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  • richardmitnick 9:26 am on April 18, 2018 Permalink | Reply
    Tags: 'Nuclear geyser' may be origin of life, Applied Research & Technology, , , , ,   

    From Tokyo Institute of Technology via COSMOS: “‘Nuclear geyser’ may be origin of life” 

    tokyo-tech-bloc

    Tokyo Institute of Technology

    COSMOS

    18 April 2018
    Richard A. Lovett

    1
    A natural geyser hearing by nuclear fission in a uranium deposit may have provided the ideal conditions for biomolecules to form. SOPA Images / Getty.

    Life may not have originated in the primordial soup of an ancient pond, according to scientists, but rather in a “nuclear geyser” powered by an ancient uranium deposit.

    Shigenori Maruyama of Tokyo Institute of Technology says the idea came from what chemists know about crucial compounds in our own bodies.

    Many of these compounds – including DNA and proteins – are polymers formed from chains of smaller building blocks.

    Each of these molecules serves a different purpose in the body, but something they all have in common, says Nicholas Hud, a chemist from Georgia Institute of Technology, Atlanta, is that a molecule of water is released when each new building block is added.

    “There is a theme here,” he said last week at a NASA-sponsored symposium on the early solar system and the origins of life. To a chemist, this suggests that these biopolymers must have originated under relatively dry conditions.

    Otherwise, Hud says, the presence of water would have forced the reactions to run backwards, breaking chains apart. But, there’s a problem: most scientists assume life started in water.

    The solution to this paradox, according to Hud, comes from realizing that water comes and goes. The major chemicals of life, and presumably life itself, may have formed in an environment that was alternately wet and dry. “It could be seasonal,” he says. “It could be tides. It could be aerosols that go up [into the air] and come back down.”

    Some prebiotic chemical reactions occur easily at moderate temperatures, but others, says Robert Pascal, a physical organic chemist from the University of Montpellier, France, require a more concentrated source of energy. This energy may have come from the sun, which in the early solar system was considerably more active than today. But another source is radiation.

    Which brings us back to nuclear geysers.

    Based on analyses similar to Hud’s and Pascal’s, Maruyama has identified nine requirements for the birthplace of life. One place where all can occur at once, Maruyama says, is in the plumbing of a nuclear geyser [Geoscience Frontiers].

    This would not only produce heat to power the geyser, but produce radiation strong enough to break the recalcitrant molecular bonds of water, nitrogen, and carbon dioxide, all of which must be cleaved in order to produce critical prebiotic compounds. Periodic eruptions of the geyser would also produce alternating wet and dry cycles, and water draining from the surface would bring back dissolved gases from the atmosphere. The rocks lining the geyser’s subterranean channels would provide a source of minerals such as potassium and calcium.

    “This is the place I recommend [for the origin of life],” Maruyama says.

    Once life originated, he says, it would have been spewed onto the surface and from there into the oceans. From there, it spread to every known habitable niche on the modern Earth.

    Extraterrestrial life (or at least life as we know it), he says, would need similar conditions in which to originate.

    That, he thinks, means the best place to look for it in our solar system is Mars. However habitable the subsurface oceans of outer moons such as Ganymede, Europa, and Titan may be for bacteria, they likely lack the conditions needed for the origin of life as we know it, he says.

    As for exoplanets? Similar conditions are also needed there, he says, including not only an energy source to power pre-biotic reactions, but a “triple junction” between rock, air, and water, where all the needed materials can come together simultaneously.

    See the full article here .

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    tokyo-tech-campus

    Tokyo Tech is the top national university for science and technology in Japan with a history spanning more than 130 years. Of the approximately 10,000 students at the Ookayama, Suzukakedai, and Tamachi Campuses, half are in their bachelor’s degree program while the other half are in master’s and doctoral degree programs. International students number 1,200. There are 1,200 faculty and 600 administrative and technical staff members.

    In the 21st century, the role of science and technology universities has become increasingly important. Tokyo Tech continues to develop global leaders in the fields of science and technology, and contributes to the betterment of society through its research, focusing on solutions to global issues. The Institute’s long-term goal is to become the world’s leading science and technology university.

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  • richardmitnick 8:30 am on April 18, 2018 Permalink | Reply
    Tags: A meteorite called Almahata Sitta, Applied Research & Technology, Diamonds from the heart of a lost planet, , , Ureilites   

    From EPFL via COSMOS: “Diamonds from the heart of a lost planet” 

    EPFL bloc

    École Polytechnique Fédérale de Lausanne

    COSMOS

    18 April 2018
    Richard A Lovett

    1
    Audrey Hepburn was a diamond-studded star, but scientists now think they’ve found evidence of a diamond studded planet. Wikipedia.

    Diamonds in a meteorite recovered from Sudan’s Nubian Desert have revealed traces of a lost planet, possibly as large as Mars, smashed to rubble early in the solar system’s history.

    Planetary scientists have long believed the solar system once teemed with such bodies, which, during its chaotic infancy, either merged into larger planets, fell into the sun, were flung into interstellar space, or were dashed to bits by catastrophic collisions. But this is the first direct evidence that any such lost world truly existed.

    The diamonds come from a meteorite called Almahata Sitta, which made headlines in 2008 when astronomers tracked a 4.1-metre asteroid into the Earth’s atmosphere and watched it explode in the skies above Sudan.

    3
    Almahata Sitta. https://www.meteorite-times.com/micro-visions/almahata-sitta/.

    Fragments collectively weighing about 10.5 kilograms were subsequently recovered and named for a railroad station between Khartoum and Wadi Halfa.

    Almahata Sitta proved to be part of a family of meteorites called ureilites [Space Science Reviews], of which several hundred are known.

    “They are interesting meteorites, with strange properties,” says Farhang Nabiei, a materials scientist at École Polytechnique Fédérale de Lausanne, Switzerland.

    Among other things, they include diamonds — enough to pose challenges to researchers.

    “Ureilites are hard to cut and grind for thin sections because of the diamonds,” says Melinda Hutson, curator of the Cascadia Meteorite Laboratory at Portland State University in the US.

    Nabiei and his team are the first to study these diamonds in detail.

    Diamonds can be produced in space by a number of processes, but the ones in Almahata Sitta are too large to have been formed by most of them, Nabiei says.

    They are not so large that thieves will be plundering them for gemstones. They are only 100 microns (0.1 millimetre) in size — barely large enough to be seen without a magnifying glass — and are badly cracked by subsequent events, such as impact shocks.

    But they are large enough, Nabiei says, that they must originally have formed deep inside a protoplanet, just as Earth’s diamonds formed far below its the surface.

    How deep can be determined by studying materials trapped within them.

    To jewellers, such materials, dubbed “inclusions”, would be considered defects, but to planetary scientists they are the true gems. Nabiei calls them “direct samples” of the places where the diamonds formed.

    Based on measurements of about 30 inclusions, he says, it appears that they could only have formed at pressures above 20 gigapascals (roughly 200,000 atmospheres).

    “So the body should have been large enough to have had 20 gigapascals pressure inside its mantle,” Nabiei explains.

    That means it must have been at least as large as Mercury, he says, which has a diameter of 4,900-kilometres, and possibly as big as Mars, with a 6,800 kilometre diameter. The difference depends on whether the Almahata Sitta diamonds formed all the way at the planet’s centre, or not quite as far down.

    Hutson, who was not part of the study team, notes that Nabiei’s lost planet isn’t the only protoplanet that may have been destroyed in collisions.

    Studies of a different class of meteorites, known as iron meteorites, she says, indicate that they may have been formed in protoplanets hundreds to thousands of kilometres across, “implying [other] large objects that have broken apart”. These, however, would not have been as large as the source of Nabiei’s diamonds.

    Fragments of such bodies, she says, could have helped produce the large impact basins we see today on the moon, Mercury, Mars, and Jupiter’s moon Callisto. They may also have crashed into the Earth or Venus, where we can no longer see their imprint. And, she adds, “A lot of material could have been ground down to small pieces in [subsequent] collisions [and] ejected from the solar system by a number of processes that remove sand and dust-sized particles.”

    The next step for Nabiei, whose work is published in the journal Nature Communications, is to look at more ureilites, seeking additional information about how their minerals formed — and from that, additional information about the lost world from which they originated.

    For example, he says, these meteorites have some characteristics of materials that formed in the inner solar system, but they also contain large amounts of carbon, similar to things that formed in its outer regions.

    “There are things we don’t understand,” he says, “and that’s where we learn.”

    See the full article here .

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    EPFL campus

    EPFL is Europe’s most cosmopolitan technical university. It receives students, professors and staff from over 120 nationalities. With both a Swiss and international calling, it is therefore guided by a constant wish to open up; its missions of teaching, research and partnership impact various circles: universities and engineering schools, developing and emerging countries, secondary schools and gymnasiums, industry and economy, political circles and the general public.

     
  • richardmitnick 7:57 am on April 18, 2018 Permalink | Reply
    Tags: Applied Research & Technology, , , , RV Investigator   

    From CSIROscope: “(100,000) nautical miles of science” 

    CSIRO bloc

    CSIROscope

    18 April 2018
    Matt Marrison

    0 NM
    Shipyard, Singapore – June 2014

    1
    Investigator in dry dock in Singapore. Image Mike Watson.

    ____________________________________________________
    For those converting at home…

    1 nautical mile (NM) = 1.85 kilometres (km) or 1.15 miles (mi)
    ____________________________________________________

    The ship is our research vessel Investigator. Newly built, it sits in dry dock at Sembawang Shipyard in Singapore. Freshly painted in blue, green and white, Investigator waits patiently for water to flood the dock to lift it from its supports and float free for the first time.

    It’s a big day.

    The ship is a game-changer for marine research in Australia. With capabilities far beyond those of previous Australian research vessels, Investigator will voyage far and do big science. It gives the nation a world-leading scientific edge to help answer big questions about the marine environment and resources, climate and food security.

    Installation complete, the ship log is switched on for the first time. The display flickers into life and shows 0 nautical miles (NM). Our journey begins.

    10,000 NM
    Derwent River, Tasmania – December 2014

    2
    Investigator arrives in its home port of Hobart, Tasmania.

    Science takes you places. Investigator has travelled from Singapore to Hobart, and is undergoing sea trials ahead of commissioning. The trials test the limit of the ship’s endurance, taking it past 60°S to the edge of the Antarctic sea ice.

    On return, and nearly three years after construction began, Investigator is commissioned at the CSIRO Marine Laboratories in Hobart on 12 December 2014.

    20,000 NM
    East Australian Current, Tasman Sea – June 2015

    3
    Discovering undersea volcanoes off the NSW coast.

    While on a voyage to study the East Australian Current, seafloor surveys pick up some unusual features off the coast of Sydney. They look like a row of egg cups. The egg cups are ancient marine volcanoes, never seen before, but now appearing in bright colour on monitors across the ship.

    Scientists watch the story unfold in the evening news as they continue their work on board. This ship runs on a 24/7 mix of high-octane science.

    30,000 NM
    Heard Island, Southern Ocean – January 2016

    4
    Investigator approaches the remote Heard Island. Image Pete Harmsen.

    Investigator has journeyed to a remote corner of our vast ocean estate to study volcanoes on the sea floor. While at Heard Island, steam rising from Big Ben signals to those on board that they have arrived in time to witness a rare eruption from one of Australia’s only active volcanoes.

    5
    Big Ben expresses himself, giving researchers a bang for their investigatory buck. Image: Pete Harmsen.

    40,000 NM
    Somewhere in the Southern Ocean – April 2016

    6
    Collaboration leads to some deep discussions about data. Image Gloria Salgado Gispert.

    40 scientists walk onto a ship…

    Investigator’s great capacity for work has allowed three separate projects to be combined on this voyage to study the Southern Ocean, from the deep ocean high into the atmosphere above.

    The mixing pot of scientists, gathered on board from both near and far, leads to the sharing of ideas and knowledge from researchers across multiple disciplines. Importantly, it also gives students on board the chance to learn from world-renown experts in marine and climate science.

    50,000 NM
    West of Fiji, Pacific Ocean – July 2016

    7
    Investigator in tropical waters off Lautoka, Fiji.

    We have better maps of the moon than we do of our sea floor. The advanced mapping technology on Investigator is slowly chipping away at the edges of the unknown on each and every voyage.

    A transit voyage back from Fiji provides scientists with the opportunity to collect seafloor samples and map previously unseen underwater landscapes formed during the break-up of Gondwana.

    8
    https://www.zmescience.com/science/geology/fossilized-scorpion-gondwana-02092013/

    60,000 NM
    East Australian Current, Tasman Sea – November 2016

    9
    A deep-water mooring anchor stack is deployed from the back deck.

    Anchors away! Another mooring is lowered into the ocean. These form part of an important network of monitoring stations in oceans across the planet which feed data into global datasets. This is data that allow us to better understand ocean and climate change.

    Before Investigator, these deployments took smaller ships many voyages back and forth. Now, the ship is loaded up and heads out to complete the job in one go.

    70,000 NM
    Totten Glacier, Antarctica – March 2017

    10
    Investigator gets up close to the ice edge in Antarctica.

    It takes a lot of patience to study glaciers, especially those at the ends of the Earth! It’s a long way down and a long way back. Luckily, they aren’t going anywhere fast.

    Or are they? The science we’re enabling on this voyage will help us find out.

    Since arriving, Investigator has now completed 15 research and transit voyages totalling over 400 days of science at sea.

    80,000 NM
    The Abyss, Coral Sea – June 2017

    11
    Scientists look for signs of life in sediments from the abyss. Image Asher Flatt.

    Marine life can be found in some hard to reach places. Investigator is on a voyage to study life in Australia’s deep ocean abyss off the east coast. Seven Commonwealth Marine Reserves are being mapped and studied. Many of the denizens of the deep discovered are soon to become worldwide science sensations.

    90,000 NM
    North West Shelf, Indian Ocean – November 2017

    12
    Investigator enables unique studies of the biodiversity in our oceans.

    In the warm waters off the coast of Western Australia, Investigator is studying the long term recovery of trawled marine communities. It is part of a circumnavigation of the continent completed during 2017 that saw the ship conduct research in all offshore waters.

    It’s our first big lap but it won’t be our last.

    100,000 NM
    Somewhere in the Southern Ocean – February 2018

    13
    Clocking up the big science miles!

    Deep in the Southern Ocean, returning from its first voyage for 2018, Investigator passes a significant milestone on the ship log.

    100,000 nautical miles!

    That’s about 4.5 laps of the globe (at the equator).

    Across the journey, over 800 scientists, researchers and support staff (including over 100 students) from Australia and over 15 other countries have stepped on board as part of voyage science teams.

    For the 40 members of the science team on board today, it’s business as usual. The science doesn’t stop to celebrate. This is what the ship does. Big science over the big journey to answer the big questions.

    100,001+ NM

    The journey is only just beginning for this ship. It’s still a somewhat precocious teenager. With an operational life stretching out at least 25 years, much more science lies ahead for RV Investigator and our future heroes of science on board.

    Stay tuned for the sequel!

    See the full article here .

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    SKA/ASKAP radio telescope at the Murchison Radio-astronomy Observatory (MRO) in Mid West region of Western Australia

    So what can we expect these new radio projects to discover? We have no idea, but history tells us that they are almost certain to deliver some major surprises.

    Making these new discoveries may not be so simple. Gone are the days when astronomers could just notice something odd as they browse their tables and graphs.

    Nowadays, astronomers are more likely to be distilling their answers from carefully-posed queries to databases containing petabytes of data. Human brains are just not up to the job of making unexpected discoveries in these circumstances, and instead we will need to develop “learning machines” to help us discover the unexpected.

    With the right tools and careful insight, who knows what we might find.

    CSIRO campus

    CSIRO, the Commonwealth Scientific and Industrial Research Organisation, is Australia’s national science agency and one of the largest and most diverse research agencies in the world.

     
  • richardmitnick 11:48 am on April 17, 2018 Permalink | Reply
    Tags: Applied Research & Technology, , , Marriage of a 20keV superconducting XFEL with a 100PW laser, , ,   

    From SPIE: “Marriage of a 20keV superconducting XFEL with a 100PW laser” 

    SPIE

    SPIE

    16 April 2018
    Toshiki Tajima, University of California, Irvine
    Ruxin Li, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences

    A new regime of science at exawatts and zeptoseconds.

    The Chinese national science and technology major infrastructure, Shanghai Coherent Light Facility (SCLF), organized an international review meeting for the Station of Extreme Light (SEL) in Shanghai on July 10, 2017.

    The Shanghai Institute of Applied Physics is building a Soft X-ray Free Electron Laser that is set to open to users in 2019. Credit Michael Banks

    The reviewing committee members included experts in strong-field laser physics, high-energy-density physics, and theoretical physics from Germany, USA, UK, France, Japan, Canada; and China chaired by R. Sauerbrey and N .Wang. The working group, led by Ruxin Li of the Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), has made a series of breakthroughs on high energy, high power, and high-repetition laser system development.

    Reflecting on this, the Review Committee Report1 stated: “The architecture of the laser system of the Optical Parametric Chirped Pulse Amplification (OPCPA) and its interaction with the XFEL are well thought out. The proposed 1023 W/cm2 peak laser power is feasible. The working group has made a series of breakthroughs on high-power laser technologies in the past decades. Their constant effort has resulted in valuable experience, outstanding engineering skills, and international recognition for the group. Their strong track record has laid a strong foundation, which will provide the basis for successful construction of the 100 PW laser system.”

    Based on this, the Committee applauded the work, stating: “The Station of Extreme Light at Shanghai Coherent Light Facility is dedicated to cutting-edge research in strong field science and applications. This includes, for example, astrophysics, nuclear physics, cosmology, and matter under extreme conditions. The combination of the hard XFEL and the world-leading 100PW laser in SEL will initiate exploration of effects such as vacuum birefringence, one of the most prominent strong-field QED effects, acceleration mechanisms leading to ultra-high energy cosmic rays, simulation of black hole physics, and generation of new forms of matter.”

    The developments proposed are based on solid research carried out at SIOM (and other scientific organizations). In particular, the research and development of the OPCPA laser amplifier at the highest power level at SIOM. Shown in Figure 1 is SIOM’s 10PW laser CPA device and the 10PW laser system. The 10PW laser system, Shanghai Superintense-Ultrafast Lasers Facility (SULF), is based on CPA technology and the diameter of the Ti-Sapphire used in the main amplifier is 235mm, which is the largest crystal for the laser manufactured by the scientists at SIOM.

    Based on these developments, SIOM has launched a 100PW laser system, Station for Extreme Light (SEL). This system has two significant salient features. First, the level of its power will be an order of magnitude beyond the planned highest-powered laser, Extreme Light Infrastructure (ELI). Secondly, its design is a combination of the 100PW laser as part of the system in the SCLF’s XFEL. This project received strong endorsement from the International Review Meeting that convened at SCLF of SIOM on July 10, 2017, and was approved by the Government of China. The overall funding level is approximately USD$1.3 Billion.

    Figure 1 10PW laser system in Shanghai pumped by CPA.

    II. Extreme field regime
    The parameters of SEL are well beyond what has so far been available. Table 1 shows typical principal physical parameters. The coherent x-ray energy from the SCLF ranges between 3 to 15 keV (hard x-rays) produced from the superconducting x-ray free electron laser (XFEL). The photon number per pulse of this XFEL is 1012. Its pulse focusability is 200nm with the energy resolution of 0.6eV. The x-ray’s intensity at focus is as high as 1021W/cm2.

    The parameters of the 100PW laser for optical photons are as follows: Its peak power is 100PW, while its focal intensity is as high as 1023W/cm2. (If we can managed to focus better than this, it could go toward 1025W/cm2). While this is a single shot performance, it could deliver the repetition rate of 1Hz of optical laser if the power is at 0.1 to 1PW.

    These parameters by themselves are exciting. However, their coexistence and marriage as a combined unit shows a remarkable capability for future scienctific exploration. The combination of a synchrotron light source and an intense laser was first suggested and conducted in 1990s. Toshiki Tajima suggested that Professor Mamoru Fujiwara at Osaka University make use of the high-energy (8GeV) electrons of the SPRing-8 combined with an intense laser to make extremely high-energy gamma photons, which he did in his lab.2 Since then, the combination of these accelerator-based synchrotron light sources (or even more advanced XFEL with intense lasers) have come a long way. The present SCLF’s marriage of these two will uncover a new regime of science and greatly impact various technologies and applications, such as nuclear photonics and nonlinear interferometry.

    4
    Table 1 shows the schematic layout of the SEL. The interaction of XFEL and the plasma chamber takes place in the experimental area. Figure 3 indicates the 100PW laser based on the OPCPA technology.

    4
    Figure 2: Schematic layout figure of SEL that couples the 100PW laser with the XFEL.

    5
    Figure 3: Details of the amplification stages of the 100PW laser based on OPCPA.

    The scheme of this marriage is seen in the concept of the SEL at which the coherent high-energy x-rays photons are shone in the configuration shown in Figure 2. This way we will be able to observe the interaction of the high-energy x-ray photons and most intense lasers and their developed matter interaction. This will greatly increase the experimental probe of intense laser-matter interaction. The XFEL beam will provide ultra-short MHz x-ray beam with energy range of 3-5keV and significantly large photon number of 1012. Specific x-ray energy of 12.914keV will be used for QED experiments with very low energy spread of 0.6eV. The x-ray beam will collide head-on with the 100PW laser pulse in the experimental chamber. The 100PW laser system contains four beams and each beam reaches the peak power of 25 PW.

    Figure 2 shows that the main laser system will occupy two floors and its power supply and control system are set at different floors. After the four-beam combination, the laser pulse will be sent to the experimental area on the bottom floor. There is a large-size vacuum chamber, where the 100PW laser pulse will be focused to 5μm and collide with the x-ray beam.

    Details of the 100PW laser system are shown in Figure 3. At the core is the OPCPA system. The 100PW laser pulse starts at high temporal laser source, where its temporal synchronization signal comes from the XFEL beam. This source will generate high-quality seed pulses, which will go into the PW level repetition-rate OPCPA front-end. The laser energy will reach 25J and its spectrum width will support 15fs at PW level OPCPA front-end.

    The main amplifier is based on OPCPA technology and it provides 99% energy gain of the whole laser system, which requires sufficient pump energy from a Nd Glass pump laser. The final optics assembly will compress the high-energy of 2500J 4ns laser pulse to 15fs. After the compression, the laser pulse will be sent into the experimental chamber with the peak intensity 1023 W/cm2. As shown in Figure 1, we developed and tested the performance of a high-intensity laser with CPA up to 10PW level.

    III. High Field Science
    The proposed SEL aims to achieve the ultimate in high field science [3],[4],[5]. Here, we describe a simple way to reach that goal.

    The radiation dominance regime (1023 W/cm2) as described in Ref. 2 may be accessible and experimentally explored for the first time in sufficient details with the help of the coherent X-ray probe. As discussed in Sec. 1, if one can focus a bit narrowly, we may be able to enter the so-called QED Quantum regime (~1024 W/cm2)[4],[5].

    The particle acceleration by laser will enter a new regime. The wakefield generation [6] becomes so nonlinear that it enters what is sometimes called the bow-wake regime [7]. This may be relevant to the astrophysical extreme high-energy cosmic ray genesis by AGN (active galactic nuclei) jets [8]. In this regime, the physics of wakefield acceleration and that of the radiation pressure acceleration begin to merge (1023W/cm2)[9],[10]. Thus, the laser pulse should be able to pick up ions as well as electrons to become accelerated. Soon or later, the energy of ions begins to exceed that of electrons and their acceleration should become as coherent as the electron acceleration in this regime. Such acceleration will allow ion accelerators to be smaller. (A broader scope at this regime and slightly higher intensity regime than just mentioned has been reviewed [9].)

    However, it could go much further than that, since the invention of a new compression technique called “thin film compression11.” With this technique, a laser may be compressed to even higher power and intensity such as EW and further by relativistic compression into the shortest possible pulses ever in zs12. We will thus see the continuous manifestation of the Intensity-Pulse Duration Theorem into the extension of EW and zs [13]. It will not only explore strong field QED physics [14],[15], but we will also see the emergence of new phenomena at play in a wider variety of fundamental physics, including: (1) possible search of the proposed “fifth force” [16],[17]; (2) dark matter search by four wave mixing [18]; (3) x-ray wakefield in solid state matter [19] and related x-ray and optical solid state plasmonics [20]; (4) possible testing of the energy dependence of gamma photon propagation speed in a vacuum to test the foundational assumption of the Theory of Special Theory of Relativity [21]; and (5) zeptosecond streaking of the QED process [22].

    Chen et al.[23] suggested the exploration of general relativity using the equivalence principle of acceleration-gravity to test the Hawking-Unruh process.

    IV. Gamma-ray diagnosis and the marriage of XFEL and HFS
    In the issues of high field science, we often enter into the physical processes in higher energies and shorter timescales, which may not be easily resolvable in optical diagnosis. Here, the powerful XFEL’s resolution in time and space come in [24]. X-rays can be also signatures in high intensity experiments such as laser-driven acceleration experiments [25]. A typical display of such interplay may be seen in the diagnostics of the physical processes in the problem of x-ray wakefield acceleration in solid-state matter. In this case, nanoscopic materials with a nanohole structure [20] need to be observed and controlled. The surface of the nanotubes may be exhibiting surface plasmons and polaritons in nanometer size and zs temporal dynamics, best diagnosed by the XFEL. This is but an example of the marriage of a 20keV superconducting XFEL and a 100PW laser. In addition this technology will enhance studies in photon-induced nuclear physics [26] and the treatment of nuclear materials [27] (including nuclear waste), nuclear pharmacology, nuclear biochemistry, and medicine [28],[29].

    Another example is to use gamma photons to mediate the vacuum nonlinearity caused by intense laser pulse to exploit zeptosecond streaking via the gamma photon mediation [22]. In this scheme the presence of intense laser pulse and x-ray photon play a crucial role. If this example elucidates a beginning of exploration of zeptosecond photometric and zeptosecond optics, it would be an achievement comparable of the opening of the femtosecond optics flowing by attosecond optics [30].

    One more example of exploring the proposition was recently made for the Fifth Force [17]. In the Hungarian nuclear experiment, a mysterious photon at the energy of 17MeV was observed. The paper [5] suggested this emission of gamma photon may be due to the unknown force (the Fifth Force). It may be helpful if we can inject a large amount of monoenergetic photons at this energy to see if the reversal of this process of photon emission (i.e. injection of photon) can explore this process more quantitatively. We can check of the fifth force (17MeV gamma)16,17,31 with the process and an outcome of the following, utilizing the energy specific laser induced gamma photon interaction: e + 17MeV gamma → e + X.

    Finally, there is a recent suggestion by Day and Fairbairn [32] that XFEL laser pulses at 3.5keV may be used to investigate the astrophysically observed x-ray excess by fluorescent dark matter. Such an avenue may open up with this device. Such an effort along with the astrophysical observations may become an important interdisciplinary development.

    In order to maximize the success of these implications, we recommend the formation of a broad international collaboration with the organizations and institutions that are engaging in related fields. Learning from these labs in their technologies, practice, and collaborative engagements should reduce risks and duplications and enhance learning and the scope of experience. Collaborations with a variety technology sectors are important both for the execution of experiments and their applications.

    The authors are grateful for close discussions with all the committee members (Naiyan Wang, Roland Sauerbrey, Pisin Chen, See Leang Chin, Thomas Edward Cowan, Thomas Heinzl, Yongfeng Lu, Gerard Mourou, Edmond Turcu, Hitoki Yoneda, Lu Yu) of SEL. The discussions with Profs. T. Tait, K. Abazajian, T. Ebisuzaki, and K. Homma were also very useful. Prof. X. M. Zhang helped with our manuscript.

    References:
    1. Report of the International Review Meeting for Station of Extreme Light (2017).

    2. G. A. Mourou, T. Tajima and S. V. Bulanov, Optics in the relativistic regime, Rev. Mod. Phys. 78, p. 309, 2006.

    3. T. Tajima, K. Mima and H. Baldis, Eds., High-Field Science, Kluwer Academic/Plenum Publishers, New York, NY, 2000.

    4. T. Tajima and G. Mourou, Zettawatt-exawatt lasers and their applications in ultrastrong-field physics, Phys. Rev. ST AB 5, p. 031301, 2002.

    5. G. Mourou and T. Tajima, Summary of the IZEST science and aspiration, Eur. Phys. J. ST 223, pp. 979-984, 2014.

    6. T. Tajima and J. M. Dawson, Laser electron accelerator, Phys. Rev. Lett. 43, p. 267, 1979.

    7. C. K. Lau, P. C. Yeh, O. Luk, J. McClenaghan, T. Ebisuzaki and T. Tajima, Ponderomotive acceleration by relativistic waves, Phys. Rev. ST AB 18, p. 024401, 2015; T. Tajima, Laser acceleration in novel media, Eur. Phys. J. ST 223, pp. 1037-1044, 2014.

    8. T. Ebisuzaki and T. Tajima, Astrophysical ZeV acceleration in the relativistic jet from an accreting supermassive blackhole, Astropart. Phys. 56, pp. 9-15, 2014.

    9. T. Tajima, B. C. Barish, C. P. Barty, S. Bulanov, P. Chen, J. Feldhaus, et al., Science of extreme light infrastructure, AIP Conf. Proc. 1228, pp. 11-35, 2010.

    10. T. Esirkepov, M. Borghesi, S. V. Bulanov, G. Mourou and T. Tajima, Highly efficient relativistic-ion generation in the laser-piston regime, Phys. Rev. Lett. 92, p. 175003, 2004.

    11. G. Mourou, S. Mironov, E. Khazanov and A. Sergeev, Single cycle thin film compressor opening the door to Zeptosecond-Exawatt physics, Eur. Phys. J. ST 223, pp. 1181-1188, 2014.

    12. N. Naumova, J. Nees, I. Sokolov, and G. Mourou, Relativistic generation of isolated attosecond pulses in a λ3 focal volume, Phys. Rev. Lett. 92, p. 063902, 2004.

    13. G. Mourou and T. Tajima, More intense, shorter pulses, Science 331, pp. 41-42, 2011.

    14. M. Marklund and P. K. Shukla, Nonlinear collective effects in photon-photon and photon-plasma interactions, Rev. Mod. Phys. 78, p. 591, 2006.

    15. A. Di Piazza, C. Müller, K. Z. Hatsagortsyan and C. H. Keitel, Extremely high-intensity laser interactions with fundamental quantum systems, Rev. Mod. Phys. 84, p. 1177, 2012.

    16. A. J. Krasznahorkay, M. Csatlós, L. Csige, Z. Gácsi, J. Gulyás, M. Hunyadi, et al., Observation of anomalous internal pair creation in Be 8: a possible indication of a light, neutral boson, Phys. Rev. Lett. 116, p. 042501, 2016.

    17. J. L. Feng, B. Fornal, I. Galon, S. Gardner, J. Smolinsky, T. M. Tait and P. Tanedo, Protophobic fifth-force interpretation of the observed anomaly in Be-8 nuclear transitions, Phys. Rev. Lett. 117, p. 071803, 2016.

    18. K. Homma, D. Habs and T. Tajima, Probing the semi-macroscopic vacuum by higher-harmonic generation under focused intense laser fields, Appl. Phys. B 106, pp. 229-240, 2012.

    19. T. Tajima, Laser acceleration in novel media, Eur. Phys. J. ST 223, pp. 1037-1044, 2014.

    20. X. Zhang, T. Tajima, D. Farinella, Y. Shin, G. Mourou, J. Wheeler and B. Shen, Particle-in-cell simulation of x-ray wakefield acceleration and betatron radiation in nanotubes, Phys. Rev. AB 19, p. 101004, 2016.

    21. T. Tajima, M. Kando and M. Teshima, Feeling the texture of vacuum: laser acceleration toward PeV, Progr. Theor. Phys. 125, pp. 617-631, 2011.

    22. T. Tajima, G. Mourou and K. Nakajima, Laser acceleration, Riv. Nuovo Cim. 40, p. 1, 2017.

    23. P. Chen and G. Mourou, Accelerating plasma mirrors to investigate the black hole information loss paradox, Phys. Rev. Lett. 118, p. 045001, 2017.

    24. C. Pellegrini, A. Marinelli and S. Reiche, The physics of x-ray free-electron lasers, Rev. Mod. Phys. 88, p. 015006, 2016.

    25. S. Corde, K. T. Phuoc, G. Lambert, R. Fitour, V. Malka, A. Rousse and E. Lefebvre, Femtosecond x rays from laser-plasma accelerators, Rev. Mod. Phys. 85, p. 1, 2013.

    26. S. V. Bulanov, T. Z. Esirkepov, M. Kando, H. Kiriyama and K. Kondo, Relativistically strong electromagnetic radiation in a plasma, J. Exp. Theor. Phys. 122, pp. 426-433, 2016.

    27. S. Gales, IZEST meeting presentation, ELI-EP, French Embassy in Tokyo, 2013. https://gargantua.polytechnique.fr/siatel-web/linkto/mICYYYSI7yY6. Accessed 10 November 2017.

    28. D. Habs and U. Köster, Production of medical radioisotopes with high specific activity in photonuclear reactions with γ-beams of high intensity and large brilliance, Appl. Phys. B 103, pp. 501-519, 2011; Ö. Özdemir, Eds., Current Cancer Treatment – Novel Beyond Conventional Approaches, INTECH Open Access Publisher, 2011.

    29. A. Bracco and G. Köerner, Eds., Nuclear Physics for Medicine, Nuclear Physics European Collaboration Committee, 2014.

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    31. T. Tajima, T. Tait, and J. Feng, private comment, 2017.

    32. F. Day and M. Fairbairn, submitted to J. High Energy Phys., 2017.

    See the full article here.

    Please help promote STEM in your local schools.

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  • richardmitnick 8:56 am on April 16, 2018 Permalink | Reply
    Tags: Applied Research & Technology, Attosecond X-ray science, , , , , , XLEAP X-ray Laser-Enhanced Attosecond Pulse generation   

    From European XFEL: “Entering the realm of attosecond X-ray science” 

    XFEL bloc

    European XFEL

    European XFEL

    2018/04/13

    New methods for producing and characterizing attosecond X-ray pulses.

    1
    Ultrashort X-ray pulses (pink) at the Linac Coherent Light Source ionize neon gas at the center of a ring of detectors. An infrared laser (orange) sweeps the outgoing electrons (blue) across the detectors with circularly polarized light. Scientists read data from the detectors to learn about the time and energy structure of the pulses, information they will need for future experiments. Copyright: Terry Anderson / SLAC National Accelerator Laboratory.

    SLAC/LCLS

    European XFEL produces unfathomably fast X-ray pulses that are already being used by scientists to explore the unchartered territory of the atomic and molecular cosmos. Intense X-ray pulses lasting only a few femtoseconds – or a few millionths of a billionth of a second – are being used to reveal insights into the dynamics of chemical reactions and the atomic structures of biological molecules such as proteins and viruses. And while there is much more to discover in this femtosecond time range, scientists are already looking to take European XFEL to the next time dimension, exploring reactions and dynamics that occur on an even briefer time scale – the attosecond time regime.

    If you leave the shutter of your camera open for too long while photographing a race, the resulting pictures will only be a smear of colour. To capture clear and sharp images of the athletes’ movements you need to make sure the shutter is only open for the shortest time; in fact the best shutter speed to capture a clear snapshot of the runners’ legs frozen in action would be faster than the time the runner needed to move their legs. Good light conditions help too to make sure your photos are sharp and in focus. And so it is as scientists attempt to take snapshots of some of nature’s fastest processes such as the movements of electrons within atoms and molecules. To capture snapshots of these movements in action we need pulses of intense X-rays that reflect the timescale on which these reactions occur – and these reactions can occur even down to the attosecond timescale.

    XLEAP

    Attosecond X-ray science is expected to allow scientists to delve even deeper into ultrafast chemical and molecular processes and the tiniest details of our world than already possible. But how to produce X-ray flashes that are even shorter than the already ultrafast femtosecond flashes? One of the methods currently being explored by scientists is ‘X-ray Laser-Enhanced Attosecond Pulse generation’ (XLEAP). The method, being developed at the SLAC National Accelerator Laboratory in the USA, is expected to be possible with only moderate modifications to the layout of existing FEL facilities. If successful, the usually chaotic time and energy structure of XFEL (X-ray Free-Electron Laser) pulses, consisting of a sequence of many intensity spikes based on the so-called SASE (Self-Amplification by Spontaneous Emission) principle, can be reliably narrowed down to one single, coherent intensity spike of only few hundreds of attoseconds. In a recent review article in the Journal of Optics, European XFEL scientists propose how the XLEAP method might be implemented at the SASE 3 branch of the facility, eventually providing attosecond pulses for experiments.

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    European XFEL scientist Markus Ilchen working on the original angle resolving time-of-flight spectrometer at PETRA III, DESY. Copyright: European XFEL

    DESY Petra III


    DESY Petra III interior

    Angular Streaking diagnostics

    While the free-electron laser technology is almost ready to provide attosecond pulses, another hurdle is to actually prove and characterize their existence. Experiments to date at XFEL facilities have often relied on indirect measurements and simulations of X-ray pulses to calibrate results. However, only with detailed information from direct measurements of the exact time and energy structure of each X-ray pulse, can X-ray science enter a new era of time resolved and coherence dependent experiments.

    With this in mind, a novel experimental approach was conceived as part of an international collaboration including scientists from SLAC, Deutsches Elektronen-Synchrotron (DESY), European XFEL, the Technical University of Munich, University of Kassel, University of Gothenburg, University of Bern, University of Colorado, University of the Basque Country in Spain, and Lomonosov Moscow State University in Russia. In a study published in the journal Nature Photonics, the international groupdemonstrated the capability of a so-called ‘angular streaking’ method to characterize the time and energy structure of X-ray spikes. The scientists used the shortest pulses available at the Linac Coherent Light Source (LCLS) at SLAC in the USA for their experiment. Using the new angular streaking diagnostic method, millions of pulses, each of a few femtoseconds in length, were successfully captured and analyzed. “Being able to get the precise information about the energy spectrum, as well as the time and intensity structure of every single X-ray pulse is unprecedented” explains Markus Ilchen from the Small Quantum Systems group at European XFEL, one of the principal investigators of this work. “This is really one of the holy grails of FEL diagnostics” he adds enthusiastically.

    The new angular streaking technique works by using the rotating electrical field of intense circularly polarized optical laser pulses to extract the time and energy structure of the XFEL pulses. Interaction with the XFEL pulse causes atoms to eject electrons which are then strongly kicked around by the surrounding laser field. Information about the electron’s exact time of birth is not only imprinted in the energy of the electron but also in the ejecting angle. This all provides a ‘clock’ by which to sort the resulting experimental data. Pulses generated by the SASE process, as implemented at European XFEL and SLAC, are intrinsically variable and chaotic. Some of the recorded pulses during the experiment at SLAC were, therefore, already single spikes in the attosecond regime which then were fully characterized for their time-energy structure.

    Angle resolving time-of-flight spectrometer

    1
    An illustration of the ring-shaped array of 16 individual detectors arranged in a circle like numbers on the face of a clock. An X-ray laser pulse hits a target at the center and sets free electrons that are swept around the detectors. The location, where the electrons reach the “clock,” reveals details such as the variation of the X-ray energy and intensity as a function of time within the ultrashort pulse itself. Copyright: Frank Scholz & Jens Buck, DESY.

    he underlying spectroscopic method is based on an angle resolving time-of-flight spectrometer setup consisting of 16 individual spectrometers aligned in a plane perpendicular to the XFEL beam. These are used to characterize the X-ray beam by correlating the electrons’ energies and their angle dependent intensities. An adapted version of the spectrometer setup originally developed at the PETRA III storage ring at DESY, was built in the diagnostics group of European XFEL and provided for the beamtime at SLAC.

    At European XFEL the diagnostic goal is that scientists will eventually be able to use the method to extract all information online during their experiments and correlate and adjust their data analysis accordingly. Furthermore, although the method has so far only been designed and tested for soft X-rays, Ilchen and his colleagues are optimistic that it could also be used for experiments using hard X-rays. “By reducing the wavelength of the optical laser, we could even resolve the few hundreds of attosecond broad spikes of the hard X-ray pulses here at the SASE 1 branch of European XFEL” Ilchen says.

    Time-resolved experiments

    During the experiment at SLAC the scientists also showed that it was even possible to use the acquired data to select pulses with exactly two intensity spikes with a variable time delay between them. This demonstrates the capability of FELs to enable time-resolved X-ray measurements attosecond to few femtosecond delay. “By determining the time duration and distance of those two spikes, we can sort our data for matching pulse properties and use them to understand how certain reactions and processes have progressed on an attosecond timescale” explains Ilchen. “Since our method gives us precise information about the pulse structure, we will be able to reliably reconstruct what is happening in our samples by producing a sequence of snapshots, so that much like a series of photographs pasted together makes a moving film sequence, we can make ‘movies’ of the reactions” he adds.

    From principle to proof

    Due to the limited pulse repetition rate currently available at most XFELs, however, moving from a proof-of-principle experiment to actually using specifically structured pulses for so-called pump-probe experiments requires a large leap of the imagination. European XFEL, however, already provides more pulses per second than other similar facilities, and will eventually provide 27,000 pulses per second, making the dream of attosecond time-resolved experiment a real possibility. “Although, currently, no machine in the world can provide attosecond X-ray pulses with variable time delay below the femtosecond regime in a controlled fashion,” says Ilchen, “the technologies available at European XFEL in combination with our method, could enable us to produce so much data that we can pick the pulse structures of interest and sort the rest out while still getting enough statistics for new scientific perspectives.”

    Further reading:

    News from SLAC – “Tick, Tock on the ‘Attoclock’: Tracking X-Ray Laser Pulses at Record Speeds

    Overview of options for generating high-brightness attosecond x-ray pulses at free-electron lasers and applications at the European XFEL
    S. Serkez et al., Journal of Optics, 9 Jan 2018 doi:10.1088/2040-8986/aa9f4f

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    XFEL Campus

    XFEL Tunnel

    XFEL Gun

    The Hamburg area will soon boast a research facility of superlatives: The European XFEL will generate ultrashort X-ray flashes—27 000 times per second and with a brilliance that is a billion times higher than that of the best conventional X-ray radiation sources.

    The outstanding characteristics of the facility are unique worldwide. Started in 2017, it will open up completely new research opportunities for scientists and industrial users.

     
  • richardmitnick 4:04 pm on April 14, 2018 Permalink | Reply
    Tags: Applied Research & Technology, , , , , , , ,   

    From Monash U and OzGrav via Science Alert: “We Could Detect Black Hole Collisions All The Time With This Amazing New Method” 

    Monash Univrsity bloc

    Monash University

    1

    OzGrav

    Science Alert

    2
    (LIGO/Caltech/MIT/Sonoma State (Aurore Simonnet)

    13 APR 2018
    MICHELLE STARR

    Black holes could be making cataclysmic collisions across the Universe every few minutes. Unfortunately, the aftermath is too faint to alert our current detection technology.

    But a clever new technique could allow us to “hear” these collisions by finding their signals in the background static that LIGO-Virgo’s detectors are picking up all the time.

    Even though we humans can’t hear any sounds coming from space, the gravitational wave signal of two black holes or neutron stars colliding can be translated into a sound wave.

    This has been done for the six confirmed gravitational wave signals picked up since that first groundbreaking detection in 2015.

    But these events are much more frequent than we have detected to date, according to Eric Thrane and Rory Smith of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) and Monash University.

    Both of these researchers participated in that first discovery, as well as last year’s jaw-dropping neutron star collision.

    UC Santa Cruz

    UC Santa Cruz

    14

    A UC Santa Cruz special report

    Tim Stephens

    Astronomer Ryan Foley says “observing the explosion of two colliding neutron stars” [see https://sciencesprings.wordpress.com/2017/10/17/from-ucsc-first-observations-of-merging-neutron-stars-mark-a-new-era-in-astronomy ]–the first visible event ever linked to gravitational waves–is probably the biggest discovery he’ll make in his lifetime. That’s saying a lot for a young assistant professor who presumably has a long career still ahead of him.

    2
    The first optical image of a gravitational wave source was taken by a team led by Ryan Foley of UC Santa Cruz using the Swope Telescope at the Carnegie Institution’s Las Campanas Observatory in Chile. This image of Swope Supernova Survey 2017a (SSS17a, indicated by arrow) shows the light emitted from the cataclysmic merger of two neutron stars. (Image credit: 1M2H Team/UC Santa Cruz & Carnegie Observatories/Ryan Foley)

    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

    A neutron star forms when a massive star runs out of fuel and explodes as a supernova, throwing off its outer layers and leaving behind a collapsed core composed almost entirely of neutrons. Neutrons are the uncharged particles in the nucleus of an atom, where they are bound together with positively charged protons. In a neutron star, they are packed together just as densely as in the nucleus of an atom, resulting in an object with one to three times the mass of our sun but only about 12 miles wide.

    “Basically, a neutron star is a gigantic atom with the mass of the sun and the size of a city like San Francisco or Manhattan,” said Foley, an assistant professor of astronomy and astrophysics at UC Santa Cruz.

    These objects are so dense, a cup of neutron star material would weigh as much as Mount Everest, and a teaspoon would weigh a billion tons. It’s as dense as matter can get without collapsing into a black hole.

    THE MERGER

    Like other stars, neutron stars sometimes occur in pairs, orbiting each other and gradually spiraling inward. Eventually, they come together in a catastrophic merger that distorts space and time (creating gravitational waves) and emits a brilliant flare of electromagnetic radiation, including visible, infrared, and ultraviolet light, x-rays, gamma rays, and radio waves. Merging black holes also create gravitational waves, but there’s nothing to be seen because no light can escape from a black hole.

    Foley’s team was the first to observe the light from a neutron star merger that took place on August 17, 2017, and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO).


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    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

    1
    Skymap showing how adding Virgo to LIGO helps in reducing the size of the source-likely region in the sky. (Credit: Giuseppe Greco (Virgo Urbino group)

    Now, for the first time, scientists can study both the gravitational waves (ripples in the fabric of space-time), and the radiation emitted from the violent merger of the densest objects in the universe.

    3
    The UC Santa Cruz team found SSS17a by comparing a new image of the galaxy N4993 (right) with images taken four months earlier by the Hubble Space Telescope (left). The arrows indicate where SSS17a was absent from the Hubble image and visible in the new image from the Swope Telescope. (Image credits: Left, Hubble/STScI; Right, 1M2H Team/UC Santa Cruz & Carnegie Observatories/Ryan Foley)

    It’s that combination of data, and all that can be learned from it, that has astronomers and physicists so excited. The observations of this one event are keeping hundreds of scientists busy exploring its implications for everything from fundamental physics and cosmology to the origins of gold and other heavy elements.


    A small team of UC Santa Cruz astronomers were the first team to observe light from two neutron stars merging in August. The implications are huge.

    ALL THE GOLD IN THE UNIVERSE

    It turns out that the origins of the heaviest elements, such as gold, platinum, uranium—pretty much everything heavier than iron—has been an enduring conundrum. All the lighter elements have well-explained origins in the nuclear fusion reactions that make stars shine or in the explosions of stars (supernovae). Initially, astrophysicists thought supernovae could account for the heavy elements, too, but there have always been problems with that theory, says Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz.

    4
    The violent merger of two neutron stars is thought to involve three main energy-transfer processes, shown in this diagram, that give rise to the different types of radiation seen by astronomers, including a gamma-ray burst and a kilonova explosion seen in visible light. (Image credit: Murguia-Berthier et al., Science)

    A theoretical astrophysicist, Ramirez-Ruiz has been a leading proponent of the idea that neutron star mergers are the source of the heavy elements. Building a heavy atomic nucleus means adding a lot of neutrons to it. This process is called rapid neutron capture, or the r-process, and it requires some of the most extreme conditions in the universe: extreme temperatures, extreme densities, and a massive flow of neutrons. A neutron star merger fits the bill.

    Ramirez-Ruiz and other theoretical astrophysicists use supercomputers to simulate the physics of extreme events like supernovae and neutron star mergers. This work always goes hand in hand with observational astronomy. Theoretical predictions tell observers what signatures to look for to identify these events, and observations tell theorists if they got the physics right or if they need to tweak their models. The observations by Foley and others of the neutron star merger now known as SSS17a are giving theorists, for the first time, a full set of observational data to compare with their theoretical models.

    According to Ramirez-Ruiz, the observations support the theory that neutron star mergers can account for all the gold in the universe, as well as about half of all the other elements heavier than iron.

    RIPPLES IN THE FABRIC OF SPACE-TIME

    Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity, but until recently they were impossible to observe. LIGO’s extraordinarily sensitive detectors achieved the first direct detection of gravitational waves, from the collision of two black holes, in 2015. Gravitational waves are created by any massive accelerating object, but the strongest waves (and the only ones we have any chance of detecting) are produced by the most extreme phenomena.

    Two massive compact objects—such as black holes, neutron stars, or white dwarfs—orbiting around each other faster and faster as they draw closer together are just the kind of system that should radiate strong gravitational waves. Like ripples spreading in a pond, the waves get smaller as they spread outward from the source. By the time they reached Earth, the ripples detected by LIGO caused distortions of space-time thousands of times smaller than the nucleus of an atom.

    The rarefied signals recorded by LIGO’s detectors not only prove the existence of gravitational waves, they also provide crucial information about the events that produced them. Combined with the telescope observations of the neutron star merger, it’s an incredibly rich set of data.

    LIGO can tell scientists the masses of the merging objects and the mass of the new object created in the merger, which reveals whether the merger produced another neutron star or a more massive object that collapsed into a black hole. To calculate how much mass was ejected in the explosion, and how much mass was converted to energy, scientists also need the optical observations from telescopes. That’s especially important for quantifying the nucleosynthesis of heavy elements during the merger.

    LIGO can also provide a measure of the distance to the merging neutron stars, which can now be compared with the distance measurement based on the light from the merger. That’s important to cosmologists studying the expansion of the universe, because the two measurements are based on different fundamental forces (gravity and electromagnetism), giving completely independent results.

    “This is a huge step forward in astronomy,” Foley said. “Having done it once, we now know we can do it again, and it opens up a whole new world of what we call ‘multi-messenger’ astronomy, viewing the universe through different fundamental forces.”

    IN THIS REPORT

    Neutron stars
    A team from UC Santa Cruz was the first to observe the light from a neutron star merger that took place on August 17, 2017 and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)

    5
    Graduate students and post-doctoral scholars at UC Santa Cruz played key roles in the dramatic discovery and analysis of colliding neutron stars.Astronomer Ryan Foley leads a team of young graduate students and postdoctoral scholars who have pulled off an extraordinary coup. Following up on the detection of gravitational waves from the violent merger of two neutron stars, Foley’s team was the first to find the source with a telescope and take images of the light from this cataclysmic event. In so doing, they beat much larger and more senior teams with much more powerful telescopes at their disposal.

    “We’re sort of the scrappy young upstarts who worked hard and got the job done,” said Foley, an untenured assistant professor of astronomy and astrophysics at UC Santa Cruz.

    7
    David Coulter, graduate student

    The discovery on August 17, 2017, has been a scientific bonanza, yielding over 100 scientific papers from numerous teams investigating the new observations. Foley’s team is publishing seven papers, each of which has a graduate student or postdoc as the first author.

    “I think it speaks to Ryan’s generosity and how seriously he takes his role as a mentor that he is not putting himself front and center, but has gone out of his way to highlight the roles played by his students and postdocs,” said Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz and the most senior member of Foley’s team.

    “Our team is by far the youngest and most diverse of all of the teams involved in the follow-up observations of this neutron star merger,” Ramirez-Ruiz added.

    8
    Charles Kilpatrick, postdoctoral scholar

    Charles Kilpatrick, a 29-year-old postdoctoral scholar, was the first person in the world to see an image of the light from colliding neutron stars. He was sitting in an office at UC Santa Cruz, working with first-year graduate student Cesar Rojas-Bravo to process image data as it came in from the Swope Telescope in Chile. To see if the Swope images showed anything new, he had also downloaded “template” images taken in the past of the same galaxies the team was searching.

    9
    Ariadna Murguia-Berthier, graduate student

    “In one image I saw something there that was not in the template image,” Kilpatrick said. “It took me a while to realize the ramifications of what I was seeing. This opens up so much new science, it really marks the beginning of something that will continue to be studied for years down the road.”

    At the time, Foley and most of the others in his team were at a meeting in Copenhagen. When they found out about the gravitational wave detection, they quickly got together to plan their search strategy. From Copenhagen, the team sent instructions to the telescope operators in Chile telling them where to point the telescope. Graduate student David Coulter played a key role in prioritizing the galaxies they would search to find the source, and he is the first author of the discovery paper published in Science.

    10
    Matthew Siebert, graduate student

    “It’s still a little unreal when I think about what we’ve accomplished,” Coulter said. “For me, despite the euphoria of recognizing what we were seeing at the moment, we were all incredibly focused on the task at hand. Only afterward did the significance really sink in.”

    Just as Coulter finished writing his paper about the discovery, his wife went into labor, giving birth to a baby girl on September 30. “I was doing revisions to the paper at the hospital,” he said.

    It’s been a wild ride for the whole team, first in the rush to find the source, and then under pressure to quickly analyze the data and write up their findings for publication. “It was really an all-hands-on-deck moment when we all had to pull together and work quickly to exploit this opportunity,” said Kilpatrick, who is first author of a paper comparing the observations with theoretical models.

    11
    César Rojas Bravo, graduate student

    Graduate student Matthew Siebert led a paper analyzing the unusual properties of the light emitted by the merger. Astronomers have observed thousands of supernovae (exploding stars) and other “transients” that appear suddenly in the sky and then fade away, but never before have they observed anything that looks like this neutron star merger. Siebert’s paper concluded that there is only a one in 100,000 chance that the transient they observed is not related to the gravitational waves.

    Ariadna Murguia-Berthier, a graduate student working with Ramirez-Ruiz, is first author of a paper synthesizing data from a range of sources to provide a coherent theoretical framework for understanding the observations.

    Another aspect of the discovery of great interest to astronomers is the nature of the galaxy and the galactic environment in which the merger occurred. Postdoctoral scholar Yen-Chen Pan led a paper analyzing the properties of the host galaxy. Enia Xhakaj, a new graduate student who had just joined the group in August, got the opportunity to help with the analysis and be a coauthor on the paper.

    12
    Yen-Chen Pan, postdoctoral scholar

    “There are so many interesting things to learn from this,” Foley said. “It’s a great experience for all of us to be part of such an important discovery.”

    13
    Enia Xhakaj, graduate student

    IN THIS REPORT

    Scientific Papers from the 1M2H Collaboration

    Coulter et al., Science, Swope Supernova Survey 2017a (SSS17a), the Optical Counterpart to a Gravitational Wave Source

    Drout et al., Science, Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis

    Shappee et al., Science, Early Spectra of the Gravitational Wave Source GW170817: Evolution of a Neutron Star Merger

    Kilpatrick et al., Science, Electromagnetic Evidence that SSS17a is the Result of a Binary Neutron Star Merger

    Siebert et al., ApJL, The Unprecedented Properties of the First Electromagnetic Counterpart to a Gravitational-wave Source

    Pan et al., ApJL, The Old Host-galaxy Environment of SSS17a, the First Electromagnetic Counterpart to a Gravitational-wave Source

    Murguia-Berthier et al., ApJL, A Neutron Star Binary Merger Model for GW170817/GRB170817a/SSS17a

    Kasen et al., Nature, Origin of the heavy elements in binary neutron star mergers from a gravitational wave event

    Abbott et al., Nature, A gravitational-wave standard siren measurement of the Hubble constant (The LIGO Scientific Collaboration and The Virgo Collaboration, The 1M2H Collaboration, The Dark Energy Camera GW-EM Collaboration and the DES Collaboration, The DLT40 Collaboration, The Las Cumbres Observatory Collaboration, The VINROUGE Collaboration & The MASTER Collaboration)

    Abbott et al., ApJL, Multi-messenger Observations of a Binary Neutron Star Merger

    PRESS RELEASES AND MEDIA COVERAGE


    Watch Ryan Foley tell the story of how his team found the neutron star merger in the video below. 2.5 HOURS.

    Press releases:

    UC Santa Cruz Press Release

    UC Berkeley Press Release

    Carnegie Institution of Science Press Release

    LIGO Collaboration Press Release

    National Science Foundation Press Release

    Media coverage:

    The Atlantic – The Slack Chat That Changed Astronomy

    Washington Post – Scientists detect gravitational waves from a new kind of nova, sparking a new era in astronomy

    New York Times – LIGO Detects Fierce Collision of Neutron Stars for the First Time

    Science – Merging neutron stars generate gravitational waves and a celestial light show

    CBS News – Gravitational waves – and light – seen in neutron star collision

    CBC News – Astronomers see source of gravitational waves for 1st time

    San Jose Mercury News – A bright light seen across the universe, proving Einstein right

    Popular Science – Gravitational waves just showed us something even cooler than black holes

    Scientific American – Gravitational Wave Astronomers Hit Mother Lode

    Nature – Colliding stars spark rush to solve cosmic mysteries

    National Geographic – In a First, Gravitational Waves Linked to Neutron Star Crash

    Associated Press – Astronomers witness huge cosmic crash, find origins of gold

    Science News – Neutron star collision showers the universe with a wealth of discoveries

    UCSC press release
    First observations of merging neutron stars mark a new era in astronomy

    Credits

    Writing: Tim Stephens
    Video: Nick Gonzales
    Photos: Carolyn Lagattuta
    Header image: Illustration by Robin Dienel courtesy of the Carnegie Institution for Science
    Design and development: Rob Knight
    Project managers: Sherry Main, Scott Hernandez-Jason, Tim Stephens

    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    Noted in the video but not in the article:

    NASA/Chandra Telescope

    NASA/SWIFT Telescope

    NRAO/Karl V Jansky VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    CTIO PROMPT telescope telescope built by the University of North Carolina at Chapel Hill at Cerro Tololo Inter-American Observatory in Chilein the Chilean Andes.

    PROMPT The six domes at CTIO in Chile.

    NASA NuSTAR X-ray telescope

    See the full article here .

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    UCO Lick Shane Telescope
    UCO Lick Shane Telescope interior
    Shane Telescope at UCO Lick Observatory, UCSC

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

    UC Santa Cruz campus
    The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

    UCSC is the home base for the Lick Observatory.

    Lick Observatory's Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building
    Lick Observatory’s Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building

    Search for extraterrestrial intelligence expands at Lick Observatory
    New instrument scans the sky for pulses of infrared light
    March 23, 2015
    By Hilary Lebow
    1
    The NIROSETI instrument saw first light on the Nickel 1-meter Telescope at Lick Observatory on March 15, 2015. (Photo by Laurie Hatch) UCSC Lick Nickel telescope

    Astronomers are expanding the search for extraterrestrial intelligence into a new realm with detectors tuned to infrared light at UC’s Lick Observatory. A new instrument, called NIROSETI, will soon scour the sky for messages from other worlds.

    “Infrared light would be an excellent means of interstellar communication,” said Shelley Wright, an assistant professor of physics at UC San Diego who led the development of the new instrument while at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics.

    Wright worked on an earlier SETI project at Lick Observatory as a UC Santa Cruz undergraduate, when she built an optical instrument designed by UC Berkeley researchers. The infrared project takes advantage of new technology not available for that first optical search.

    Infrared light would be a good way for extraterrestrials to get our attention here on Earth, since pulses from a powerful infrared laser could outshine a star, if only for a billionth of a second. Interstellar gas and dust is almost transparent to near infrared, so these signals can be seen from great distances. It also takes less energy to send information using infrared signals than with visible light.

    5
    UCSC alumna Shelley Wright, now an assistant professor of physics at UC San Diego, discusses the dichroic filter of the NIROSETI instrument. (Photo by Laurie Hatch)

    Frank Drake, professor emeritus of astronomy and astrophysics at UC Santa Cruz and director emeritus of the SETI Institute, said there are several additional advantages to a search in the infrared realm.

    “The signals are so strong that we only need a small telescope to receive them. Smaller telescopes can offer more observational time, and that is good because we need to search many stars for a chance of success,” said Drake.

    The only downside is that extraterrestrials would need to be transmitting their signals in our direction, Drake said, though he sees this as a positive side to that limitation. “If we get a signal from someone who’s aiming for us, it could mean there’s altruism in the universe. I like that idea. If they want to be friendly, that’s who we will find.”

    Scientists have searched the skies for radio signals for more than 50 years and expanded their search into the optical realm more than a decade ago. The idea of searching in the infrared is not a new one, but instruments capable of capturing pulses of infrared light only recently became available.

    “We had to wait,” Wright said. “I spent eight years waiting and watching as new technology emerged.”

    Now that technology has caught up, the search will extend to stars thousands of light years away, rather than just hundreds. NIROSETI, or Near-Infrared Optical Search for Extraterrestrial Intelligence, could also uncover new information about the physical universe.

    “This is the first time Earthlings have looked at the universe at infrared wavelengths with nanosecond time scales,” said Dan Werthimer, UC Berkeley SETI Project Director. “The instrument could discover new astrophysical phenomena, or perhaps answer the question of whether we are alone.”

    NIROSETI will also gather more information than previous optical detectors by recording levels of light over time so that patterns can be analyzed for potential signs of other civilizations.

    “Searching for intelligent life in the universe is both thrilling and somewhat unorthodox,” said Claire Max, director of UC Observatories and professor of astronomy and astrophysics at UC Santa Cruz. “Lick Observatory has already been the site of several previous SETI searches, so this is a very exciting addition to the current research taking place.”

    NIROSETI will be fully operational by early summer and will scan the skies several times a week on the Nickel 1-meter telescope at Lick Observatory, located on Mt. Hamilton east of San Jose.

    The NIROSETI team also includes Geoffrey Marcy and Andrew Siemion from UC Berkeley; Patrick Dorval, a Dunlap undergraduate, and Elliot Meyer, a Dunlap graduate student; and Richard Treffers of Starman Systems. Funding for the project comes from the generous support of Bill and Susan Bloomfield.

    UCSC is the home base for the Lick Observatory.

    When two black holes or neutron stars collide, the event is so massive and disruptive that it sends gravitational waves rippling out across the fabric of space-time.

    Although predicted by Einstein’s theory of general relativity in 1915, it wasn’t until 100 years later that we were able to develop instrumentation sensitive enough to detect these ripples.

    The technology is still in its infancy and is being refined over time. This means, potentially, that there is a lot we still can’t detect.

    Every year, the researchers say, there are over 100,000 gravitational wave events that are too faint for the interferometers of the LIGO-Virgo collaboration to detect unambiguously.

    These are caused by smaller black hole collisions, and collisions much farther away. Rather than showing up as individual signal spikes, their signals resolve into a sort of “hum”.

    Researchers have been trying to find this hum for years – and now Thrane, Smith and their team believe they may have developed a method sensitive enough to detect it among the gravitational wave background static picked up by the interferometers.

    “Measuring the gravitational-wave background will allow us to study populations of black holes at vast distances,” Thrane said.

    “Someday, the technique may enable us to see gravitational waves from the Big Bang, hidden behind gravitational waves from black holes and neutron stars.”

    The team has developed an algorithm that can comb through the LIGO-Virgo static data and pick out the signals of the black hole collisions – when converted to audio, it’s an upsweep of sound that ends in a sort of loud “BLOOP.”

    “It’s the same thing your brain does when your car radio goes out of reception and goes to static,” Smith told the Sydney Morning Herald.

    “Little bits and pieces of radio stations still come through – but your brain is able to put them together and work out what song is playing.”

    To test it, they created simulations of black hole collisions, then had their algorithm try to pick them out of background static.

    They found that it wasn’t fooled by artefacts such as background glitches, and was reliably able to pick out unpredictable signals.

    It has yet to be applied to real data, but the researchers are confident it will work, especially run on a powerful new supercomputer at Swinburne University.

    OzSTAR, with a peak performance of 1.2 petaflops, will be used to sort through the vast amounts of data being generated by gravitational wave detectors, looking for black hole and neutron star mergers in real-time.

    “It gives us a taste of the universe at its most extreme,” Matthew Bailes, director of OzGrav, told the ABC.

    “It’s when you’ve sort of set the laws of physics to ‘stun’, and to a physicist that is an exciting place to probe.”

    The team’s research has been accepted into the journal Physical Review X.

    See the full article here .

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    Monash U campus

    Monash University (/ˈmɒnæʃ/) is an Australian public research university based in Melbourne, Australia. Founded in 1958, it is the second oldest university in the State of Victoria. Monash is a member of Australia’s Group of Eight and the ASAIHL, and is the only Australian member of the influential M8 Alliance of Academic Health Centers, Universities and National Academies. Monash is one of two Australian universities to be ranked in the The École des Mines de Paris (Mines ParisTech) ranking on the basis of the number of alumni listed among CEOs in the 500 largest worldwide companies.[6] Monash is in the top 20% in teaching, top 10% in international outlook, top 20% in industry income and top 10% in research in the world in 2016.[7]

    Monash enrolls approximately 47,000 undergraduate and 20,000 graduate students,[8] It also has more applicants than any university in the state of Victoria.

    Monash is home to major research facilities, including the Australian Synchrotron, the Monash Science Technology Research and Innovation Precinct (STRIP), the Australian Stem Cell Centre, 100 research centres[9] and 17 co-operative research centres. In 2011, its total revenue was over $2.1 billion, with external research income around $282 million.[10]

    The university has a number of centres, five of which are in Victoria (Clayton, Caulfield, Berwick, Peninsula, and Parkville), one in Malaysia.[11] Monash also has a research and teaching centre in Prato, Italy,[12] a graduate research school in Mumbai, India[13] and a graduate school in Jiangsu Province, China.[14] Since December 2011, Monash has had a global alliance with the University of Warwick in the United Kingdom.[15] Monash University courses are also delivered at other locations, including South Africa.

    The Clayton campus contains the Robert Blackwood Hall, named after the university’s founding Chancellor Sir Robert Blackwood and designed by Sir Roy Grounds.[16]

    In 2014, the University ceded its Gippsland campus to Federation University.[17] On 7 March 2016, Monash announced that it would be closing the Berwick campus by 2018.

     
  • richardmitnick 3:37 pm on April 14, 2018 Permalink | Reply
    Tags: Applied Research & Technology, , , ,   

    From LBNL: “Valleytronics Discovery Could Extend Limits of Moore’s Law” 

    Berkeley Logo

    Berkeley Lab

    April 13, 2018
    John German
    jdgerman@lbl.gov
    (510) 486-6601

    1
    Valleytronics utilizes different local energy extrema (valleys) with selection rules to store 0s and 1s. In SnS, these extrema have different shapes and responses to different polarizations of light, allowing the 0s and 1s to be directly recognized. This schematic illustrates the variation of electron energy in different states, represented by curved surfaces in space. The two valleys of the curved surface are shown. No image credit.

    Research appearing today in Nature Communications finds useful new information-handling potential in samples of tin(II) sulfide (SnS), a candidate “valleytronics” transistor material that might one day enable chipmakers to pack more computing power onto microchips.

    The research was led by Jie Yao of the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and Shuren Lin of UC Berkeley’s Department of Materials Science and Engineering and included scientists from Singapore and China. The research team used the unique capabilities of Berkeley Lab’s Molecular Foundry, a DOE Office of Science user facility.

    For several decades, improvements in conventional transistor materials have been sufficient to sustain Moore’s Law – the historical pattern of microchip manufacturers packing more transistors (and thus more information storage and handling capacity) into a given volume of silicon. Today, however, chipmakers are concerned that they might soon reach the fundamental limits of conventional materials. If they can’t continue to pack more transistors into smaller spaces, they worry that Moore’s Law would break down, preventing future circuits from becoming smaller and more powerful than their predecessors.

    That’s why researchers worldwide are on the hunt for new materials that can compute in smaller spaces, primarily by taking advantage of the additional degrees of freedom that the materials offer – in other words, using a material’s unique properties to perform more computations in the same space. Spintronics, for example, is a concept for transistors that harnesses the up and down spins of electrons in materials as the on/off transistor states.

    Valleytronics, another emerging approach, utilizes the highly selective response of candidate crystalline materials under specific illumination conditions to denote their on/off states – that is, using the materials’ band structures so that the information of 0s and 1s is stored in separate energy valleys of electrons, which are dependent on the crystal structures of the materials.

    In this new study, the research team has shown that tin(II) sulfide (SnS) is able to absorb different polarizations of light and then selectively reemit light of different colors at different polarizations. This is useful for concurrently accessing both the usual electronic and valleytronic degrees of freedom, which would substantially increase the computing power and data storage density of circuits made with the material.

    “We show a new material with distinctive energy valleys that can be directly identified and separately controlled,” said Yao. “This is important because it provides us a platform to understand how valley signatures are carried by electrons and how information can be easily stored and processed between the valleys, which are of both scientific and engineering significance.”

    Lin, the first author of the paper, said the material is different from previously investigated candidate valleytronics materials because it possesses such selectivity at room temperature without additional biases apart from the excitation light source, which alleviates the previously stringent requirements in controlling the valleys. Compared to its predecessor materials, SnS is also much easier to process.

    With this finding, researchers will be able to develop operational valleytronic devices, which may one day be integrated into electronic circuits. The unique coupling between light and valleys in this new material may also pave the way toward future hybrid electronic/photonic chips.

    Berkeley Lab’s “Beyond Moore’s Law” initiative leverages the basic science capabilities and unique user facilities of Berkeley Lab and UC Berkeley to evaluate promising candidates for next-generation electronics and computing technologies. Its objective is to build close partnerships with industry to accelerate the time it typically takes to move from the discovery of a technology to its scale-up and commercialization.

    See the full article here .

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

    University of California Seal

    DOE Seal

     
  • richardmitnick 11:20 am on April 11, 2018 Permalink | Reply
    Tags: Applied Research & Technology, Shaking up megathrust earthquakes with slow slip and fluid drainage,   

    From Tokyo Institute of Technology: “Shaking up megathrust earthquakes with slow slip and fluid drainage” 

    tokyo-tech-bloc

    April 10, 2018

    Further Information
    Professor Junichi Nakajima
    School of Science,
    Tokyo Institute of Technology
    Email nakajima@geo.titech.ac.jp

    Contact
    Public Relations Section,
    Tokyo Institute of Technology
    media@jim.titech.ac.jp
    Tel +81-3-5734-2975

    Megathrust earthquakes are the most powerful type of earthquake, occurring at subduction zones – where one tectonic plate is pushed beneath another. By contrast, slow slip events (SSEs) release seismic stress at a lower rate than large earthquakes, re-occurring in cycles (across months to years). These processes can take place along the megathrust and other planes of weakness in response to loading, releasing low frequency seismic waves. Researchers at Tokyo Tech and Tohoku University consider the fluid drainage processes that can occur from SSEs and their impact on seismic activity.

    1
    Figure 1. Seismicity from 2004 to 2015 along the Philippine Sea slab. a — seismic activity from 2004-2015 along the Philippine Sea slab, b — relocated earthquakes, c — cross section along sample area (a-b), d — frequency magnitude distribution.

    While the drainage of fluids during megathrust earthquakes has been thought to occur when the megathrusts open up new pathways for fluid drainage through deformation, little has been understood on whether such fluid movements occur as a result of SSEs. Professor Junichi Nakajima at Tokyo Tech and Associate Professor Naoki Uchida at Tohoku University have suggested that fluid drainage resulting from slow slip may be an additional contributor to megathrust seismic activity.

    The team investigated the relationship between SSEs and seismic activity, while analyzing a rich dataset of seismic events around the Philippine Sea Plate. As shown in their recent publication in Nature Geoscience, the scientists analyzed waveform data from beneath Kanto, Japan, dating from 2004 to 2015 (as shown in Figure 1). They traced the boundary of the plate, to indicate when repeating earthquakes occurred in time, while correlating seismic activity with estimated slip-rates (as shown in Figure 2). They infer, through their analysis, that seismic activity above the megathrust of the Philippine Sea slab varied in response to SSEs, through episodic cycles. The scientists estimated intensive draining processes during SSEs, repeating at one year intervals; accompanied with fluid transport into the overlying plate.

    2
    Figure 2. Correlations of supraslab earthquakes and megathrust slip rates. The number of supra-slab earthquakes, b- average slip rates on the megathrust, c- cross-correlation between supraslab seismicity and megathrust slip rates.

    In their publication, they discuss how pore-fluid pressures play a role, emphasizing that areas of slow slip tend to have extremely high pore fluid pressures, and thus have a high potential to release fluids into other portions of the rock bodies. It is suggested SSEs could cause the movement of fluid into overlying rock units (if there were enough fracture or pore space to do so), inducing weakness in these areas and triggering seismicity.

    Based on this idea, the scientists speculate that if the overlying plate were impermeable (with no suitable spaces for fluid to move into), then fluid would be forced to travel through the mega thrust itself (rather than surrounding rock pores or fractures). This could in turn, help to trigger megathrust earthquake events as a result. Therefore, slow slip could catalyze seismic activity in megathrusts. While stress modulation are important contributors to megathrust-induced seismic activity, fluid transfer by episodic SSE may play a greater role than previously thought.

    Science paper:
    Repeated drainage from megathrusts during episodic slow slip
    Nature Geoscience

    See the full article here .

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    tokyo-tech-campus

    Tokyo Tech is the top national university for science and technology in Japan with a history spanning more than 130 years. Of the approximately 10,000 students at the Ookayama, Suzukakedai, and Tamachi Campuses, half are in their bachelor’s degree program while the other half are in master’s and doctoral degree programs. International students number 1,200. There are 1,200 faculty and 600 administrative and technical staff members.

    In the 21st century, the role of science and technology universities has become increasingly important. Tokyo Tech continues to develop global leaders in the fields of science and technology, and contributes to the betterment of society through its research, focusing on solutions to global issues. The Institute’s long-term goal is to become the world’s leading science and technology university.

     
  • richardmitnick 8:08 am on April 11, 2018 Permalink | Reply
    Tags: Antihydrogen physics, , Applied Research & Technology, , ,   

    From UC Berkeley: “An Improved Method for Antihydrogen Spectroscopy” Berkeley Physics 

    UC Berkeley

    UC Berkeley

    April 4, 2018

    1
    Professor Jonathan Wurtele, undergraduate students Helia Kamal, Nate Belmore, Carlos Sierra, Stefania Balasiu, Cheyenne Nelson, graduate student Celeste Carruth, and Professor Joel Fajans.No image credit

    Berkeley physicists Joel Fajans and Jonathan Wurtele, along with their students and postdocs, have spent over a decade working on antihydrogen physics as part of the ALPHA Collaboration. The quest for precision antihydrogen spectroscopy was realized in a new paper that just appeared in Nature (Characterization of the 1S–2S transition in antihydrogen, Ahmadi et al.)

    Much of the effort of the Berkeley group has been to invent and develop new plasma physics techniques for synthesizing antihydrogen.

    A recent paper in Physical Review Letters, part of the thesis work of Celeste Carruth, reports an improved method for controlling plasma density and temperature, which in turn enabled a factor-of-ten increase in trapping rates. These increased trapping rates enabled reduced statistical and systematic errors that previously limited ALPHA measurements.

    The future is very promising. Improvements to the infrastructure for antiproton generation at CERN will provide on-demand antiprotons after the upcoming two-year CERN accelerator shutdown.

    Further improvements in antihydrogen synthesis may result from very successful plasma cavity cooling experiments by graduate student Eric Hunter. The work, interesting in their own right as a study of coupled nonlinear oscillators, appeared in Physics of Plasmas (Low magnetic field cooling of lepton plasmas via cyclotron-cavity resonance, E. Hunter et al.)

    The research has benefited from nearly two-dozen undergraduate students who have spent a summer at CERN working on ALPHA and worked here on the related plasma physics.

    CERN ALPHA Antimatter Factory

    See the full article here .

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    Founded in the wake of the gold rush by leaders of the newly established 31st state, the University of California’s flagship campus at Berkeley has become one of the preeminent universities in the world. Its early guiding lights, charged with providing education (both “practical” and “classical”) for the state’s people, gradually established a distinguished faculty (with 22 Nobel laureates to date), a stellar research library, and more than 350 academic programs.

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  • richardmitnick 7:46 am on April 11, 2018 Permalink | Reply
    Tags: , Applied Research & Technology, , broken symmetry, , Why symmetry gets really interesting when it is broken   

    From aeon: “Why symmetry gets really interesting when it is broken” 

    1

    aeon

    4.10.18

    Anthony Phillips

    1
    Detail from Composition VII (The Three Graces) (1917), by Theo van Doesburg. Photo courtesy Wikipedia

    A hypothetical alien visitor, sent to observe all of human culture – art and architecture, music and medicine, storytelling and science – would quickly conclude that we as a species are obsessed with patterns. The formal gardens of 18th-century England, the folk tales of medieval Germany and the traditional woven fabrics of Mayan civilisation have little in common, but they each owe their aesthetic appeal to being composed of smaller, identical parts arranged into a harmonious whole.

    It’s no coincidence that our Universe is naturally full of symmetry. The mirror symmetry of a stately home reflects the external form of many creatures, from butterflies to humans. At a deeper level, the very laws of the Universe are a consequence of its symmetries. An easy-to-state but profound example in the groundbreaking work of the German mathematician Emmy Noether is that the conservation laws that are ubiquitous in physics are in fact manifestations of the symmetries of the Universe. Energy is conserved, for instance, because the laws of physics are the same now as they were a millennium ago; momentum is conserved because they are the same here as they are on Pluto. Symmetry thus has the unusual distinction that it is fundamental both to the way the world works and to the extent to which we are capable of understanding it.

    Symmetry is at the core of my own work as a materials physicist. When atoms aggregate to make a material, they naturally arrange themselves into symmetrically repeating patterns. More than this, when we want the resulting material to be useful for a particular purpose – say, if we’re designing a touch sensor or an element of computer memory – these patterns must have the right symmetry to produce these useful properties.

    There is a further twist. In both art and science, perfectly symmetrical patterns can be monotonous. Indeed, there’s a sense in which symmetry is the opposite of information. If I showed you one wing of a butterfly, you could easily sketch the other; if I showed you a single paling, you could draw the entire picket fence. Since the missing pieces can so easily be reconstructed, they carry no new information.

    If, by contrast, we want to represent or store new information, it follows that we need to find ways to break the symmetry in order to encode our data.

    If successive palings in the picket fence differed in some way – say, if each were painted either white or blue at random – then the symmetry (and your ability to draw the whole fence) would be lost. Replace white palings with zeroes and blue palings with ones, and we have a binary representation of a number, the basis of digital data storage and manipulation.

    In a physical computer, these ones and zeroes are represented not by white and blue palings but by electrically or magnetically polarised materials. A polarised material is no longer isotropic (that is, the same in every direction), but instead has an electric or magnetic field pointing in a particular direction. It’s therefore a physical example of broken symmetry.

    This might seem like a technical and obscure point, but in fact symmetry-breaking is as fundamental to the Universe, and to our view of it, as symmetry itself. Water is a uniform soup of molecules, where any particular point is on average the same as any other; but when it freezes into ice, it solidifies into a fixed pattern, in which different places are distinguishable. The difference is the same as between a painted wall and one covered in wallpaper. On the painted surface, every point is identical, but on the papered one, each point is the same as only a few others: the corresponding points in adjacent copies of the pattern. We therefore say that some of a particular kind of symmetry has been lost, something known as translational symmetry – where, for a given movement from one point to another, the object is the same.

    At the cosmological scale, the differences between the fundamental forces that govern the Universe, including gravity and electromagnetism, are believed to be the result of symmetry breaking in a mathematically analogous way. The search for a ‘Theory of Everything’ that would explain the effects of these forces together is, in a profound sense, an attempt to look at ice and imagine water: to understand the symmetrical soup of the early Universe by looking back at it from the broken, patterned version that prevails today.

    The concept of symmetry-breaking is not just an intrinsically beautiful idea; it is of substantial practical use. Returning to materials science, it turns out that the symmetry required to produce a particular functionality is almost always the right kind of broken symmetry. Consider the phenomenon of piezoelectricity, which underlies ‘smart footpaths’ that can harvest the energy from people’s footsteps. Piezoelectricity involves a material that responds to pressure by generating an electric field (or vice versa). It was first noted in 1880 by the brothers Pierre and Jacques Curie: work less well known than Pierre and Marie Curie’s Nobel Prize-winning investigations of radioactivity, but equally groundbreaking. Piezoelectric materials are now used in everyday applications including clocks, cameras and printers, as well as being the basis for more futuristic technologies.

    It turns out that a material cannot be piezoelectric if it’s too symmetrical at the atomic level. Think about compressing a rubber cube with a ballbearing at its exact centre: all of the material around it might shift inwards, but the ball would stay in the same spot. A small amount of initial asymmetry, though, can be magnified when pressure is applied. If the ballbearing is off-centre to start with, squashing the cube inwards might shift it further from the middle – a movement that, applied by analogy to piezoelectricity, can generate an electrical field. The same argument holds for a host of other material properties that depend on electrical or magnetic ordering, or both: to produce these unusual effects, a certain amount of asymmetry is necessary.

    How, in practice, do we achieve such asymmetry by design? There are two basic prerequisites. First, we must ensure that the symmetry we want to break is inherently unstable. Consider a ping-pong ball atop a Mexican sombrero. It is most symmetrical balancing right in the middle, but this position is very unstable. The ball will roll down into the brim in one direction or another, spontaneously breaking the symmetry.

    A real material, though, consists of billions upon billions of atomic ‘hats’; if the ball rolls in a different direction in each, there will be no overall effect. The second prerequisite, therefore, is that each hat – each atomic component – should strongly influence its neighbours. If each component distorts in the same direction as those nearby, then the broken symmetry will be carried through from the atomic to the macroscopic scale. Given these requirements, designing a material with just the right kinds of symmetry demands real ingenuity, combining insights from chemistry, physics and materials science.

    We can also be cunning in how to achieve a low-symmetry state. One recent line of research, including in my own work, is to approach the problem indirectly. Rather than setting out to achieve, say, electrical polarisation in a single step, we can combine two different sorts of symmetry-breaking. Under the right circumstances, the combination can result in a polar ordering at the atomic scale even if neither of the ingredients would have done so individually – a behaviour known as hybrid improper ferroelectricity.

    Like materials design, the act of telling stories is about breaking patterns. In fairy tales, we’re likely to come across three bears, three pigs or three sons; in modern times, an enduring joke-pattern involves three protagonists (think ‘an Englishman, an Irishman and a Scotsman walk into a bar’) while comedians, improvisers and scriptwriters speak of the ‘rule of three’. Why this obsession with the number three? The answer is simple: the first time, something happens; the second time, something similar happens, establishing a pattern; but the third time, something different happens, breaking the pattern. The first two of the king’s sons come to a sticky end, while the third slays the dragon, marries the princess, and lives happily ever after. There is nothing magical about the number three, but since a pattern has to have at least two elements, a series of three is the most efficient way of establishing a kind of symmetry in order to disrupt it.

    At a certain level of abstraction, in both science and art, symmetry-breaking creates the conceptual space for interesting things to happen. Patterns might be appealing but, from ancient sagas to modern technology, they are at their most interesting, useful and revealing when broken.

    This Idea was made possible through the support of a grant from Templeton Religion Trust to Aeon. The opinions expressed in this publication are those of the author(s) and do not necessarily reflect the views of Templeton Religion Trust.

    See the full article here .

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    Since 2012, Aeon has established itself as a unique digital magazine, publishing some of the most profound and provocative thinking on the web. We ask the big questions and find the freshest, most original answers, provided by leading thinkers on science, philosophy, society and the arts.

    Aeon has three channels, and all are completely free to enjoy:

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    Through our Partnership program, we publish pieces from university research groups, university presses and other selected cultural organisations.

    Aeon was founded in London by Paul and Brigid Hains. It now has offices in London, Melbourne and New York. We are a not-for-profit, registered charity operated by Aeon Media Group Ltd. Aeon is endorsed as a Deductible Gift Recipient (DGR) organisation in Australia and, through its affiliate Aeon America, registered as a 501(c)(3) charity in the US.

    We are committed to big ideas, serious enquiry and a humane worldview. That’s it.

     
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