space, which tells the story of the Voyager mission and its journey to the outer planets and beyond. The documentary was produced by Tangled Bank Studios, the film production company founded by Howard Hughes Medical Institute as an extension of its science and education mission.

    Launched in 1977, the Voyager spacecraft took advantage of a rare alignment of the outer planets that allowed the spacecraft to slingshot from one world to the next, picking up speed at each planet. Voyager 1 conducted flybys of Jupiter and Saturn, while Voyager 2 flew by Jupiter, Saturn, Uranus, and Neptune.

    The program gathered data and images from the outer planets that revolutionized our understanding of the solar system—and each craft has continued to sail away from the earth bearing greetings, music, and images from humanity that have been preserved on two golden records. The Farthest explores the mission itself, from the highest highs—like the discovery of Jupiter’s rings and of active volcanism on other bodies in the solar system—to the lowest lows, like the moment that Voyager 2’s camera platform jammed while passing Saturn, temporarily crippling the spacecraft’s ability to make scientific observations.

    After the screening, Stone participated in a panel discussion about Voyager with Carolyn Porco (PhD ’83), of the Space Science Institute and Voyager 1 imaging specialist and imaging science team leader for the Cassini-Huygens mission; and Suzanne Dodd (BS ’84), Voyager project manager and JPL’s director for the Interplanetary Network Directorate. The discussion was moderated by science journalist Miles O’Brien.

    Porco, who joined the mission in the 1980s, described the thrill of being a part of the fast-paced action at JPL during planetary flybys. “I had this incredible sense of privilege that I was one of the people who was a part of this,” she said. “It was like someone dragged me by the hand and took me off on the most incredible journey and adventure that humanity had ever undertaken.”

    Porco described the mission as the “Apollo 11 of planetary exploration,” ascribing it with the same impact as the mission that first landed humans on the moon. Dodd echoed her sentiment, pointing out that Voyager paved the way for future probes to the outer solar system.

    “I always like to describe the Voyagers as the grandparents of planetary exploration. You’ve got the two Voyager spacecraft followed up by the children: Galileo at Jupiter and Cassini at Saturn, and pretty soon we’re going to have grandchildren with the Europa mission,” Dodd said. (Juno, which reached Jupiter’s orbit in 2016, would also qualify as a “grandchild” of Voyager, Stone noted.)

    Dodd’s mention of the Europa mission, which will send a probe to Jupiter’s icy moon, drew a question from an audience member about the schedule and plans for that future exploration.

    Her response: “You should ask the gentleman who’s on your right. …”

    The gentleman in question was Mike Watkins, director of JPL, who briefly stepped up to the microphone next to the audience member to praise the Voyager team and discuss the Europa mission.

    “I’m here in the audience, just like you guys are, marveling at these folks on stage and what happened when I was 10 years old,” Watkins said. “Those images from the Jupiter and Saturn flybys are part of why I went into what I did in grad school.” Watkins went on to describe plans for the Europa Clipper, which will be launched in the 2020s and conduct flybys of the moon, as well as the potential for a Europa lander at a future date. Interest in Europa is high because beneath the moon’s icy crust is a vast ocean of water—one of the prerequisites for life as we know it.

    Eventually, the conversation turned to the topic of the golden record—the “nonscientific” part of Voyager but the one that arguably has generated the most public interest. Regardless of whether intelligent life is out there or could ever even find the Voyager spacecraft someday, the important thing is that humanity was able to send Voyager at all, Stone said.

    “It’s not as though I think it’s ever going to be found,” Stone said. “It’s really a message to us that we were able to send such a message. When you think about it, that’s quite remarkable … that we were able to send a message into space into orbit around the Milky Way galaxy for billions of years.”

    The Farthest—Voyager in Space will premiere on Wednesday, August 23 at 9 p.m. ET on PBS.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

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  • richardmitnick 4:13 pm on June 15, 2017 Permalink | Reply
    Tags: Barry Barish, Caltech, , Kip S. Thorne, LIGO Team Wins Princess of Asturias Award, The late Caltech professor of physics Ronald W. P. Drever   

    From Caltech: “LIGO Team Wins Princess of Asturias Award” 

    Caltech Logo

    Caltech

    Whitney Clavin
    (626) 395-1856
    wclavin@caltech.edu

    1
    Barry Barish and Kip Thorne of Caltech

    2
    Rainer Weiss of MIT

    Caltech scientists Barry Barish, the Ronald and Maxine Linde Professor of Physics, Emeritus, and Kip S. Thorne (BS ’62), the Richard P. Feynman Professor of Theoretical Physics, Emeritus, have been awarded the 2017 Princess of Asturias Award for Technical and Scientific Research, along with Rainer Weiss of MIT and the entire LIGO Scientific Collaboration (LSC), a body of more than 1,000 international scientists who perform LIGO research. Past winners of the award in this category include Peter Higgs, François Englert and CERN (the European Organization for Nuclear Research), and Stephen Hawking. The prize consists a Joan Miró sculpture symbolizing the award and a cash prize of 50,000 euros (about 56,000 U.S. dollars).

    Thorne and Weiss, together with the late Caltech professor of physics Ronald W. P. Drever,

    4
    Ronald W. P. Drever

    are the founders of LIGO, the Laser Interferometer Gravitational-wave Observatory, which made history in 2016 when the LIGO team announced the first direct observation of gravitational waves—ripples in space and time predicted by Einstein 100 years earlier.

    Barish was the principal investigator for LIGO from 1994 to 2005, and director of the LIGO Laboratory from 1997 until 2006. He led LIGO through its final design stages and, under his leadership, the project was funded by the National Science Foundation and construction of the interferometers was completed. In 1997, he established the LSC, which continues to detect gravitational waves with LIGO.


    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project


    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib

    ESA/eLISA the future of gravitational wave research

    The Princess of Asturias Awards have been presented every year since 1981 by H. M. King Felipe of Spain. They come in eight different categories, from arts to international cooperation. Past recipients in all categories include Nelson Mandela, Arthur Miller, Susan Sontag, Doris Lessing, David Attenborough, Francis Ford Coppola, the Gates Foundation, and many more.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

    Caltech campus

     
  • richardmitnick 5:08 pm on June 12, 2017 Permalink | Reply
    Tags: , Caltech, , Researchers Find a Surprise Just Beneath the Surface in Carbon Dioxide Experiment   

    From LBNL: “Researchers Find a Surprise Just Beneath the Surface in Carbon Dioxide Experiment” 

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    Berkeley Lab

    Caltech

    June 12, 2017
    Glenn Roberts Jr.
    geroberts@lbl.gov
    (510) 486-5582

    Berkeley Lab, Caltech team combines theory, X-ray experiments to explain what’s at work in copper catalyst

    1
    Scientists are seeking ways to reduce environmentally harmful levels of carbon dioxide from vehicle emissions and other sources by improving chemical processes that convert carbon dioxide gas into ethanol (molecular structure shown here) for use in liquid fuels, for example. X-ray experiments at Berkeley Lab have helped to show what’s at work in the early stages of chemical reactions that convert carbon dioxide and water into ethanol. (Credit: Wikimedia Commons)

    While using X-rays to study the early stages of a chemical process that can reformulate carbon dioxide into more useful compounds, including liquid fuels, researchers were surprised when the experiment taught them something new about what drives this reaction.

    An X-ray technique at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), coupled with theoretical work by a team at the California Institute of Technology, Pasadena (Caltech), revealed how oxygen atoms embedded very near the surface of a copper sample had a more dramatic effect on the early stages of the reaction with carbon dioxide than earlier theories could account for.

    This information could prove useful in designing new types of materials to further enhance reactions and make them more efficient in converting carbon dioxide into other products. Large concentrations of carbon dioxide are harmful to health and the environment, so researchers have been pursuing ways to remove it from the atmosphere and safely store it or chemically convert it into more beneficial forms.

    1
    This false-color scanning electron microscopy image shows microscopic details on the surface of a copper foil that was used as a catalyst in a chemical reaction studied at Berkeley Lab’s Advanced Light Source [ALS]. The scale bar represents 50 microns, or millionths of a meter. (Credit: Berkeley Lab)

    LBNL/ALS

    To explain what was at work, the research team developed computer models, and revised existing theories to explain what they were witnessing in experiments. Their results were published online June 12 in the Proceedings of the National Academy of Sciences journal.

    Copper is a common catalyst – a material used to activate and speed up chemical reactions – and, although it is not efficient, it aids in the production of ethanol when exposed to carbon dioxide and water. In the studied reaction, the copper helps to chemically break down and reassemble carbon dioxide and water molecules into other molecules.

    “We found more than we thought we were going to find from this fundamental investigation,” said Ethan Crumlin, a scientist at Berkeley Lab’s Advanced Light Source (ALS) who co-led the study with Joint Center for Artificial Photosynthesis (JCAP) researchers Junko Yano, at Berkeley Lab, and William Goddard III, at Caltech.

    The ALS is an X-ray research facility known as a synchrotron that has dozens of experimental beam lines for exploring a wide range of microscopic properties in matter, and JCAP is focused on how to convert carbon dioxide, water, and sunlight into renewable fuels.

    “Having oxygen atoms just beneath the surface – a suboxide layer – is a critical aspect to this,” Crumlin said. The X-ray work brought new clarity in determining the right amount of this subsurface oxygen – and its role in interactions with carbon dioxide gas and water – to improve the reaction.

    “Understanding this suboxide layer, and the suboxide in contact with water, is integral in how water interacts with carbon dioxide” in this type of reaction, he added.

    Goddard and his colleagues at Caltech worked closely with Berkeley Lab researchers to develop and refine a quantum mechanics theory that fit the X-ray observations and explained the electronic structure of the molecules in the reaction.

    “This was a good looping, iterative process,” Crumlin said. “Just being curious and not settling for a simple answer paid off. It all started coming together as a cohesive story.”

    Goddard said, “This back-and forth between theory and experiment is an exciting aspect of modern research and an important part of the JCAP strategy to making fuels from carbon dioxide.” The Caltech team used computers to help understand how electrons and atoms rearrange themselves in the reaction.

    At Berkeley Lab’s ALS, researchers enlisted an X-ray technique known as APXPS (ambient pressure X-ray photoelectron spectroscopy as they exposed a thin foil sheet of a specially treated copper – known as Cu(111) – to carbon dioxide gas and added water at room temperature. In proceeding experiments they heated the sample slightly in oxygen to vary the concentration of embedded oxygen in the foil, and used X-rays to probe the early stages of how carbon dioxide and water synergistically react with different amounts of subsurface oxide at the surface of the copper.

    2
    In this atomic-scale illustration, trace amounts of oxygen (red) just beneath a copper (blue) surface, play a key role in driving a catalytic reaction in which carbon dioxide (black and red molecules) and water (red and white molecules) interact in the beginning stages of forming ethanol. Carbon dioxide molecules hover at the copper surface and then bend to accept hydrogen atoms from the water molecules. X-ray experiments at Berkeley Lab’s Advanced Light Source [ALS] helped researchers to understand the role of subsurface oxygen in this process. (Credit: Berkeley Lab)

    The X-ray studies, planned and performed by Marco Favaro, the lead author of the study, revealed how carbon dioxide molecules collide with the surface of the copper, then hover above it in a weakly bound state. Interactions with water molecules serve to bend the carbon dioxide molecules in a way that allows them to strip hydrogen atoms away from the water molecules. This process eventually forms ethanol, a type of liquid fuel.

    “The modest amount of subsurface oxygen helps to generate a mixture of metallic and charged copper that can facilitate the interaction with carbon dioxide and promote further reactions when in the presence of water,” Crumlin said.

    Copper has some shortcomings as a catalyst, Yano noted, and it is currently difficult to control the final product a given catalyst will generate.

    “If we know what the surface is doing, and what the model is for this chemical interaction, then there is a way to mimic this and improve it,” Yano said. The ongoing work may also help to predict the final output of a given catalyst in a reaction. “We know that copper works – what about different copper surfaces, copper alloys, or different types of metals and alloys?”

    [The question remains.]

    See the full article here .

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    A U.S. Department of Energy National Laboratory Operated by the University of California

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  • richardmitnick 4:07 pm on June 2, 2017 Permalink | Reply
    Tags: , , Caltech, Caltech Program Fosters Scientific Curiosity in Pasadena Unified Students, STEM IN ACTION AT CALTECH   

    From Caltech: “Caltech Program Fosters Scientific Curiosity in Pasadena Unified Students” 

    Caltech Logo

    Caltech

    06/01/2017
    Jon Nalick

    [STEM IN ACTION AT CALTECH]

    1
    First-year geophysics graduate student Celeste Labedz shows off the results of her comet-making demonstration at a May 18 Science Night event at Field Elementary School in Pasadena. Credit: Caltech

    Eye-catching demonstrations include levitating magnets, jets of flame, and steaming hunks of ice

    As a gaggle of wide-eyed elementary school students crowd in for a view, first-year geophysics graduate student Celeste Labedz plunges her gloved hands into a basin overflowing with carbon dioxide fog.

    With the children’s help moments earlier, she had combined ingredients including water and dry ice to demonstrate how comets form. Now she pulls out the finished product: a fist-sized chunk of ice flecked with dirt and trailing streamers of white mist.

    “Whoa!” one student cries. “Can we make another one?”

    Labedz’s visit to Field Elementary School in Pasadena on May 18 was part of the Science Night program that brings more than 30 Caltech volunteers—undergraduate, graduate, and postdoctoral scholars in physics, chemistry, biology, geology, astronomy, and engineering—to conduct science demonstrations for students at 11 schools across Pasadena and the San Gabriel Valley.

    Started in 2013, the program originally targeted three area schools, but grew rapidly as parents and teachers spread the word about the events, and more schools invited Caltech to partner with them, says Mitch Aiken, associate director for educational outreach in Caltech’s Center for Teaching, Learning, and Outreach.

    Aiken says the program helps expand Catech’s community involvement and provides benefits not only to local schools and their students, but also to the Institute and its students. “Through these events, our students and researchers are contributing to elevating overall science literacy while improving their own ability to explain complex topics to diverse audiences. That’s critical to their success as they prepare for careers in industry, research, and academia.”

    More than 200 parents and students attended the recent event, which also featured hands-on demonstrations of gyroscopes, super-cooled magnets, and gravity-wave detectors.

    “Many parents and students told me this was the best night of the year,” says Daniel Bagby, principal of Field Elementary. “The presenters were so passionate about their field—and it was contagious. Students wanted to show me what they were learning and the sheer joy they were experiencing was truly palpable.”

    Arian Jadbabaie, a first-year physics graduate student who says he volunteers for Science Night about twice a month, spent the evening at Field demonstrating how gyroscopes work. Having visitors stand atop a spinnable disk, he invited them to grip a bike tire by handles attached to the sides its center axis. With the wheel spinning, participants tilted it right and left and suddenly found themselves turning on the disk, frequently prompting surprised laughter.

    “My favorite part of the demonstrations is the look of amazement on the kids’ faces when they see how the world is so much stranger than what they’ve seen or imagined,” he says. “In those moments, I feel like I’m on the same level as they are, regardless of what additional technical knowledge I might have.”

    Taking a break from her comet-making demonstration, Labedz agrees: “When kids are excited about what they’re hearing, you can see it. Sometimes they can’t keep it to themselves and start bouncing around. It’s awesome to see that learning can have that kind of effect on a kid.”

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

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  • richardmitnick 12:21 pm on May 28, 2017 Permalink | Reply
    Tags: , , Caltech, W. M. Keck Foundation, W. M. Keck Jr. Center dedication   

    From Caltech: “Caltech’s Keck Center Rededicated to Honor Former Trustee W. M. Keck Jr.” 

    Caltech Logo

    Caltech

    May 12, 2017

    1
    Caltech President Thomas Rosenbaum (left) and members of the Keck family—(from left) T. J. Keck, Robert Day, Stephen Keck, and William Keck, III—rededicate the W. M. Keck Jr. Center.

    On May 12, 2017, President Thomas F. Rosenbaum hosted a luncheon and a ceremony renaming Caltech’s Keck Center to celebrate the legacy of W. M. “Bill” Keck Jr. and Caltech’s longstanding partnership with the W. M. Keck Foundation and Superior Oil Company, both founded by Keck Jr.’s father. Keck Jr. served on the Caltech Board of Trustees from 1961 until his death in 1982 and was a key member of the Investment Committee during most of his tenure on the board.

    “It’s been a great partnership over the years between the Keck family and Caltech,” said Robert Day, who has been the chairman and CEO of the W. M. Keck Foundation for over 20 years and is the nephew of Keck Jr. “I’m very proud of this day; it’s a wonderful thing.”

    “John Lennon rightly remarked that ‘a dream you dream alone is only a dream. A dream you dream together is reality.’ This rededication of the Keck Center makes very real the continuing partnership, this continuing realized dream between the Keck family, the Keck Foundation, and Caltech,” said Thomas F. Rosenbaum, Caltech’s Sonja and William Davidow Presidential Chair and Professor of Physics, at the event. “The man whose vision and support has allowed us to dream is Robert Day.”

    A campus landmark, the W. M. Keck Jr. Center combines the historic Tolman/Bacher House with a modern conference facility, providing a meeting space for the Caltech Board of Trustees and other distinguished campus guests as well as a home for the Keck Institute for Space Studies (KISS). Established in 2008 with initial funding from the W. M. Keck Foundation and support from NASA’s Jet Propulsion Laboratory (JPL), KISS was created to develop revolutionary concepts and technologies for future space missions by taking advantage of opportunities for increased collaboration between researchers on campus and at JPL. The institute has achieved exciting successes in the development of new planetary, Earth, and astrophysics space mission concepts and technology, including designing a manned mission to an asteroid in lunar orbit, planning for a mission to one of Mars’s moons, and playing a role in the Curiosity rover’s ability to determine the age of a rock on Mars for the first time.

    The rededication of the Keck Center, originally named for W. M. Keck Sr., honors Keck Jr.’s service to the Institute. Through his personal philanthropic investments, he provided support for Caltech graduate housing in the early 1960s. Built in 1961 on Holliston Avenue, the three-story Keck Graduate House contained 53 single rooms and housed students until the 1990s. Keck Jr. also made substantial gifts to the Keck Presidential Fund, which helped advance presidential priorities, including the recruitment and retention of preeminent scholars.

    The naming also recognizes Keck Jr.’s involvement as a director of the Keck Foundation in the organization’s longstanding commitment to Caltech. Established using proceeds from Superior Oil, the W. M. Keck Foundation has been a significant supporter of the Institute, with the organization’s first gift providing funds for the W. M. Keck Engineering Laboratories in 1959. Including that first gift, the foundation has supported facilities and programs ranging from the W. M. Keck Foundation Professorship in the Division of Geological and Planetary Sciences to the W. M. Keck Observatory on top of the Mauna Kea volcano on the island of Hawaii. The Keck Observatory has been at the cutting edge of scientific exploration for the past two decades in making major discoveries that have broadened our understanding of the universe. We now have an opportunity to expand our window on the universe using new instruments developed at Caltech and the Keck telescopes will continue to play key roles in the search for biosignatures beyond our solar system.

    The lunch program on May 12 brought together Keck family members, Caltech trustees, and Institute leadership. Also in attendance were faculty members involved in KISS, such as director Tom Prince, professor of physics at Caltech, and Edward Stone, David Morrisroe Professor of Physics and vice provost for special projects.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

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  • richardmitnick 3:29 pm on May 25, 2017 Permalink | Reply
    Tags: , , Caltech, , Fertilizer research, Nitrogen fixation   

    From Caltech: “Nitrogen Fixation Research Could Shed Light on Biological Mystery” 

    Caltech Logo

    Caltech

    05/25/2017

    Emily Velasco
    626-395-6487
    evelasco@caltech.edu

    1
    Fertilizer is applied to an agricultural field. Credit: Credit: SoilScience.info (CC BY 2.0)

    New Process Could Make Fertilizer Production More Sustainable

    Inspired by a natural process found in certain bacteria, a team of Caltech researchers is inching closer to a new method for producing fertilizer that could some day hold benefits for farmers—particularly in the developing world—while also shedding light on a biological mystery.

    Fertilizers are chemical sources of nutrients that are otherwise lacking in soil. Most commonly, fertilizers supply the element nitrogen, which is essential for all living things, as it is a fundamental building block of DNA, RNA, and proteins. Nitrogen gas is very abundant on Earth, making up 78 percent of our atmosphere. However, most organisms cannot use nitrogen in its gaseous form.

    To make nitrogen usable, it must be “fixed”—turned into a form that can enter the food chain as a nutrient. There are two primary ways that can happen, one natural and one synthetic.

    Nitrogen fixation occurs naturally due to the action of microbes that live in nodules on plant roots. These organisms convert nitrogen into ammonia through specialized enzymes called nitrogenases. The ammonia these nitrogen-fixing organisms create fertilizes plants that can then be consumed by animals, including humans. In a 2008 paper appearing in the journal Nature Geoscience, a team of researchers estimated that naturally fixed nitrogen provides food for roughly half of the people living on the planet.

    The other half of the world’s food supply is sustained through artificial nitrogen fixation and the primary method for doing this is the Haber-Bosch process, an industrial-scale reaction developed in Germany over 100 years ago. In the process, hydrogen and nitrogen gases are combined in large reaction vessels, under intense pressure and heat in the presence of a solid-state iron catalyst, to form ammonia.

    “The gases are pressurized up to many hundreds of atmospheres and heated up to several hundred degrees Celsius,” says Caltech’s Ben Matson, a graduate student in the lab of Jonas C. Peters, Bren Professor of Chemistry and director of the Resnick Sustainability Institute. ” With the iron catalyst used in the industrial process, these extreme conditions are required to produce ammonia at suitable rates.”

    In a recent paper appearing in ACS Central Science, Matson, Peters, and their colleagues describe a new way of fixing nitrogen that’s inspired by how microbes do it.

    Nitrogenases consist of seven iron atoms surrounded by a protein skeleton. The structure of one of these nitrogenase enzymes was first solved by Caltech’s Douglas Rees, the Roscoe Gilkey Dickinson Professor of Chemistry. The researchers in Peters’ lab have developed something similar to a bacterial nitrogenase, albeit much simpler—a molecular scaffolding that surrounds a single iron atom.

    The molecular scaffolding was first developed in 2013 and, although the initial design showed promise in fixing nitrogen, it was unstable and inefficient. The researchers have improved its efficiency and stability by tweaking the chemical bath in which the fixation reaction occurs, and by chilling it to approximately the temperature of dry ice (-78 degrees Celsius). Under these conditions, the reaction converts 72 percent of starting material into ammonia, a big improvement over the initial method, which only converted 40 percent of the starting material into ammonia and required more energy input to do so.

    Matson, Peters, and colleagues say their work holds the potential for two major benefits:

    • Ease of production: Because the technology being developed does not require high temperatures or pressures, there is no need for the large-scale industrial infrastructure required for the Haber-Bosch process. This means it might some day be possible to fix nitrogen in smaller facilities located closer to where crops are grown.

    “Our work could help to inspire new technologies for fertilizer production,” says Trevor del Castillo, a Caltech graduate student and co-author of the paper. “While this type of a technology is unlikely to displace the Haber-Bosch process in the foreseeable future, it could be highly impactful in places that that don’t have a very stable energy grid, but have access to abundant renewable energy, such as the developing world. There’s definitely room for new technology development here, some sort of ‘on demand’ solar-, hydroelectric-, or wind-powered process.”

    • Understanding natural nitrogen fixation: The nitrogenase enzyme is complicated and finicky, not working if the ambient conditions are not right, which makes it difficult to study. The new catalyst, on the other hand, is relatively simple. The team believes that their catalyst is performing fixation in a conceptually similar way as the enzyme, and that its relative simplicity will make it possible to study fixation reactions in the lab using modern spectroscopic techniques.

    “One fascinating thing is that we really don’t know, on a molecular level, how the nitrogenase enzyme in these bacteria actually turns nitrogen into ammonia. It’s a large unanswered question,” says graduate student Matthew Chalkley, also a co-author on the paper.

    Peters says their research into this catalyst has already given them a deeper understanding of what is happening during a nitrogen-fixing reaction.

    “An advantage of our synthetic iron nitrogenase system is that we can study it in great detail,” he says. “Indeed, in addition to significantly improving the efficiency of this new catalyst for nitrogen fixation, we have made great progress in understanding, at the atomic level, the critical bond-breaking and making-steps that lead to ammonia synthesis from nitrogen.”

    If processes of this type can be further refined and their efficiency increased, Peters adds, they may have applications outside of fertilizer production as well.

    “If this can be achieved, distributed solar-powered ammonia synthesis can become a reality. And not just as a fertilizer source, but also as an alternative, sustainable, and storable chemical fuel,” he says.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

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  • richardmitnick 2:42 pm on May 24, 2017 Permalink | Reply
    Tags: , Caltech, , , New imaging technique aims to ensure surgeons completely remove cancer,   

    From Wash U: “New imaging technique aims to ensure surgeons completely remove cancer” 

    Wash U Bloc

    Washington University in St.Louis

    Caltech Logo

    Caltech

    May 17, 2017
    Tamara Bhandari
    tbhandari@wustl.edu

    1
    A new imaging technique based on light and sound produces images doctors can use to distinguish cancerous breast tissue (below the dotted blue line) from normal tissue more quickly than is currently possible. Pathologists routinely inspect surgical specimens to make sure all cancerous tissue has been removed. The new technique (right) produces images as detailed and accurate as traditional methods (left), but in far less time. The researchers are working to make the technique fast enough to be used during a surgery, so patients don’t have to return for a second surgery. (Image: Terence T.W. Wong)

    Of the quarter-million women diagnosed with breast cancer every year in the United States, about 180,000 undergo surgery to remove the cancerous tissue while preserving as much healthy breast tissue as possible.

    However, there’s no accurate method to tell during surgery whether all of the cancerous tissue has been successfully removed. The gold-standard analysis takes a day or more, much too long for a surgeon to wait before wrapping up an operation. As a result, about a quarter of women who undergo lumpectomies receive word later that they will need a second surgery because a portion of the tumor was left behind.

    Now, researchers at Washington University School of Medicine in St. Louis and California Institute of Technology report that they have developed a technology to scan a tumor sample and produce images detailed and accurate enough to be used to check whether a tumor has been completely removed.

    Called photoacoustic imaging, the new technology takes less time than standard analysis techniques. But more work is needed before it is fast enough to be used during an operation.

    The research is published May 17 in Science Advances.

    “This is a proof of concept that we can use photoacoustic imaging on breast tissue and get images that look similar to traditional staining methods without any sort of tissue processing,” said Deborah Novack, MD, PhD, an associate professor of medicine, and of pathology and immunology, and a co-senior author on the study.

    The researchers are working on improvements that they expect will bring the time needed to scan a specimen down to 10 minutes, fast enough to be used during an operation. The current gold-standard method of analysis, which is based on preserving the tissue and then staining it to make the cells easier to see, hasn’t gotten any faster since it was first developed in the mid-20th century.

    For solid tumors in most parts of the body, doctors use a technique known as a frozen section to do a quick check of the excised lump during the surgery. They look for a thin rim of normal cells around the tumor. Malignant cells at the margins suggest the surgeon missed some of the tumor, increasing the chances that the disease will recur.

    But frozen sections don’t work well on fatty specimens like those from the breast, so the surgeon must finish a breast lumpectomy without knowing for sure how successful it was.

    “Right now, we don’t have a good method to assess margins during breast cancer surgeries,” said Rebecca Aft, MD, PhD, a professor of surgery and a co-senior author on the study. Aft, a breast cancer surgeon, treats patients at Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine.

    Currently, after surgery a specimen is sent to a pathologist, who slices it, stains it and inspects the margins for malignant cells under a microscope. Results are sent back to the surgeon within a few days.

    To speed up the process, the researchers took advantage of a phenomenon known as the photoacoustic effect. When a beam of light of the right wavelength hits a molecule, some of the energy is absorbed and then released as sound in the ultrasound range. These sound waves can be detected and used to create an image.

    “All molecules absorb light at some wavelength,” said co-senior author Lihong Wang, who conducted the work when he was a professor of biomedical engineering at Washington University’s School of Engineering & Applied Science. He is now at Caltech. “This is what makes photoacoustic imaging so powerful. Essentially, you can see any molecule, provided you have the ability to produce light of any wavelength. None of the other imaging technologies can do that. Ultrasound will not do that. X-rays will not do that. Light is the only tool that allows us to provide biochemical information.”

    The researchers tested their technique by scanning slices of tumors removed from three breast cancer patients. For comparison, they also stained each specimen according to standard procedures.

    The photoacoustic image matched the stained samples in all key features. The architecture of the tissue and subcellular detail such as the size of nuclei were clearly visible.

    “It’s the pattern of cells – their growth pattern, their size, their relationship to one another – that tells us if this is normal tissue or something malignant,” Novack said. “Overall, the photoacoustic images had a lot of the same features that we see with standard staining, which means we can use the same criteria to interpret the photoacoustic imaging. We don’t have to come up with new criteria.”

    Having established that photoacoustic techniques can produce usable images, the researchers are working on reducing the scanning time.

    “We expect to be able to speed up the process,” Wang said. “For this study, we had only a single channel for emitting light. If you have multiple channels, you can scan in parallel and that reduces the imaging time. Another way to speed it up is to fire the laser faster. Each laser pulse gives you one data point. Faster pulsing means faster data collection.”

    Aft, Novack and Wang are applying for a grant to build a photoacoustic imaging machine with multiple channels and fast lasers.

    “One day we think we’ll be able to take a specimen straight from the patient, plop it into the machine in the operating room and know in minutes whether we’ve gotten all the tumor out or not,” Aft said. “That’s the goal.”

    This work was supported by the National Institutes of Health, grant number DP1 EB016986 and R01 CA186567, and by Washington University’s Siteman Cancer Center’s 2014 Research Development Award.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”


    Caltech campus

    Wash U campus
    Wash U campus

    Washington University’s mission is to discover and disseminate knowledge, and protect the freedom of inquiry through research, teaching, and learning.

    Washington University creates an environment to encourage and support an ethos of wide-ranging exploration. Washington University’s faculty and staff strive to enhance the lives and livelihoods of students, the people of the greater St. Louis community, the country, and the world.

     
  • richardmitnick 8:04 am on April 23, 2017 Permalink | Reply
    Tags: , Caltech, New Quantum Liquid Crystals May Play Role in Future of Computers   

    From Caltech: “New Quantum Liquid Crystals May Play Role in Future of Computers” 

    Caltech Logo

    Caltech

    04/20/2017
    Whitney Clavin
    (626) 395-1856
    wclavin@caltech.edu

    1
    These images show light patterns generated by a rhenium-based crystal using a laser method called optical second-harmonic rotational anisotropy. At left, the pattern comes from the atomic lattice of the crystal. At right, the crystal has become a 3-D quantum liquid crystal, showing a drastic departure from the pattern due to the atomic lattice alone.
    Credit: Hsieh Lab/Caltech

    Physicists at the Institute for Quantum Information and Matter at Caltech have discovered the first three-dimensional quantum liquid crystal—a new state of matter that may have applications in ultrafast quantum computers of the future.

    “We have detected the existence of a fundamentally new state of matter that can be regarded as a quantum analog of a liquid crystal,” says Caltech assistant professor of physics David Hsieh, principal investigator on a new study describing the findings in the April 21 issue of Science. “There are numerous classes of such quantum liquid crystals that can, in principle, exist; therefore, our finding is likely the tip of an iceberg.”

    Liquid crystals fall somewhere in between a liquid and a solid: they are made up of molecules that flow around freely as if they were a liquid but are all oriented in the same direction, as in a solid. Liquid crystals can be found in nature, such as in biological cell membranes. Alternatively, they can be made artificially—such as those found in the liquid crystal displays commonly used in watches, smartphones, televisions, and other items that have display screens.

    In a “quantum” liquid crystal, electrons behave like the molecules in classical liquid crystals. That is, the electrons move around freely yet have a preferred direction of flow. The first-ever quantum liquid crystal was discovered in 1999 by Caltech’s Jim Eisenstein, the Frank J. Roshek Professor of Physics and Applied Physics. Eisenstein’s quantum liquid crystal was two-dimensional, meaning that it was confined to a single plane inside the host material—an artificially grown gallium-arsenide-based metal. Such 2-D quantum liquid crystals have since been found in several more materials including high-temperature superconductors. These are materials that conduct electricity with zero resistance at around –150 degrees Celsius, which is warmer than operating temperatures for traditional superconductors.

    John Harter, a postdoctoral scholar in the Hsieh lab and lead author of the new study, explains how 2-D quantum liquid crystals behave in strange ways. “Electrons living in this flatland collectively decide to flow preferentially along the x-axis rather than the y-axis even though there’s nothing to distinguish one direction from the other,” he says.

    Now Harter, Hsieh, and their colleagues at Oak Ridge National Laboratory and the University of Tennessee have discovered the first 3-D quantum liquid crystal. Compared to a 2-D quantum liquid crystal, the 3-D version is even more bizarre. Here, the electrons not only make a distinction between the x-, y-, and z-axes, but they also have different magnetic properties depending on whether they flow forward or backward on a given axis.

    “Running an electrical current through these materials transforms them from nonmagnets into magnets, which is highly unusual,” says Hsieh. “What’s more, in every direction that you can flow current, the magnetic strength and magnetic orientation changes. Physicists say that the electrons ‘break the symmetry’ of the lattice.”

    Harter hit upon the discovery serendipitously. He was originally interested in studying the atomic structure of a metal compound based on the element rhenium. In particular, he was trying to characterize the structure of the crystal’s atomic lattice using a technique called optical second-harmonic rotational anisotropy. In these experiments, laser light is fired at a material, and light with twice the frequency is reflected back out. The pattern of emitted light contains information about the symmetry of the crystal. The patterns measured from the rhenium-based metal were very strange—and could not be explained by the known atomic structure of the compound.

    “At first, we didn’t know what was going on,” Harter says. The researchers then learned about the concept of 3-D quantum liquid crystals, developed by Liang Fu, a physics professor at MIT. “It explained the patterns perfectly. Everything suddenly made sense,” Harter says.

    The researchers say that 3-D quantum liquid crystals could play a role in a field called spintronics, in which the direction that electrons spin may be exploited to create more efficient computer chips. The discovery could also help with some of the challenges of building a quantum computer, which seeks to take advantage of the quantum nature of particles to make even faster calculations, such as those needed to decrypt codes. One of the difficulties in building such a computer is that quantum properties are extremely fragile and can easily be destroyed through interactions with their surrounding environment. A technique called topological quantum computing—developed by Caltech’s Alexei Kitaev, the Ronald and Maxine Linde Professor of Theoretical Physics and Mathematics—can solve this problem with the help of a special kind of superconductor dubbed a topological superconductor.

    “In the same way that 2-D quantum liquid crystals have been proposed to be a precursor to high-temperature superconductors, 3-D quantum liquid crystals could be the precursors to the topological superconductors we’ve been looking for,” says Hsieh.

    “Rather than rely on serendipity to find topological superconductors, we may now have a route to rationally creating them using 3-D quantum liquid crystals” says Harter. “That is next on our agenda.”

    The Science study, titled A parity-breaking electronic nematic phase transition in the spin-orbit coupled metal Cd2Re2O7, was funded by the U.S. Department of Energy, the U.S. Army Research Office’s Defense University Research Instrumentation Program, the Alfred P. Sloan Foundation, the National Science Foundation, and the Gordon and Betty Moore Foundation.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”
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