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  • richardmitnick 10:34 am on January 8, 2019 Permalink | Reply
    Tags: , Nanotechnology, Quantum scientists demonstrate world-first 3D atomic-scale quantum chip architecture, Single atom technology can be adapted to building 3D silicon quantum chips,   

    From University of New South Wales: “Quantum scientists demonstrate world-first 3D atomic-scale quantum chip architecture” 

    U NSW bloc

    From University of New South Wales

    08 Jan 2019
    Isabelle Dubach

    UNSW scientists have shown that their pioneering single atom technology can be adapted to building 3D silicon quantum chips – with precise interlayer alignment and highly accurate measurement of spin states. The 3D architecture is considered a major step in the development of a blueprint to build a large-scale quantum computer.

    1
    Study authors Dr Joris Keizer and Professor Michelle Simmons

    UNSW researchers at the Centre of Excellence for Quantum Computation and Communication Technology (CQC2T) have shown for the first time that they can build atomic precision qubits in a 3D device – another major step towards a universal quantum computer.

    The researchers, led by 2018 Australian of the Year and Director of CQC2T Professor Michelle Simmons, have demonstrated that they can extend their atomic qubit fabrication technique to multiple layers of a silicon crystal – achieving a critical component of the 3D chip architecture that they introduced to the world in 2015. This new research is published today in Nature Nanotechnology.

    The group is the first to demonstrate the feasibility of an architecture that uses atomic-scale qubits aligned to control lines – which are essentially very narrow wires – inside a 3D design.

    What’s more, team members were able to align the different layers in their 3D device with nanometer precision – and showed they could read out qubit states with what’s called ‘single shot’, i.e. within one single measurement, with very high fidelity.

    “This 3D device architecture is a significant advancement for atomic qubits in silicon,” says Professor Simmons.

    “To be able to constantly correct for errors in quantum calculations – an important milestone in our field – you have to be able to control many qubits in parallel.

    “The only way to do this is to use a 3D architecture, so in 2015 we developed and patented a vertical crisscross architecture. However, there were still a series of challenges related to the fabrication of this multi-layered device. With this result we have now shown that engineering our approach in 3D is possible in the way we envisioned it a few years ago.”

    In this paper, the team has demonstrated how to build a second control plane or layer on top of the first layer of qubits.

    “It’s a highly complicated process, but in very simple terms, we built the first plane, and then optimised a technique to grow the second layer without impacting the structures in first layer,” explains CQC2T researcher and co-author, Dr Joris Keizer.

    “In the past, critics would say that that’s not possible because the surface of the second layer gets very rough, and you wouldn’t be able to use our precision technique anymore – however, in this paper, we have shown that we can do it, contrary to expectations.”

    The team members also demonstrated that they can then align these multiple layers with nanometer precision.

    “If you write something on the first silicon layer and then put a silicon layer on top, you still need to identify your location to align components on both layers. We have shown a technique that can achieve alignment within under five nanometers, which is quite extraordinary,” Dr Keizer says.

    Lastly, the researchers were able to measure the qubit output of the 3D device single shot – i.e. with a single, accurate measurement, rather than having to rely on averaging out millions of experiments.

    “This will further help us scale up faster,” Dr Keizer explains.

    Towards commercialisation

    Professor Simmons says that this research is a milestone in the field.

    “We are working systematically towards a large-scale architecture that will lead us to the eventual commercialisation of the technology.

    “This is an important development in the field of quantum computing, but it’s also quite exciting for SQC,” says Professor Simmons, who is also the founder and a director of SQC.

    Since May 2017, Australia’s first quantum computing company, Silicon Quantum Computing Pty Limited (SQC), has been working to create and commercialise a quantum computer based on a suite of intellectual property developed at CQC2T and its own proprietary intellectual property.

    “While we are still at least a decade away from a large-scale quantum computer, the work of CQC2T remains at the forefront of innovation in this space. Concrete results such as these reaffirm our strong position internationally,” she concludes.

    See the full article here .


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  • richardmitnick 1:40 pm on January 3, 2019 Permalink | Reply
    Tags: "Controllable fast, A fundamental characteristic of electrons is their spin which points either up or down. A skyrmion is a circular cluster of electrons whose spins are opposite to the orientation of surrounding electro, , Dzyaloshinskii-Moriya interaction (DMI), Ferromagnets, , Nanotechnology, , , tiny magnetic bits"   

    From MIT News: “Controllable fast, tiny magnetic bits” 

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    MIT Widget

    From MIT News

    January 3, 2019
    Denis Paiste

    MIT researchers show how to make and drive nanoscale magnetic quasi-particles known as skyrmions for spintronic memory devices.

    1
    Work by researchers in the group of MIT materials science and engineering Professor Geoffrey Beach and colleagues in California, Germany, Switzerland and Korea, was featured on the covers of Nature Nanotechnology and Advanced Materials. Cover images reproduced with permission of the publishers.

    2
    Lucas Caretta (left) and Ivan Lemesh, graduate students in the lab of MIT professor of materials science and engineering Geoffrey Beach, each had a cover article in a peer-reviewed journal article in December. Their work is pioneering new directions for spintronic devices based on quasi-particles known as skyrmions. Photo: Denis Paiste/Materials Research Laboratory.

    For many modern technical applications, such as superconducting wires for magnetic resonance imaging, engineers want as much as possible to get rid of electrical resistance and its accompanying production of heat.

    It turns out, however, that a bit of heat production from resistance is a desirable characteristic in metallic thin films for spintronic applications such as solid-state computer memory. Similarly, while defects are often undesirable in materials science, they can be used to control creation of magnetic quasi-particles known as skyrmions.

    In separate papers published this month in the journals Nature Nanotechnology and Advanced Materials, researchers in the group of MIT Professor Geoffrey S.D. Beach and colleagues in California, Germany, Switzerland, and Korea, showed that they can generate stable and fast moving skyrmions in specially formulated layered materials at room temperature, setting world records for size and speed. Each paper was featured on the cover of its respective journal.

    For the research published in Advanced Materials [link is above], the researchers created a wire that stacks 15 repeating layers of a specially fabricated metal alloy made up of platinum, which is a heavy metal, cobalt-iron-boron, which is a magnetic material, and magnesium-oxygen. In these layered materials, the interface between the platinum metal layer and cobalt-iron-boron creates an environment in which skyrmions can be formed by applying an external magnetic field perpendicular to the film and electric current pulses that travel along the length of the wire.

    Notably, under a 20 milliTesla field, a measure of the magnetic field strength, the wire forms skyrmions at room temperature. At temperatures above 349 kelvins (168 degrees Fahrenheit), the skyrmions form without an external magnetic field, an effect caused by the material heating up, and the skyrmions remain stable even after the material is cooled back to room temperature. Previously, results like this had been seen only at low temperature and with large applied magnetic fields, Beach says.

    Predictable structure

    “After developing a number of theoretical tools, we now can not only predict the internal skyrmion structure and size, but we also can do a reverse engineering problem, we can say, for instance, we want to have a skyrmion of that size, and we’ll be able to generate the multi-layer, or the material, parameters, that would lead to the size of that skyrmion,” says Ivan Lemesh, first author of the Advanced Materials paper and a graduate student in materials science and engineering at MIT. Co-authors include senior author Beach and 17 others.

    A fundamental characteristic of electrons is their spin, which points either up or down. A skyrmion is a circular cluster of electrons whose spins are opposite to the orientation of surrounding electrons, and the skyrmions maintain a clockwise or counter-clockwise direction.

    “However, on top of that, we have also discovered that skyrmions in magnetic multilayers develop a complex through-thickness dependent twisted nature,” Lemesh said during a presentation on his work at the Materials Research Society (MRS) fall meeting in Boston on Nov. 30. Those findings were published in a separate theoretical study in Physical Review B in September.

    The current research shows that while this twisted structure of skyrmions has a minor impact on the ability to calculate the average size of the skyrmion, it significantly affects their current-induced behavior.

    Fundamental limits

    For the paper in Nature Nanotechnology [link is above], the researchers studied a different magnetic material, layering platinum with a magnetic layer of a gadolinium cobalt alloy, and tantalum oxide. In this material, the researchers showed they could produce skyrmions as small as 10 nanometers and established that they could move at a fast speed in the material.

    “What we discovered in this paper is that ferromagnets have fundamental limits for the size of the quasi-particle you can make and how fast you can drive them using currents,” says first author Lucas Caretta, a graduate student in materials science and engineering.

    In a ferromagnet, such as cobalt-iron-boron, neighboring spins are aligned parallel to one another and develop a strong directional magnetic moment. To overcome the fundamental limits of ferromagnets, the researchers turned to gadolinium-cobalt, which is a ferrimagnet, in which neighboring spins alternate up and down so they can cancel each other out and result in an overall zero magnetic moment.

    “One can engineer a ferrimagnet such that the net magnetization is zero, allowing ultrasmall spin textures, or tune it such that the net angular momentum is zero, enabling ultrafast spin textures. These properties can be engineered by material composition or temperature,” Caretta explains.

    In 2017, researchers in Beach’s group and their collaborators demonstrated experimentally that they could create these quasi-particles at will in specific locations by introducing a particular kind of defect in the magnetic layer.

    “You can change the properties of a material by using different local techniques such as ion bombardment, for instance, and by doing that you change its magnetic properties,” Lemesh says, “and then if you inject a current into the wire, the skyrmion will be born in that location.”

    Adds Caretta: “It was originally discovered with natural defects in the material, then they became engineered defects through the geometry of the wire.”

    They used this method to create skyrmions in the new Nature Nanotechnology [link is above] paper.

    The researchers made images of the skyrmions in the cobalt-gadolinium mixture at room temperature at synchrotron centers in Germany, using X-ray holography. Felix Büttner, a postdoc in the Beach lab, was one of the developers of this X-ray holography technique. “It’s one of the only techniques that can allow for such highly resolved images where you make out skyrmions of this size,” Caretta says.

    These skyrmions are as small as 10 nanometers, which is the current world record for room temperature skyrmions. The researchers demonstrated current driven domain wall motion of 1.3 kilometers per second, using a mechanism that can also be used to move skyrmions, which also sets a new world record.

    Except for the synchrotron work, all the research was done at MIT. “We grow the materials, do the fabrication and characterize the materials here at MIT,” Caretta says.

    Magnetic modeling

    These skyrmions are one type of spin configuration of electron spins in these materials, while domain walls are another. Domain walls are the boundary between domains of opposing spin orientation. In the field of spintronics, these configurations are known as solitons, or spin textures. Since skyrmions are a fundamental property of materials, mathematical characterization of their energy of formation and motion involves a complex set of equations incorporating their circular size, spin angular momentum, orbital angular momentum, electronic charge, magnetic strength, layer thickness, and several special physics terms that capture the energy of interactions between neighboring spins and neighboring layers, such as the exchange interaction.

    One of these interactions, which is called the Dzyaloshinskii-Moriya interaction (DMI), is of special significance to forming skyrmions and arises from the interplay between electrons in the platinum layer and the magnetic layer. In the Dzyaloshinskii-Moriya interaction, spins align perpendicular to each other, which stabilizes the skyrmion, Lemesh says. The DMI interaction allows for these skyrmions to be topological, giving rise to fascinating physics phenomena, making them stable, and allowing for them to be moved with a current.

    “The platinum itself is what provides what’s called a spin current which is what drives the spin textures into motion,” Caretta says. “The spin current provides a torque on the magnetization of the ferro or ferrimagnet adjacent to it, and this torque is what ultimately causes the motion of the spin texture. We’re basically using simple materials to realize complicated phenomena at interfaces.”

    In both papers, the researchers performed a mix of micromagnetic and atomistic spin calculations to determine the energy required to form skyrmions and to move them.

    “It turns out that by changing the fraction of a magnetic layer, you can change the average magnetic properties of the whole system, so now we don’t need to go to a different material to generate other properties,” Lemesh says. “You can just dilute the magnetic layer with a spacer layer of different thickness, and you will wind up with different magnetic properties, and that gives you an infinite number of opportunities to fabricate your system.”

    Precise control

    “Precise control of creating magnetic skyrmions is a central topic of the field,” says Jiadong Zang, an assistant professor of physics at the University of New Hampshire, who was not involved in this research, regarding the Advanced Materials paper. “This work has presented a new way of generating zero field skyrmions via current pulse. This is definitely a solid step towards skyrmion manipulations in nanosecond regime.”

    Commenting on the Nature Nanotechnology report, Christopher Marrows, a professor of condensed matter physics at the University of Leeds in the United Kingdom says: “The fact that the skyrmions are so small but can be stabilized at room temperature makes it very significant.”

    Marrows, who also was not involved in this research, noted that the Beach group had predicted room temperature skyrmions in a Scientific Reports paper earlier this year and said the new results are work of the highest quality. “But they made the prediction and real life does not always live up to theoretical expectations, so they deserve all the credit for this breakthrough,” Marrows says.

    Zang, commenting on the Nature Nanotechnology paper, adds: “A bottleneck of skyrmion study is to reach a size of smaller than 20 nanometers [the size of state-of-art memory unit], and drive its motion with speed beyond one kilometer per second. Both challenges have been tackled in this seminal work.

    “A key innovation is to use ferrimagnet, instead of commonly used ferromagnet, to host skyrmions,” Zang says. “This work greatly stimulates the design of skyrmion-based memory and logic devices. This is definitely a star paper in the skyrmion field.”

    Racetrack systems

    Solid-state devices built on these skyrmions could someday replace current magnetic storage hard drives. Streams of magnetic skyrmions can act as bits for computer applications. “In these materials, we can readily pattern magnetic tracks,” Beach said during a presentation at MRS.

    These new findings could be applied to racetrack memory devices, which were developed by Stuart Parkin at IBM. A key to engineering these materials for use in racetrack devices is engineering deliberate defects into the material where skyrmions can form, because skyrmions form where there are defects in the material.

    “One can engineer by putting notches in this type of system,” said Beach, who also is co-director of the Materials Research Laboratory (MRL) at MIT. A current pulse injected into the material forms the skyrmions at a notch. “The same current pulse can be used to write and delete,” he said. These skyrmions form extremely quickly, in less than a billionth of a second, Beach says.

    Says Caretta: “To be able to have a practical operating logic or memory racetrack device, you have to write the bit, so that’s what we talk about in creating the magnetic quasi particle, and you have to make sure that the written bit is very small and you have to translate that bit through the material at a very fast rate,” Caretta says.

    Marrows, the Leeds professor, adds: “Applications in skyrmion-based spintronics, will benefit, although again it’s a bit early to say for sure what will be the winners among the various proposals, which include memories, logic devices, oscillators and neuromorphic devices,”

    A remaining challenge is the best way to read these skyrmion bits. Work in the Beach group is continuing in this area, Lemesh says, noting that the current challenge is to discover a way to detect these skyrmions electrically in order to use them in computers or phones.

    “Yea, so you don’t have to take your phone to a synchrotron to read a bit,” Caretta says. “As a result of some of the work done on ferrimagnets and similar systems called anti-ferromagnets, I think the majority of the field will actually start to shift toward these types of materials because of the huge promise that they hold.”

    See the full article here .


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  • richardmitnick 12:44 pm on January 3, 2019 Permalink | Reply
    Tags: , , , Chemists create new quasicrystal material from nanoparticle building blocks, Nanotechnology   

    From Brown University: “Chemists create new quasicrystal material from nanoparticle building blocks” 

    Brown University
    From Brown University

    December 20, 2018

    Kevin Stacey
    kevin_stacey@brown.edu
    401-863-3766

    1
    Quasicrystal lattice, Researchers have shown that special nanoparticle building blocks can assemble themselves into a quasicrystalline lattice, an ordered structure with no discernible repeating pattern and exotic symmetries. Chen Lab / Brown University

    2
    Powerful pyramids, Ou Chen, assistant professor of chemistry, holds a mock-up of the tetrahedral quantum dot building blocks used to create macro-scale superstructures.

    Brown University researchers have discovered a new type of quasicrystal, a class of materials whose existence was thought to be impossible until the 1980s.

    The strange class of materials known as quasicrystals has a new member. In a paper published on Thursday, Dec. 20, in Science, researchers from Brown University describe a quasicrystalline superlattice that self-assembles from a single type of nanoparticle building blocks.

    This is the first definitive observation of a quasicrystalline superlattice formed from a single component, the researchers say. The discovery provides new insight into how these strange crystal-like structures can emerge.

    “Single-component quasicrystal lattices have been predicted mathematically and in computer simulations, but hadn’t been demonstrated before this,” said Ou Chen, an assistant professor of chemistry at Brown and the paper’s senior author. “It’s a fundamentally new type of quasicrystal, and we’ve been able to figure out the rules for making it, which will be useful in the continued study of quasicrystal structures.”

    Quasicrystal materials were first discovered in the 1980s by the chemist Dan Shechtman, who in 2011 was awarded the Nobel Prize for the discovery. Unlike crystals, which consist of ordered patterns that repeat, quasicrystals are ordered but their patterns don’t repeat. Quasicrystals also have symmetries that aren’t possible in traditional crystals. Normal crystals, for example, can have three-fold symmetries that emerge from repeating triangles or four-fold symmetry from repeating cubes. Two- and six-fold symmetries are also possible. But quasicrystals can have exotic five-, 10- or 12-fold symmetries, all of which are “forbidden” in normal crystals.

    The first quasicrystalline materials discovered were metal alloys, usually aluminum with one or more other metals. So far, these materials have found use as non-stick coatings for frying pans and anti-corrosive coatings for surgical equipment. But there’s been much interest in making new types of quasicrystal materials — including materials made from self-assembling nanoparticles.

    Chen and his colleagues hadn’t originally set out to research quasicrystals. Much of Chen’s work has been about bridging the gap between the nanoscale and macroscale worlds by building superstructures out of nanoparticle building blocks. About two years ago, he designed a new type of nanoparticle building block — a tetrahedral (pyramid-shaped) quantum dot. Whereas most research on building structures from nanoparticles has been done with spherical particles, Chen’s tetrahedra can pack more tightly and potentially form more complex and robust structures.

    Another key feature of Chen’s particles is that they’re anisotropic, meaning they have different properties depending upon their orientation relative to each other. One face of each pyramid particle has a different ligand (a bonding agent) than all other faces. Faces with like ligands tend to bond with each other when the particles assemble themselves into larger structures. That directed bonding makes for more interesting and complex structures compared with particles lacking anisotropy.

    In research published recently in the journal Nature, Chen and his team demonstrated one of the most complex superstructures created to date from nanoparticle building blocks. In that work, the superstructures were assembled while the particles interacted with a solid substrate. For this latest work, Chen and his colleagues wanted to see what kind of structures the particles would make when assembled on top of a liquid surface, which gives the particles more degrees of freedom when assembling themselves.

    The team was shocked to find that the resulting structure was actually a quasicrystalline lattice.

    “When I realized the pattern I was seeing was a quasicrystal, I emailed Ou and said ‘I think I’ve found something super-great,’” said Yasutaka Nagaoka, a postdoctoral scholar in Chen’s lab and the lead author of the new paper. “It was really exciting.”

    Using transmission electron microscopy, the researchers showed the particles assembled into discrete decagons (10-sided polygons), which stitched themselves together to form a quasicrystal lattice with 10-fold rotational symmetry. That 10-fold symmetry, forbidden in regular crystals, was a telltale sign of a quasicrystalline structure.

    The researchers were also able to divine the “rules” by which their structure formed. While decagons are the primary units of the structure, they are not — and cannot be — the only units in the structure. Forming a quasicrystal is a little like tiling a floor. The tiles have to fit together in a way that covers the entire floor without leaving any gaps. That can’t be done using only decagons because there’s no way to fit them together that doesn’t leave gaps. Other shapes are needed to fill the holes.

    The same goes for this new quasicrystal structure — they require secondary “tiles” that can fill the gaps between decagons. The researchers found that what enabled their structure to work is that the decagons have flexible edges. When necessary, one or more of their points could be flattened out. By doing that, they could morph into polygons with nine, eight, seven, six or five sides — whatever was required to fill the space between decagons.

    3
    The researchers showed how the nanoparticle decagons flexed their edges to in order to fit together in a quasicrystalline lattice.

    “These decagons are in this confined space that they have to share peacefully,” Chen said. “So they do it by making their edges flexible when they need to.”

    From that observation, the researchers were able to develop a new rule for forming quasicrystals that they call the “flexible polygon tiling rule.” That rule, Chen says, will be useful in continued study of the relatively new area of quasicrystals.

    “We think this work can inform research in material science, chemistry, mathematics and even art and design,” Chen said.

    Nagaoka’s and Chen’s co-authors on the paper were Hua Zhu and Dennis Eggert.

    See the full article here .

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  • richardmitnick 11:04 am on January 2, 2019 Permalink | Reply
    Tags: , , , Nanotechnology, Physicists record “lifetime” of graphene qubits, , ,   

    From MIT News: “Physicists record ‘lifetime’ of graphene qubits” 

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    From MIT News

    December 31, 2018
    Rob Matheson

    1
    Researchers from MIT and elsewhere have recorded the “temporal coherence” of a graphene qubit — how long it maintains a special state that lets it represent two logical states simultaneously — marking a critical step forward for practical quantum computing. Stock image

    First measurement of its kind could provide stepping stone to practical quantum computing.

    Researchers from MIT and elsewhere have recorded, for the first time, the “temporal coherence” of a graphene qubit — meaning how long it can maintain a special state that allows it to represent two logical states simultaneously. The demonstration, which used a new kind of graphene-based qubit, represents a critical step forward for practical quantum computing, the researchers say.

    Superconducting quantum bits (simply, qubits) are artificial atoms that use various methods to produce bits of quantum information, the fundamental component of quantum computers. Similar to traditional binary circuits in computers, qubits can maintain one of two states corresponding to the classic binary bits, a 0 or 1. But these qubits can also be a superposition of both states simultaneously, which could allow quantum computers to solve complex problems that are practically impossible for traditional computers.

    The amount of time that these qubits stay in this superposition state is referred to as their “coherence time.” The longer the coherence time, the greater the ability for the qubit to compute complex problems.

    Recently, researchers have been incorporating graphene-based materials into superconducting quantum computing devices, which promise faster, more efficient computing, among other perks. Until now, however, there’s been no recorded coherence for these advanced qubits, so there’s no knowing if they’re feasible for practical quantum computing.

    In a paper published today in Nature Nanotechnology, the researchers demonstrate, for the first time, a coherent qubit made from graphene and exotic materials. These materials enable the qubit to change states through voltage, much like transistors in today’s traditional computer chips — and unlike most other types of superconducting qubits. Moreover, the researchers put a number to that coherence, clocking it at 55 nanoseconds, before the qubit returns to its ground state.

    The work combined expertise from co-authors William D. Oliver, a physics professor of the practice and Lincoln Laboratory Fellow whose work focuses on quantum computing systems, and Pablo Jarillo-Herrero, the Cecil and Ida Green Professor of Physics at MIT who researches innovations in graphene.

    “Our motivation is to use the unique properties of graphene to improve the performance of superconducting qubits,” says first author Joel I-Jan Wang, a postdoc in Oliver’s group in the Research Laboratory of Electronics (RLE) at MIT. “In this work, we show for the first time that a superconducting qubit made from graphene is temporally quantum coherent, a key requisite for building more sophisticated quantum circuits. Ours is the first device to show a measurable coherence time — a primary metric of a qubit — that’s long enough for humans to control.”

    There are 14 other co-authors, including Daniel Rodan-Legrain, a graduate student in Jarillo-Herrero’s group who contributed equally to the work with Wang; MIT researchers from RLE, the Department of Physics, the Department of Electrical Engineering and Computer Science, and Lincoln Laboratory; and researchers from the Laboratory of Irradiated Solids at the École Polytechnique and the Advanced Materials Laboratory of the National Institute for Materials Science.

    A pristine graphene sandwich

    Superconducting qubits rely on a structure known as a “Josephson junction,” where an insulator (usually an oxide) is sandwiched between two superconducting materials (usually aluminum). In traditional tunable qubit designs, a current loop creates a small magnetic field that causes electrons to hop back and forth between the superconducting materials, causing the qubit to switch states.

    But this flowing current consumes a lot of energy and causes other issues. Recently, a few research groups have replaced the insulator with graphene, an atom-thick layer of carbon that’s inexpensive to mass produce and has unique properties that might enable faster, more efficient computation.

    To fabricate their qubit, the researchers turned to a class of materials, called van der Waals materials — atomic-thin materials that can be stacked like Legos on top of one another, with little to no resistance or damage. These materials can be stacked in specific ways to create various electronic systems. Despite their near-flawless surface quality, only a few research groups have ever applied van der Waals materials to quantum circuits, and none have previously been shown to exhibit temporal coherence.

    For their Josephson junction, the researchers sandwiched a sheet of graphene in between the two layers of a van der Waals insulator called hexagonal boron nitride (hBN). Importantly, graphene takes on the superconductivity of the superconducting materials it touches. The selected van der Waals materials can be made to usher electrons around using voltage, instead of the traditional current-based magnetic field. Therefore, so can the graphene — and so can the entire qubit.

    When voltage gets applied to the qubit, electrons bounce back and forth between two superconducting leads connected by graphene, changing the qubit from ground (0) to excited or superposition state (1). The bottom hBN layer serves as a substrate to host the graphene. The top hBN layer encapsulates the graphene, protecting it from any contamination. Because the materials are so pristine, the traveling electrons never interact with defects. This represents the ideal “ballistic transport” for qubits, where a majority of electrons move from one superconducting lead to another without scattering with impurities, making a quick, precise change of states.

    How voltage helps

    The work can help tackle the qubit “scaling problem,” Wang says. Currently, only about 1,000 qubits can fit on a single chip. Having qubits controlled by voltage will be especially important as millions of qubits start being crammed on a single chip. “Without voltage control, you’ll also need thousands or millions of current loops too, and that takes up a lot of space and leads to energy dissipation,” he says.

    Additionally, voltage control means greater efficiency and a more localized, precise targeting of individual qubits on a chip, without “cross talk.” That happens when a little bit of the magnetic field created by the current interferes with a qubit it’s not targeting, causing computation problems.

    For now, the researchers’ qubit has a brief lifetime. For reference, conventional superconducting qubits that hold promise for practical application have documented coherence times of a few tens of microseconds, a few hundred times greater than the researchers’ qubit.

    But the researchers are already addressing several issues that cause this short lifetime, most of which require structural modifications. They’re also using their new coherence-probing method to further investigate how electrons move ballistically around the qubits, with aims of extending the coherence of qubits in general.

    See the full article here .


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  • richardmitnick 2:31 pm on December 15, 2018 Permalink | Reply
    Tags: Expansion microscopy, Implosion fabrication, , Nanotechnology, Team invents method to shrink objects to the nanoscale, The system produces 3-D structures one thousandth the size of the originals   

    From MIT News: “Team invents method to shrink objects to the nanoscale” 

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    From MIT News

    December 13, 2018
    Anne Trafton

    1
    MIT engineers have devised a way to create 3-D nanoscale objects by patterning a larger structure with a laser and then shrinking it. This image shows a complex structure prior to shrinking. Image: Daniel Oran

    2
    The MIT technique, known as “implosion fabrication,” can be used to create nearly any shape imaginable. Image: Daniel Oran

    It’s not quite the Ant-Man suit, but the system produces 3-D structures one thousandth the size of the originals.

    MIT researchers have invented a way to fabricate nanoscale 3-D objects of nearly any shape. They can also pattern the objects with a variety of useful materials, including metals, quantum dots, and DNA.

    “It’s a way of putting nearly any kind of material into a 3-D pattern with nanoscale precision,” says Edward Boyden, the Y. Eva Tan Professor in Neurotechnology and an associate professor of biological engineering and of brain and cognitive sciences at MIT.

    Using the new technique, the researchers can create any shape and structure they want by patterning a polymer scaffold with a laser. After attaching other useful materials to the scaffold, they shrink it, generating structures one thousandth the volume of the original.

    These tiny structures could have applications in many fields, from optics to medicine to robotics, the researchers say. The technique uses equipment that many biology and materials science labs already have, making it widely accessible for researchers who want to try it.

    Boyden, who is also a member of MIT’s Media Lab, McGovern Institute for Brain Research, and Koch Institute for Integrative Cancer Research, is one of the senior authors of the paper, which appears in the Dec. 13 issue of Science. The other senior author is Adam Marblestone, a Media Lab research affiliate, and the paper’s lead authors are graduate students Daniel Oran and Samuel Rodriques.

    Implosion fabrication

    Existing techniques for creating nanostructures are limited in what they can accomplish. Etching patterns onto a surface with light can produce 2-D nanostructures but doesn’t work for 3-D structures. It is possible to make 3-D nanostructures by gradually adding layers on top of each other, but this process is slow and challenging. And, while methods exist that can directly 3-D print nanoscale objects, they are restricted to specialized materials like polymers and plastics, which lack the functional properties necessary for many applications. Furthermore, they can only generate self-supporting structures. (The technique can yield a solid pyramid, for example, but not a linked chain or a hollow sphere.)

    To overcome these limitations, Boyden and his students decided to adapt a technique that his lab developed a few years ago for high-resolution imaging of brain tissue. This technique, known as expansion microscopy, involves embedding tissue into a hydrogel and then expanding it, allowing for high resolution imaging with a regular microscope. Hundreds of research groups in biology and medicine are now using expansion microscopy, since it enables 3-D visualization of cells and tissues with ordinary hardware.

    By reversing this process, the researchers found that they could create large-scale objects embedded in expanded hydrogels and then shrink them to the nanoscale, an approach that they call “implosion fabrication.”

    As they did for expansion microscopy, the researchers used a very absorbent material made of polyacrylate, commonly found in diapers, as the scaffold for their nanofabrication process. The scaffold is bathed in a solution that contains molecules of fluorescein, which attach to the scaffold when they are activated by laser light.

    Using two-photon microscopy, which allows for precise targeting of points deep within a structure, the researchers attach fluorescein molecules to specific locations within the gel. The fluorescein molecules act as anchors that can bind to other types of molecules that the researchers add.

    “You attach the anchors where you want with light, and later you can attach whatever you want to the anchors,” Boyden says. “It could be a quantum dot, it could be a piece of DNA, it could be a gold nanoparticle.”

    “It’s a bit like film photography — a latent image is formed by exposing a sensitive material in a gel to light. Then, you can develop that latent image into a real image by attaching another material, silver, afterwards. In this way implosion fabrication can create all sorts of structures, including gradients, unconnected structures, and multimaterial patterns,” Oran says.

    Once the desired molecules are attached in the right locations, the researchers shrink the entire structure by adding an acid. The acid blocks the negative charges in the polyacrylate gel so that they no longer repel each other, causing the gel to contract. Using this technique, the researchers can shrink the objects 10-fold in each dimension (for an overall 1,000-fold reduction in volume). This ability to shrink not only allows for increased resolution, but also makes it possible to assemble materials in a low-density scaffold. This enables easy access for modification, and later the material becomes a dense solid when it is shrunk.

    “People have been trying to invent better equipment to make smaller nanomaterials for years, but we realized that if you just use existing systems and embed your materials in this gel, you can shrink them down to the nanoscale, without distorting the patterns,” Rodriques says.

    Currently, the researchers can create objects that are around 1 cubic millimeter, patterned with a resolution of 50 nanometers. There is a tradeoff between size and resolution: If the researchers want to make larger objects, about 1 cubic centimeter, they can achieve a resolution of about 500 nanometers. However, that resolution could be improved with further refinement of the process, the researchers say.

    Better optics

    The MIT team is now exploring potential applications for this technology, and they anticipate that some of the earliest applications might be in optics — for example, making specialized lenses that could be used to study the fundamental properties of light. This technique might also allow for the fabrication of smaller, better lenses for applications such as cell phone cameras, microscopes, or endoscopes, the researchers say. Farther in the future, the researchers say that this approach could be used to build nanoscale electronics or robots.

    “There are all kinds of things you can do with this,” Boyden says. “Democratizing nanofabrication could open up frontiers we can’t yet imagine.”

    Many research labs are already stocked with the equipment required for this kind of fabrication. “With a laser you can already find in many biology labs, you can scan a pattern, then deposit metals, semiconductors, or DNA, and then shrink it down,” Boyden says.

    The research was funded by the Kavli Dream Team Program, the HHMI-Simons Faculty Scholars Program, the Open Philanthropy Project, John Doerr, the Office of Naval Research, the National Institutes of Health, the New York Stem Cell Foundation-Robertson Award, the U.S. Army Research Office, K. Lisa Yang and Y. Eva Tan, and the MIT Media Lab.

    See the full article here .


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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 5:53 pm on November 12, 2018 Permalink | Reply
    Tags: , , , MicroED-micro-electron diffraction, Nanotechnology, NMR-nuclear magnetic resonance, , , ,   

    From Caltech: “From Beaker to Solved 3-D Structure in Minutes” 

    Caltech Logo

    From Caltech

    11/12/2018

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

    1
    Graduate student Tyler Fulton prepares samples of small molecules in a lab at Caltech. Credit: Caltech

    2
    Close-up of a powder containing small molecules like those that gave rise to 3-D structures in the new study. (The copper piece is a sample holder used with microscopes.) Credit: Caltech/Stoltz Lab

    3
    Brian Stoltz and Tyler Fulton. Credit: Caltech

    UCLA/Caltech team uncovers a new and simple way to learn the structures of small molecules.

    In a new study that one scientist called jaw-dropping, a joint UCLA/Caltech team has shown that it is possible to obtain the structures of small molecules, such as certain hormones and medications, in as little as 30 minutes. That’s hours and even days less than was possible before.

    The team used a technique called micro-electron diffraction (MicroED), which had been used in the past to learn the 3-D structures of larger molecules, specifically proteins. In this new study, the researchers show that the technique can be applied to small molecules, and that the process requires much less preparation time than expected. Unlike related techniques—some of which involve growing crystals the size of salt grains—this method, as the new study demonstrates, can work with run-of-the-mill starting samples, sometimes even powders scraped from the side of a beaker.

    “We took the lowest-brow samples you can get and obtained the highest-quality structures in barely any time,” says Caltech professor of chemistry Brian Stoltz, who is a co-author on the new study, published in the journal ACS Central Science. “When I first saw the results, my jaw hit the floor.” Initially released on the pre-print server Chemrxiv in mid-October, the article has been viewed more than 35,000 times.

    The reason the method works so well on small-molecule samples is that while the samples may appear to be simple powders, they actually contain tiny crystals, each roughly a billion times smaller than a speck of dust. Researchers knew about these hidden microcrystals before, but did not realize they could readily reveal the crystals’ molecular structures using MicroED. “I don’t think people realized how common these microcrystals are in the powdery samples,” says Stoltz. “This is like science fiction. I didn’t think this would happen in my lifetime—that you could see structures from powders.”

    4
    This movie [animated in the full article] is an example of electron diffraction (MicroED) data collection, in which electrons are fired at a nanocrystal while being continuously rotated. Data from the movie are ultimately converted to a 3-D chemical structure. Credit: UCLA/Caltech

    The results have implications for chemists wishing to determine the structures of small molecules, which are defined as those weighing less than about 900 daltons. (A dalton is about the weight of a hydrogen atom.) These tiny compounds include certain chemicals found in nature, some biological substances like hormones, and a number of therapeutic drugs. Possible applications of the MicroED structure-finding methodology include drug discovery, crime lab analysis, medical testing, and more. For instance, Stoltz says, the method might be of use in testing for the latest performance-enhancing drugs in athletes, where only trace amounts of a chemical may be present.

    “The slowest step in making new molecules is determining the structure of the product. That may no longer be the case, as this technique promises to revolutionize organic chemistry,” says Robert Grubbs, Caltech’s Victor and Elizabeth Atkins Professor of Chemistry and a winner of the 2005 Nobel Prize in Chemistry, who was not involved in the research. “The last big break in structure determination before this was nuclear magnetic resonance spectroscopy, which was introduced by Jack Roberts at Caltech in the late ’60s.”

    Like other synthetic chemists, Stoltz and his team spend their time trying to figure out how to assemble chemicals in the lab from basic starting materials. Their lab focuses on such natural small molecules as the fungus-derived beta-lactam family of compounds, which are related to penicillins. To build these chemicals, they need to determine the structures of the molecules in their reactions—both the intermediate molecules and the final products—to see if they are on the right track.

    One technique for doing so is X-ray crystallography, in which a chemical sample is hit with X-rays that diffract off its atoms; the pattern of those diffracting X-rays reveals the 3-D structure of the targeted chemical. Often, this method is used to solve the structures of really big molecules, such as complex membrane proteins, but it can also be applied to small molecules. The challenge is that to perform this method a chemist must create good-sized chunks of crystal from a sample, which isn’t always easy. “I spent months once trying to get the right crystals for one of my samples,” says Stoltz.

    Another reliable method is NMR (nuclear magnetic resonance), which doesn’t require crystals but does require a relatively large amount of a sample, which can be hard to amass. Also, NMR provides only indirect structural information.

    Before now, MicroED—which is similar to X-ray crystallography but uses electrons instead of X-rays—was mainly used on crystallized proteins and not on small molecules. Co-author Tamir Gonen, an electron crystallography expert at UCLA who began developing the MicroED technique for proteins while at the Howard Hughes Medical Institute in Virginia, said that he only started thinking about using the method on small molecules after moving to UCLA and teaming up with Caltech.

    “Tamir had been using this technique on proteins, and just happened to mention that they can sometimes get it to work using only powdery samples of proteins,” says Hosea Nelson (PhD ’13), an assistant professor of chemistry and biochemistry at UCLA. “My mind was blown by this, that you didn’t have to grow crystals, and that’s around the time that the team started to realize that we could apply this method to a whole new class of molecules with wide-reaching implications for all types of chemistry.”

    The team tested several samples of varying qualities, without ever attempting to crystallize them, and were able to determine their structures thanks to the samples’ ample microcrystals. They succeeded in getting structures for ground-up samples of the brand-name drugs Tylenol and Advil, and they were able to identify distinct structures from a powdered mixture of four chemicals.

    The UCLA/Caltech team says it hopes this method will become routine in chemistry labs in the future.

    “In our labs, we have students and postdocs making totally new and unique molecular entities every day,” says Stoltz. “Now we have the power to rapidly figure out what they are. This is going to change synthetic chemistry.”

    The study was funded by the National Science Foundation, the National Institutes of Health, the Department of Energy, a Beckman Young Investigators award, a Searle Scholars award, a Pew Scholars award, the Packard Foundation, the Sloan Foundation, the Pew Charitable Trusts, and the Howard Hughes Medical Institute. Other co-authors include Christopher Jones,Michael Martynowycz, Johan Hattne, and Jose Rodriguez of UCLA; and Tyler Fulton of Caltech.

    See the full article here .


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

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  • richardmitnick 2:07 pm on November 12, 2018 Permalink | Reply
    Tags: A research team has adapted a powerful electron-based imaging technique to obtain an image of atomic-scale structure in a synthetic polymer., Before these high-resolution images the arrangement and variation of the different types of crystal structures was unknown, , Cryogenic electron microscopy, Images of individual atoms in polymers had only been realized in computer simulations and illustrations, , Nanotechnology, Peptoids are synthetically produced molecules that mimic biological molecules including chains of amino acids known as peptides, , Researchers achieved resolution of about 2 angstroms which is two-tenths of nanometer (billionth of a meter), Scientists Bring Polymers Into Atomic-Scale Focus, There are still mysteries about polymers at the atomic scale,   

    From Lawrence Berkeley National Lab and UC Berkeley: “Scientists Bring Polymers Into Atomic-Scale Focus” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    November 12, 2018
    Glenn Roberts Jr.
    geroberts@lbl.gov
    (510) 486-5582

    1
    This image shows a rendering (gray and pink) of the molecular structure of a peptoid polymer that was studied by a team led by Berkeley Lab and UC Berkeley. The successful imaging of a polymer’s atomic-scale structure could inform new designs for plastics, like those that form the water bottles shown in the background. (Credit: Berkeley Lab, Charles Rondeau/PublicDomainPictures.net)

    From water bottles and food containers to toys and tubing, many modern materials are made of plastics. And while we produce about 110 million tons per year of synthetic polymers like polyethylene and polypropylene worldwide for these plastic products, there are still mysteries about polymers at the atomic scale.

    Because of the difficulty in capturing images of these materials at tiny scales, images of individual atoms in polymers have only been realized in computer simulations and illustrations, for example.

    Now, a research team led by Nitash Balsara, a senior faculty scientist in the Materials Sciences Division at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and professor of chemical and biomolecular engineering at UC Berkeley, has adapted a powerful electron-based imaging technique to obtain an image of atomic-scale structure in a synthetic polymer. The team included researchers from Berkeley Lab and UC Berkeley.

    The research could ultimately inform polymer fabrication methods and lead to new designs for materials and devices that incorporate polymers.

    In their study, published in the American Chemical Society’s Macromolecules journal, the researchers detail the development of a cryogenic electron microscopy imaging technique, aided by computerized simulations and sorting techniques, that identified 35 arrangements of crystal structures in a peptoid polymer sample. Peptoids are synthetically produced molecules that mimic biological molecules, including chains of amino acids known as peptides.

    2
    The simulated atomic-scale structure (top) and the averaged atomic-scale imaging (bottom) of a peptoid polymer sample. The sale bar is 10 angstroms, or 1 billionth of a meter. (Credit: Berkeley Lab, UC Berkeley)

    The sample was robotically synthesized at Berkeley Lab’s Molecular Foundry, a DOE Office of Science User Facility for nanoscience research. Researchers formed sheets of crystallized polymers measuring about 5 nanometers (billionths of a meter) in thickness when dispersed in water.

    “We conducted our experiments on the most perfect polymer molecules we could make,” Balsara said – the peptoid samples in the study were extremely pure compared to typical synthetic polymers.

    The research team created tiny flakes of peptoid nanosheets, froze them to preserve their structure, and then imaged them using an electron beam. An inherent challenge in imaging materials with a soft structure, such as polymers, is that the beam used to capture images also damages the samples.

    The direct cryogenic electron microscopy images, obtained using very few electrons to minimize beam damage, are too blurry to reveal individual atoms. Researchers achieved resolution of about 2 angstroms, which is two-tenths of nanometer (billionth of a meter), or about double the diameter of a hydrogen atom.

    They achieved this by taking over 500,000 blurry images, sorting different motifs into different “bins,” and averaging the images in each bin. The sorting methods they used were based on algorithms developed by the structural biology community to image the atomic structure of proteins.

    “We took advantage of technology that the protein-imaging folks had developed and extended it to human-made, soft materials,” Balsara said. “Only when we sorted them and averaged them did that blurriness become clear.”

    Before these high-resolution images, Balsara said, the arrangement and variation of the different types of crystal structures was unknown.

    “We knew that there were many motifs, but they are all different from each other in ways we didn’t know,” he said. “In fact, even the dominant motif in the peptoid sheet was a surprise.”

    3
    Researchers developed a colorized map (right) to show the distribution of different types of crystal structures (left) that they found in the polymer peptoid sample. The scale bar in the map image is 50 nanometers, or 50 billionths of a meter. (Credit: Berkeley Lab, UC Berkeley)

    Balsara credited Ken Downing, a senior scientist in Berkeley Lab’s Molecular Biophysics and Integrated Bioimaging Division who passed away in August, and Xi Jiang, a project scientist in the Materials Sciences Division, for capturing the high-quality images that were central to the study and for developing the algorithms necessary to achieve atomic resolution in the polymer imaging.

    Their expertise in cryogenic electron microscopy was complemented by Ron Zuckermann’s ability to synthesize model peptoids, David Prendergast’s knowledge of molecular dynamics simulations needed to interpret the images, Andrew Minor’s expertise in imaging metals at the atomic scale, and Balsara’s experience in the field of polymer science.

    At the Molecular Foundry, Zuckermann directs the Biological Nanostructures facility, Prendergast directs the Theory facility, and Minor directs the National Center for Electron Microscopy and is also a professor of materials science and engineering at UC Berkeley. Much of the cryo-electron imaging was carried out at UC Berkeley’s Krios microscopy facility.

    Balsara said that his own research into using polymers for batteries and other electrochemical devices could benefit from the research, as seeing the position of polymer atoms could greatly aid in the design of materials for these devices.

    Atomic-scale images of polymers used in everyday life may need more sophisticated, automated filtering mechanisms that rely on machine learning, for example.

    “We should be able to determine the atomic-scale structure of a wide variety of synthetic polymers such as commercial polyethylene and polypropylene, leveraging rapid developments in areas such as artificial intelligence, using this approach,” Balsara said.

    Determining crystal structures can provide vital information for other applications, such as the development of drugs, as different crystal motifs could produce quite different binding properties and therapeutic effects, for example.

    The work was conducted within the Soft Matter Electron Microscopy Program at Berkeley Lab, which is supported by the U.S. Department of Energy’s Office of Science; and by the Bay Area Cryo-EM Consortium.

    See the full article here .

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    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

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

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  • richardmitnick 7:22 pm on November 9, 2018 Permalink | Reply
    Tags: , , , , , , , , , , , , Nanotechnology, , Understanding our own backyard will be key in interpreting data from far-flung exoplanets   

    From COSMOS Magazine: “The tech we’re going to need to detect ET” 

    Cosmos Magazine bloc

    From COSMOS Magazine

    09 November 2018
    Lauren Fuge

    1
    Searching for biosignatures rather than examples of life itself is considered a prime strategy in the hunt for ET. smartboy10/Getty Images

    Move over Mars rovers, new technologies to detect alien life are on the horizon.

    A group of scientists from around the world, led by astrochemistry expert Chaitanya Giri from the Tokyo Institute of Technology in Japan, have put their heads together to plan the next 20 years’ worth of life-detection technologies. The study is currently awaiting peer review, but is freely available on the pre-print site, ArXiv.

    For decades, astrobiologists have scoured the skies and the sands of other planets for hints of extraterrestrial life. Not only are these researchers trying to find ET, but they’re also aiming to learn about the origin and evolution of life on Earth, the chemical composition of organic extraterrestrial objects, what makes a planet or satellite habitable, and more.

    But the answers to such questions are preceded by long years of planning, development, problem-solving and strategising.

    Late in 2017, 20 scientists from Japan, India, France, Germany and the USA – each with a special area of expertise – came together at a workshop run by the Earth-Life Science Institute (ELSI) at Giri’s Tokyo campus. There, they discussed the current progress and enticing possibilities of life-detection technologies.

    In particular, the boffins debated which ones should be a priority for research and development for missions within the local solar system – in other words, which instruments will be most feasible to out onto a space probe and send off to Mars or Enceladus during the next couple of decades.

    Of course, the planets and moons in the solar system are an extremely limited sample of the number of potentially habitable worlds in the universe, but understanding our own backyard will be key in interpreting data from far-flung exoplanets.

    So, according to these astrobiology experts, what’s the future plan for alien detection?

    The first step of any space mission is to study the planet or satellite from afar to determine whether it is habitable. Luckily, an array of next-generation telescopes is currently being built, from the ultra-sensitive James Webb Space Telescope, slated for launch in 2021, to the gargantuan Extremely Large Telescope in Chile, which will turn its 39-metre eye to the sky in 2024. The authors point out that observatories such as these will vastly expand our theoretical knowledge of planet habitability.

    NASA/ESA/CSA Webb Telescope annotated

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

    Just because a world is deemed habitable doesn’t mean life will be found all over it, though. It may exist only in limited geographical niches. To reach these inaccessible sites, the paper argues that we will require “agile robotic probes that are robust, able to seamlessly communicate with orbiters and deep space communications networks, be operationally semi-autonomous, have high-performance energy supplies, and are sterilisable to avoid forward contamination”.

    But according to Elizabeth Tasker, associate professor at the Japan Aerospace Exploration Agency (JAXA), who was not involved in the study, getting there is only half the struggle.

    “In fact, it’s the most tractable half because we can picture the problems we will face,” she says.

    The second, more pressing issue is how to recognise life unlike anything we know on Earth.

    As Tasker explains: “We only have Earth life to compare to and this is the result of huge evolutionary history on a planet whose complex past is unlikely to be replicated closely. That’s a lot of baggage to separate out.”

    According to the paper, the way forward is to equip missions with a suite of life-detection instruments that don’t look for life as we know it, but are instead able to identify the kinds of features that make organisms function.

    The authors outline a huge variety of exciting technologies that could be used for this purpose, including spectroscopy techniques (to analyse potential biological materials), quantum tunnelling [Nature Nanotechnology
    ] (to find DNA, RNA, peptides, and other small molecules), and fluorescence microscopy [ https://www.hou.usra.edu/meetings/lpsc2014/pdf/2744.pdf ](to identify the presence of cell membranes).

    They also nominate different forms of gas chromatography (to spot amino acids and sugars formed by living organisms, plus checking to see if molecules are “homochiral” [Space Science Reviews] (a suspected biosignature) using microfluidic devices and microscopes.

    High-resolution, miniaturised mass spectrometers would also be helpful, characterising biopolymers, which are created by living organisms, and measuring the elemental composition of objects to aid isotopic dating.

    Giri and colleagues also stress that exciting developments in machine learning, artificial intelligence, and pattern recognition will be useful in determining whether chemical samples are biological in origin.

    Interestingly, researchers are also developing technologies that may allow the detection of life in more unconventional places. On Earth, for example, cryotubes were recently used [International Journal of Systematic and Evolutionary Microbiology] to discover several new species of bacteria in the upper atmosphere.

    The scientists also discuss how certain technologies – such as high-powered synchrotron radiation and magnetic field facilities – are not yet compact enough to fly to other planets, and so samples must continue to be brought back for analysis.

    Several sample-and-return missions are currently underway, including JAXA’s Martian Moons exploration mission to Phobos, Hayabusa-2 to asteroid Ryugu, and NASA’s OSIRIS-rex to asteroid Bennu. What we learn from handling the organic-rich extraterrestrial materials brought back from these trips will be invaluable.

    JAXA MMX spacecraft

    JAXA/Hayabusa 2 Credit: JAXA/Akihiro Ikeshita

    NASA OSIRIS-REx Spacecraft

    What we learn from handling the organic-rich extraterrestrial materials brought back from these trips will be invaluable.

    The predictions and recommendations put forward by Giri and colleagues are the first steps in getting these technologies discussed in panel reviews, included in decadal surveys, and eventually funded.

    They complement several similar efforts, including a report prepared by US National Academies of Science, Engineering and Medicine (NASEM), calling for an expansion of the range of possible ET indicators, and a US-led exploration of how the next generation of radio telescopes will be utilised by SETI.

    Perhaps most importantly, these papers all highlight the need for collaborative work between scientists across disciplines.

    “A successful detection of life will need astrophysicists and geologists to examine possible environments on other planets, engineers and physicists to design the missions and instruments that can collect data, and chemists and biologists to determine how to classify life,” JAXA’s Tasker says.

    “But maybe that is appropriate: finding out what life really is and where it can flourish is the story of everyone on Earth. It should take all of us to unravel.”

    See the full article here .


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  • richardmitnick 12:20 pm on October 10, 2018 Permalink | Reply
    Tags: , Nanotechnology, , Scientists forge ahead with electron microscopy to build quantum materials atom by atom,   

    From Oak Ridge National Laboratory: “Scientists forge ahead with electron microscopy to build quantum materials atom by atom” 

    i1

    From Oak Ridge National Laboratory

    October 9, 2018
    Sara Shoemaker, Communications
    shoemakerms@ornl.gov
    865.576.9219

    A novel technique that nudges single atoms to switch places within an atomically thin material could bring scientists another step closer to realizing theoretical physicist Richard Feynman’s vision of building tiny machines from the atom up.

    A significant push to develop materials that harness the quantum nature of atoms is driving the need for methods to build atomically precise electronics and sensors. Fabricating nanoscale devices atom by atom requires delicacy and precision, which has been demonstrated by a microscopy team at the Department of Energy’s Oak Ridge National Laboratory.

    They used a scanning transmission electron microscope, or STEM, at the lab’s Center for Nanophase Materials Sciences to introduce silicon atoms into a single-atom-thick sheet of graphene. As the electron beam scans across the material, its energy slightly disrupts the graphene’s molecular structure and creates room for a nearby silicon atom to swap places with a carbon atom.

    Custom-designed scanning transmission electron microscope at Cornell University by David Muller/Cornell University

    “We observed an electron beam-assisted chemical reaction induced at a single atom and chemical bond level, and each step has been captured by the microscope, which is rare,” said ORNL’s Ondrej Dyck, co-author of a study published in the journal Small that details the STEM demonstration.

    2
    Ondrej Dyck of Oak Ridge National Laboratory used a scanning transmission electron microscope to move single atoms in a two-dimensional layer of graphene, an approach that could be used to build nanoscale devices from the atomic level up for quantum-based applications. Credit: Carlos Jones/Oak Ridge National Laboratory, U.S. Dept. of Energy.

    Using this process, the scientists were further able to bring two, three and four silicon atoms together to build clusters and make them rotate within the graphene layer. Graphene is a two-dimensional, or 2D, layer of carbon atoms that exhibits unprecedented strength and high electrical conductivity. Dyck said he selected graphene for this work, because “it is robust against a 60-kilovolt electron beam.”

    “We can look at graphene for long periods of time without hurting the sample, compared with other 2D materials such as transition metal dichalcogenide monolayers, which tend to fall apart more easily under the electron beam,” he added.

    STEM has emerged in recent years as a viable tool for manipulating atoms in materials while preserving the sample’s stability.

    3
    With a STEM microscope, ORNL’s Ondrej Dyck brought two, three and four silicon atoms together to build clusters and make them rotate within a layer of graphene, a two-dimensional layer of carbon atoms that exhibits unprecedented strength and high electrical conductivity. Credit: Ondrej Dyck/Oak Ridge National Laboratory, U.S. Dept. of Energy.

    Dyck and ORNL colleagues Sergei Kalinin, Albina Borisevich and Stephen Jesse are among few scientists learning to control the movement of single atoms in 2D materials using the STEM. Their work supports an ORNL-led initiative coined The Atomic Forge, which encourages the microscopy community to reimagine STEM as a method to build materials from scratch.

    The fields of nanoscience and nanotechnology have experienced explosive growth in recent years. One of the earlier steps toward Feynman’s idea of building tiny machines atom by atom—a follow-on from his original theory of atomic manipulation first presented during his famous 1959 lecture—was seeded by the work of IBM fellow Donald Eigler. He had shown the manipulation of atoms using a scanning tunneling microscope.

    “For decades, Eigler’s method was the only technology to manipulate atoms one by one. Now, we have demonstrated a second approach with an electron beam in the STEM,” said Kalinin, director of the ORNL Institute for Functional Imaging of Materials. He and Jesse initiated research with the electron beam about four years ago.

    Successfully moving atoms in the STEM could be a crucial step toward fabricating quantum devices one atom at a time. The scientists will next try introducing other atoms such as phosphorus into the graphene structure.

    “Phosphorus has potential because it contains one extra electron compared to carbon,” Dyck said. “This would be ideal for building a quantum bit, or qubit, which is the basis for quantum-based devices.”

    Their goal is to eventually build a device prototype in the STEM.

    Dyck cautioned that while building a qubit from phosphorus-doped graphene is on the horizon, how the material would behave at ambient temperatures—outside of the STEM or a cryogenic environment—remains unknown.

    “We have found that exposing the silicon-doped graphene to the outside world does impact the structures,” he said.

    They will continue to experiment with ways to keep the material stable in non-laboratory environments, which is important to the future success of STEM-built atomically precise structures.

    “By controlling matter at the atomic scale, we are going to bring the power and mystery of quantum physics to real-world devices,” Jesse said.

    Co-authors of the paper titled, Building Structures Atom by Atom via Electron Beam Manipulation
    are Ondrej Dyck, Sergei V. Kalinin and Stephen Jesse of ORNL; Songkil Kim of Pusan National University in South Korea; Elisa Jimenez-Izal of the University of California and UPV/EHU and DIPC in Spain; and Anastassia N. Alexandrova of UPV/EHU and DIPC in Spain and the California NanoSystems Institute.

    The research was funded by ORNL’s Laboratory-Directed Research and Development program. Microscopy experiments were performed at the Center for Nanophase Materials Sciences, a DOE Office of Science User Facility.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    ORNL is managed by UT-Battelle for the Department of Energy’s Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time.

    i2

     
  • richardmitnick 10:58 am on September 27, 2018 Permalink | Reply
    Tags: , , Nanotechnology, , Researchers can watch changes happen over time millisecond by millisecond, The instrument offers scientists the ability and even ten times smaller down to one nanometer, VSANS   

    From NIST: “New NIST Instrument Will Give Scientists a Window on Change at the Nanoscale” 


    From NIST

    September 26, 2018

    Chad Boutin
    charles.boutin@nist.gov
    (301) 975-4261

    1
    Introducing the new Very Small Angle Neutron Scattering (VSANS) instrument, which will help scientists at the NIST Center for Neutron Research (NCNR) explore objects at the size scale important for nanotechnology.

    It looks more like a long water main pipe than a microscope, but a new custom-built instrument at the National Institute of Standards and Technology (NIST) will give scientists new ability to glimpse moment-by-moment changes in materials on the crucial nanometer scale.

    The tool’s name is almost as lengthy as its 45-meter footprint—it’s called the Very Small Angle Neutron Scattering (VSANS) instrument. Culminating from several years of in-house engineering, VSANS fills a gap in vision that U.S. researchers have craved for at least a decade: the ability to spot nanometer-scale changes in materials that could improve the medicines in your cabinet, the chips in your computer and even the soap in your shower.

    The scale where “things happen” in those and other materials is right between 10 and 1,000 nanometers—the realm of nanotechnology. A view at this size scale means you can watch how chains of molecules assemble themselves into more complicated structures or observe how a promising new prototype electronic switch changes from one configuration to another. Understanding these changes is key to harnessing them.

    “It’s the most critical length scale for seeing the emergent properties of materials,” said NIST’s Dan Neumann, a physicist at the NIST Center for Neutron Research (NCNR). “You want to know why it works the way it does, so you can improve it.”

    The instrument offers scientists the ability to see at this scale, and even ten times smaller, down to one nanometer. Moreover, researchers can watch changes happen over time, millisecond by millisecond. Other instruments at the NCNR use a similar approach as VSANS for peeking inside solid objects, but they do not provide structural information over such a broad length scale, nor can they reveal dynamic changes.

    Part of the instrument’s appeal is its ability to explore biology. Among the most important targets for drugs is also one of the most difficult to study: membrane proteins. Lodged within the protective outer membrane of our cells, these complicated molecules resist study because they are difficult to crystallize (a strategy useful for analyzing most other proteins), but comprehending their behavior is crucial for drug design.

    “Using neutrons, we can see these proteins as they look in their natural state,” said Kenneth Rubinson, a guest researcher from Wright State University in Ohio who has been performing experiments at the NCNR for 15 years. “We hope VSANS will let us get this data faster so we can get better models of the structure.”

    VSANS also allows its users to explore objects at multiple length scales simultaneously, providing more perspective than either scale alone would offer. For example, one approach for delivering drugs effectively involves encapsulating them in nanometer-sized bubbles called micelles so that they remain in the bloodstream as they travel to their targets. Seeing how these micelles behave and connect with one another appeals to NIST’s Elizabeth Kelley, an instrument scientist at the NCNR.

    “With other instruments, it’s like making a movie where you can only see half the picture at once,” she said. “I’ve lost a lot of time trying to optimize the location we’re looking at so we don’t miss anything, but with VSANS you don’t have that problem. Seeing how these micelles interact over time can help us understand how a drug can get released, or how efficient you are at encapsulating it.”

    Micelles also form in everyday products like shampoo. Tweaking their behavior might make all of us happier once we’re out of the shower.

    “We don’t think about it, but shampoo is actually a complex fluid made of nanoparticles and polymers, and their basic physical properties ultimately affects, for example, how much a shampoo dries out your hair,” said John Riley, who is finishing a National Research Council postdoctoral fellowship at the NCNR. “We’re just looking at the micelles’ basic properties here, but the more you know about those properties, the more you can control what that fluid does.”

    With VSANS, researchers at the NCNR expect many new discoveries in the pipeline.

    See the full article here.

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NIST Campus, Gaitherberg, MD, USA

    NIST Mission, Vision, Core Competencies, and Core Values

    NIST’s mission

    To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
    NIST’s vision

    NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.
    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

    NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

    Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
    Integrity: We are ethical, honest, independent, and provide an objective perspective.
    Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
    Excellence: We apply rigor and critical thinking to achieve world-class results and continuous improvement in everything we do.

     
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