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  • richardmitnick 7:31 am on February 27, 2018 Permalink | Reply
    Tags: , ETH Zurich, ,   

    From ETH Zürich: “Teaching quantum physics to a computer” 

    ETH Zurich bloc

    ETH Zürich

    26.02.2018
    Oliver Morsch

    An international collaboration led by ETH physicists has used machine learning to teach a computer how to predict the outcomes of quantum experiments. The results could prove to be essential for testing future quantum computers.

    1
    Using neural networks, physicists taught a computer to predict the results of quantum experiments. (Graphic: http://www.colourbox.com)

    Physics students spend many years learning to master the often counterintuitive laws and effects of quantum mechanics. For instance, the quantum state of a physical system may be undetermined until a measurement is made, and a measurement on one part of the system can influence the state of a distant part without any exchange of information. It is enough to make the mind boggle. Once the students graduate and start doing research, the problems continue: to exactly determine the state of some quantum system in an experiment, one has to carefully prepare it and make lots of measurements, over and over again.

    Very often, what one is actually interested in cannot even be measured directly. An international team of researchers led by Giuseppe Carleo, a lecturer at the Institute for Theoretical Physics of ETH Zürich, has now developed machine learning software that enables a computer to “learn” the quantum state of a complex physical system based on experimental observations and to predict the outcomes of hypothetical measurements. In the future, their software could be used to test the accuracy of quantum computers.

    Quantum physics and handwriting

    The principle of his approach, Carleo explains, is rather simple. He uses an intuitive analogy that avoids the complications of quantum physics: “What we do, in a nutshell, is like teaching the computer to imitate my handwriting. We will show it a bunch of written samples, and step by step it then learns to replicate all my a’s, l’s and so forth.”

    The way the computer does this is by looking at the ways, for instance, in which an “l” is written when it follows an “a”. These may not always be the same, so the computer will calculate a probability distribution that expresses mathematically how often a letter is written in a certain way when it is preceded by some other letter. “Once the computer has figured out that distribution, it could then reproduce something that looks very much like my handwriting”, Carleo says.

    2
    A neural network (top) “learns” the quantum state of a spin system from measurement data by trying different possibilities of the spin directions (bottom) and correcting itself step by step. (Graphic: ETH Zürich / G. Carleo)

    Quantum physics is, of course, much more complicated than a person’s handwriting. Still, the principle that Carleo (who recently moved to the Flatiron Institute in New York), together with Matthias Troyer, Guglielmo Mazzola (both at ETH) and Giacomo Torlai from the University of Waterloo as well as colleagues at the Perimeter Institute and the company D-Wave in Canada have used for their machine learning algorithm is quite similar.

    The quantum state of the physical system is encoded in a so-called neural network, and learning is achieved in small steps by translating the current state of the network into predicted measurement probabilities. Those probabilities are then compared to the actually measured data, and adjustments are made to the network in order to make them match better in the next round. Once this training period is finished, one can then use the quantum state stored in the neural network for “virtual” experiments without actually performing them in the laboratory.

    Faster tomography for quantum states

    “Using machine learning to extract a quantum state from measurements has a number of advantages”, Carleo explains. He cites one striking example, in which the quantum state of a collection of just eight quantum objects (trapped ions) had to be experimentally determined. Using a standard approached called quantum tomography, around one million measurements were needed to achieve the desired accuracy. With the new method, a much smaller number of measurements could do the same job, and substantially larger systems, previously inaccessible, could be studied.

    This is encouraging, since common wisdom has it that the number of calculations necessary to simulate a complex quantum system on a classical computer grows exponentially with the number of quantum objects in the system. This is mainly because of a phenomenon called entanglement, which causes distant parts of the quantum system to be intimately connected although they do not exchange information. The approach used by Carleo and his collaborators takes this into account by using a layer of “hidden” neurons, which allow the computer to encode the correct quantum state in a much more compact fashion.

    Testing quantum computers

    Being able to study quantum systems with a large number of components – or “qubits”, as they are often called – also has important implications for future quantum technologies, as Carleo points out: “If we want to test quantum computers with more than a handful of qubits, that won’t be possible with conventional means because of the exponential scaling. Our machine learning approach, however, should put us in a position to test quantum computers with as many as 100 qubits.”

    Also, the machine learning software can help experimental physicists by allowing them to perform virtual measurements that would be hard to do in the laboratory, such as measuring the degree of entanglement of a system composed of many interacting qubits. So far, the method has only been tested on artificially generated data, but the researchers plan to use it for analysing real quantum experiments very soon.

    Science paper:
    Torlai G, Mazzola G, Carrasquilla J, Troyer M, Melko R, Carleo G: Neural-network quantum state tomography. Nature Physics.

    See the full article here .

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    ETH Zurich campus
    ETH Zürich is one of the leading international universities for technology and the natural sciences. It is well known for its excellent education, ground-breaking fundamental research and for implementing its results directly into practice.

    Founded in 1855, ETH Zürich today has more than 18,500 students from over 110 countries, including 4,000 doctoral students. To researchers, it offers an inspiring working environment, to students, a comprehensive education.

    Twenty-one Nobel Laureates have studied, taught or conducted research at ETH Zürich, underlining the excellent reputation of the university.

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  • richardmitnick 3:41 pm on January 15, 2018 Permalink | Reply
    Tags: , ETH Zurich, , Quantum physics turned into tangible reality   

    From ETH Zürich: “Quantum physics turned into tangible reality” 

    ETH Zurich bloc

    ETH Zürich

    15.01.2018
    Felix Würsten

    ETH physicists have developed a silicon wafer that behaves like a topological insulator when stimulated using ultrasound. They have thereby succeeded in turning an abstract theoretical concept into a macroscopic product.

    1
    When the silicon wafer is stimulated at a single point using ultrasound, it begins to vibrate – but only at the corners. (Visualisation: ETH Zürich).

    The usual procedure goes like this: you have a complex physical system and attempt to explain its behaviour through as simple a model as possible. Sebastian Huber, Assistant Professor at the Institute for Theoretical Physics, has shown that this procedure also works in reverse: he develops macroscopic systems that exhibit exactly the same properties predicted by theory, but which have not yet been observed at this level.

    He succeeded in creating an illustrative example two and a half years ago. Together with his team, he built a mechanical device made of 270 pendulums connected by springs in such a way that the installation behaves like a topological insulator. This means that the pendulum and springs are positioned so that a vibrational excitation from the outside only moves the pendulums at the edges of the installation, but not the ones in the middle (as ETH News reported).

    Vibration only in the corners

    The new project, which will be published this week in the journal Nature, is also focused on a macroscopic system. This time, however, he created no large mechanical device, but a much more manageably-sized object. With his team, Huber created a 10 x 10 centimetre silicon wafer that consists of 100 small plates connected to each other via thin beams. The key aspect is that when the wafer is stimulated using ultrasound, only the plates in the corners vibrate; the other plates remain still, despite their connections.

    Huber drew his inspiration for the new material from a work published around a year ago by groups from Urbana-Champaign and Princeton; the researchers presented a new theoretical approach for a second-order topological insulator. “In a conventional topological insulator, the vibrations only spread across the surface, but not inside,” explains Huber. “The phenomenon is reduced by one dimension.” In the case of the pendulum installation, this means that the two-dimensional arrangement led to a one-dimensional vibration pattern along the edges.

    In a second-order topological insulator, however, the phenomenon is reduced by two dimensions. Accordingly, with a two-dimensional silicon wafer, the vibration no longer occurs along the edges, but only in the corners, at a zero-dimensional point. “We are the first to succeed in experimentally creating the predicted higher-order topological insulator,” says Huber.

    A new theoretical concept

    Huber has again created something that behaves in exactly the way predicted by the theory. To solve this “inverse problem”, he used a systematic process that he developed together with the group led by Chiara Daraio, now a professor at Caltech, and which he has published this week in the journal Nature Materials. Broadly speaking, Huber shows how a theoretically predicted functionality can be turned into concrete geometry. “In our example, we tested it using mechanical vibrations, by coupling elements with clearly defined modes of vibration using weak links,” says Huber. “But the process can also be transferred to other applications, such as to optical or electrical systems.”

    Expansion to the third dimension

    Huber already has clear plans for how to proceed: he wants to achieve a three-dimensional second-order topological insulator, in which the vibrations can be transmitted one-dimensionally. He recently received a Consolidator Grant from the European Research Council (ERC) for this project. Huber explains the basic idea: “We stack a number of these two-dimensional structures on top of each other, so that a three-dimensional form emerges. In this form, information or energy can be conducted from point A to point B through a one-dimensional channel.”

    Huber can think of a few possible applications. For example, such new topological insulators could be used to build robust and precise waveguides for communications networks. They could also be of use in the energy sector, for example for energy harvesting, in which energy from a diffuse surrounding source is focused for technological use.

    Also of interest to theoreticians

    Huber’s results will not only be of interest to engineers and materials researchers, but also theoretical physicists. “The key finding from a theoretical viewpoint is that certain second-order topological insulators cannot be mathematically described as a dipole, as conventional topological insulators are, but as quadrupoles, which are far more complex,” explains Huber. “The fact that we have been able to implement this experimentally in a macroscopic structure for the first time is therefore also a breakthrough for theoreticians.”

    See the full article here .

    Please help promote STEM in your local schools.

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    ETH Zurich campus
    ETH Zürich is one of the leading international universities for technology and the natural sciences. It is well known for its excellent education, ground-breaking fundamental research and for implementing its results directly into practice.

    Founded in 1855, ETH Zürich today has more than 18,500 students from over 110 countries, including 4,000 doctoral students. To researchers, it offers an inspiring working environment, to students, a comprehensive education.

    Twenty-one Nobel Laureates have studied, taught or conducted research at ETH Zürich, underlining the excellent reputation of the university.

     
  • richardmitnick 10:49 am on January 11, 2018 Permalink | Reply
    Tags: , Carbon cycle, , ETH Zurich, , Japan Trench, Radiocarbon dating   

    From ETH Zürich: “Earthquakes as a driver for the deep-ocean carbon cycle” 

    ETH Zurich bloc

    ETH Zürich

    09.01.2018
    Samuel Schlaefli

    An international team led by geologist Michael Strasser has used novel methods to analyse sediment deposits in the Japan Trench in order to gain new insights into the carbon cycle.

    1
    The research vessel RV Sonne, aboard which the sediment samples in the Japan Trench were taken in 2012. (Image: RF Forschungsschiffahrt Bremen/Germany)

    In a paper recently published in Nature Communications, geologist Michael Strasser presented the initial findings of a month-long research expedition off the coast of Japan. The research initiative had been organised in March 2012 by MARUM – Center for Marine Environmental Sciences. Strasser, who until 2015 was Assistant Professor for Sediment Dynamics at ETH Zürich and is now a Full Professor for Sediment Geology at the University of Innsbruck, took an international team there to study dynamic sediment remobilisation processes triggered by seismic activity.

    At a depth of 7,542 metres below sea level, the team took a core sample from the Japan Trench, an 800-km-long oceanic trench in the northwestern part of the Pacific Ocean. The trench, which is seismically active, was the epicentre of the Tohoku earthquake in 2011, which made headlines when it caused the nuclear meltdown at Fukushima. Such earthquakes wash enormous amounts of organic matter from the shallows down into deeper waters. The resulting sediment layers can thus be used later to glean information about the history of earthquakes and the carbon cycle in the deep ocean.

    New dating methods in the deep ocean

    The current study provided the researchers with a breakthrough. They analysed the carbon-rich sediments using radiocarbon dating. This method – measuring the amount of organic carbon as well as radioactive carbon (14C) in mineralised compounds – has long been a means of determining the age of individual sediment layers. Until now, however, it has not been possible to analyse samples from deeper than 5,000 metres below the surface, because the mineralised compounds dissolve under increased water pressure.

    Strasser and his team therefore had to use new methods for their analysis. One of these was what is known as the online gas radiocarbon method, developed by ETH doctoral student Rui Bao and the Biogeoscience Group at ETH Zürich. This greatly increases efficiency, since it takes just a single core sample to make more than one hundred 14C age measurements directly on the organic matter contained within the sediment.

    In addition, the researchers applied the Ramped PyrOx measurement method (pyrolysis) for the first time in the dating of deep-ocean sediment layers. This was done in cooperation with the Woods Hole Oceanographic Institute (U.S.), which developed the method. The process involves burning organic matter at different temperatures. Because older organic matter contains stronger chemical bonds, it requires higher temperatures to burn. What makes this method novel is that the relative age variation of the individual temperature fractions between two samples very precisely distinguishes the age difference between sediment levels in the deep sea.

    Dating earthquakes to increase forecast accuracy

    Thanks to these two innovative methods, the researchers could determine the relative age of organic matter in individual sediment layers with a high degree of precision. The core sample they tested contained older organic matter in three places, as well as higher rates of carbon export to the deep ocean. These places correspond to three historically documented yet hitherto partially imprecisely dated seismic events in the Japan Trench: the Tohoku earthquake in 2011, an unnamed earthquake in 1454, and the Sanriku earthquake in 869.

    At the moment, Strasser is working on a large-scale geological map of the origin and frequency of sediments in deep-ocean trenches. To do so, he is analysing multiple core samples taken during a follow-up expedition to the Japan Trench in 2016. “The identification and dating of tectonically triggered sediment deposits is also important for future forecasts about the likelihood of earthquakes,” Strasser says. “With our new methods, we can predict the recurrence of earthquakes with much more accuracy.”

    2
    Michael Strasser (right), then assistant professor at ETH Zürich, and expedition head Gerold Wefer, professor at MARUM and Bremen University, make recommendations about the core sample on board the RV Sonne. Source/Copyright: V. Diekamp, MARUM, Bremen University.

    Science team:
    Bao R, Strasser M, McNichol A, Haghipour N, McIntyre C Wefer G, Eglinton T.

    See the full article here .

    Please help promote STEM in your local schools.

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    ETH Zurich campus
    ETH Zürich is one of the leading international universities for technology and the natural sciences. It is well known for its excellent education, ground-breaking fundamental research and for implementing its results directly into practice.

    Founded in 1855, ETH Zürich today has more than 18,500 students from over 110 countries, including 4,000 doctoral students. To researchers, it offers an inspiring working environment, to students, a comprehensive education.

    Twenty-one Nobel Laureates have studied, taught or conducted research at ETH Zürich, underlining the excellent reputation of the university.

     
  • richardmitnick 10:30 am on January 11, 2018 Permalink | Reply
    Tags: , , ETH Zurich, Extremely bright and fast light emission, , ,   

    From ETH: “Extremely bright and fast light emission” 

    ETH Zürich bloc

    ETH Zürich

    11.01.2018
    Fabio Bergamin

    A type of quantum dot that has been intensively studied in recent years can reproduce light in every colour and is very bright. An international research team that includes scientists from ETH Zürich has now discovered why this is the case. The quantum dots could someday be used in light-emitting diodes.

    1
    A caesium lead bromide nanocrystal under the electron microscope (crystal width: 14 nanometres). Individual atoms are visible as points. (Photograph: ETH Zürich / Empa / Maksym Kovalenko)

    An international team of researchers from ETH Zürich, IBM Research Zürich, Empa and four American research institutions have found the explanation for why a class of nanocrystals that has been intensively studied in recent years shines in such incredibly bright colours. The nanocrystals contain caesium lead halide compounds that are arranged in a perovskite lattice structure.

    Three years ago, Maksym Kovalenko, a professor at ETH Zürich and Empa, succeeded in creating nanocrystals – or quantum dots, as they are also known – from this semiconductor material. “These tiny crystals have proved to be extremely bright and fast emitting light sources, brighter and faster than any other type of quantum dot studied so far,” says Kovalenko. By varying the composition of the chemical elements and the size of the nanoparticles, he also succeeded in producing a variety of nanocrystals that light up in the colours of the whole visible spectrum. These quantum dots are thus also being treated as components for future light-emitting diodes and displays.

    In a study published in the most recent edition of the scientific journal Nature, the international research team examined these nanocrystals individually and in great detail. The scientists were able to confirm that the nanocrystals emit light extremely quickly. Previously-studied quantum dots typically emit light around 20 nanoseconds after being excited when at room temperature, which is already very quick. “However, caesium lead halide quantum dots emit light at room temperature after just one nanosecond,” explains Michael Becker, first author of the study. He is a doctoral student at ETH Zürich and is carrying out his doctoral project at IBM Research.

    2
    A sample with several green glowing perovskite quantum dots excited by a blue laser. (Photograph: IBM Research / Thilo Stöferle)

    Electron-hole pair in an excited energy state

    Understanding why caesium lead halide quantum dots are not only fast but also very bright entails diving into the world of individual atoms, light particles (photons) and electrons. “You can use a photon to excite semiconductor nanocrystals so that an electron leaves its original place in the crystal lattice, leaving behind a hole,” explains David Norris, Professor of Materials Engineering at ETH Zürich. The result is an electron-hole pair in an excited energy state. If the electron-hole pair reverts to its energy ground state, light is emitted.

    Under certain conditions, different excited energy states are possible; in many materials, the most likely of these states is called a dark one. “In such a dark state, the electron hole pair cannot revert to its energy ground state immediately and therefore the light emission is suppressed and occurs delayed. This limits the brightness”, says Rainer Mahrt, a scientist at IBM Research.

    No dark state

    The researchers were able to show that the caesium lead halide quantum dots differ from other quantum dots: their most likely excited energy state is not a dark state. Excited electron-hole pairs are much more likely to find themselves in a state in which they can emit light immediately. “This is the reason that they shine so brightly,” says Norris.

    The researchers came to this conclusion using their new experimental data and with the help of theoretical work led by Alexander Efros, a theoretical physicist at the Naval Research Laboratory in Washington. He is a pioneer in quantum dot research and, 35 years ago, was among the first scientists to explain how traditional semiconductor quantum dots function.

    Great news for data transmission

    As the examined caesium lead halide quantum dots are not only bright but also inexpensive to produce they could be applied in television displays, with efforts being undertaken by several companies, in Switzerland and world-wide. “Also, as these quantum dots can rapidly emit photons, they are of particular interest for use in optical communication within data centres and supercomputers, where fast, small and efficient components are central,” says Mahrt. Another future application could be the optical simulation of quantum systems which is of great importance to fundamental research and materials science.

    ETH professor Norris is also interested in using the new knowledge for the development of new materials. “As we now understand why these quantum dots are so bright, we can also think about engineering other materials with similar or even better properties,” he says.

    Science team:
    Becker MA, Vaxenburg R, Nedelcu G, Sercel PC, Shabaev A, Mehl MJ, Michopoulos JG, Lambrakos SG, Bernstein N, Lyons JL, Stöferle T, Mahrt RF, Kovalenko MV, Norris DJ, Rainò G, Efros AL.

    See the full article here .

    Please help promote STEM in your local schools.

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    ETH Zürich campus
    ETH Zürich is one of the leading international universities for technology and the natural sciences. It is well known for its excellent education, ground-breaking fundamental research and for implementing its results directly into practice.

    Founded in 1855, ETH Zürich today has more than 18,500 students from over 110 countries, including 4,000 doctoral students. To researchers, it offers an inspiring working environment, to students, a comprehensive education.

    Twenty-one Nobel Laureates have studied, taught or conducted research at ETH Zürich, underlining the excellent reputation of the university.

     
  • richardmitnick 10:26 am on September 17, 2017 Permalink | Reply
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    From ETH Zürich: Women in STEM- “At home in the world of cold atoms” Physicist Laura Corman 

    ETH Zurich bloc

    ETH Zürich

    16.09.2017
    Isabelle Herold

    1
    Laura Corman plunges into the world of cold atoms (Image: Annick Ramp/ETH Zürich)

    Physicist Laura Corman is fascinated by the behaviour of electrons in solids. But this up and coming researcher’s other interests give her plenty of opportunities to get out of the lab.

    For most people, the world of cold atoms is likely to be somewhat of an enigma. In contrast, Laura Corman (a postdoctoral researcher at the Institute for Quantum Electronics) can’t hide her enthusiasm when she explains how atoms suddenly become visible and gather into clouds. For her, this is a unique visual experience – almost magical. The cooling of atoms to near absolute zero allows scientists to draw conclusions about the behaviour of electrons in solids.

    Laura Corman enjoys popularising science and succeeded in taking her complex subject through to the finals of the competition “Ma thèse en 180 secondes” (My thesis in 180 seconds). Here, she compared atoms to the spectators in the hall: If they have time, they occupy an even spread of seats. If you stop them abruptly, however, there are gaps here and collisions there. “After that, even my grandmother understood what my work is about,” the 29-year-old says.

    Corman discovered her passion for science as a ten-year-old when she visited an amateur observatory during the summer holidays in Provence. She is enormously grateful to her parents – her father is an engineer in the automobile industry, her mother a teacher – for giving her and her younger brother the opportunity to discover different worlds from an early age.

    When she went to university, she moved from the northernmost tip of France to Paris. There, whole new horizons once again opened up before her: “As I experimented with my own projects, I increasingly understood how things were connected.” In her spare time, she became involved in an association helping socially disadvantaged children to learn mathematics and physics.

    In the minority

    When it came to studying for her Master’s in physics, she toyed with the idea of an exchange in the USA. Then some colleagues brought ETH to her attention, and she applied immediately. The interest was mutual: ETH offered Corman an Excellence Scholarship, and her move to Switzerland was settled. To round off her year, she received the Willi Studer Prize for her outstanding mark in her final Master’s examination.

    As a woman, she has always been in a minority within her subject. As far as she is concerned, though, this has hardly made any difference – or rather, just once. This was when Corman felt that she was getting less interesting work to do than her male colleagues during an industrial internship. Being a direct person, she refused to accept that. In hindsight, she wondered to what extent the problem really had to do with the fact she is a woman, or whether perhaps prejudices were distorting her perception. “Men probably never ask themselves questions like that,” Corman acknowledges thoughtfully.

    2
    Laura Corman, Postdoctoral researcher at the Institute for Quantum Electronics

    When Professor of Quantum Optics Tilman Esslinger invited her to return to his laboratory at ETH after her doctorate in Paris, she did not hesitate for a moment. The team is fantastic, the infrastructure and support superb, says Corman. She is now receiving support from the ETH fellowship programme for promising postdoctoral researchers, although she still finds it a huge challenge to give lectures in German. In order to improve their language skills and make some contacts, she and her partner play handball at the ASVZ. “Whether it’s handball or German, we are total beginners in both,” she laughs.

    Corman is adamant that she would continue to pursue her career, even if she were to become a mother someday. In France that’s the norm, she explains, although the conditions there are somewhat different: a single income is not usually enough to get by, but then day care places are affordable and in sufficient supply. Corman gets annoyed that it is often only women who are confronted with the issue of reconciling work and family life. Nowadays that’s just as much a matter for men, and it’s mainly a question of organisation.

    Where her career path will one day lead her still remains to be seen: “It would be fantastic to establish my own group at a university. But exciting possibilities might be lying in wait in other places too – everything is left to play for.”

    See the full article here .

    Please help promote STEM in your local schools.

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    ETH Zurich campus
    ETH Zurich is one of the leading international universities for technology and the natural sciences. It is well known for its excellent education, ground-breaking fundamental research and for implementing its results directly into practice.

    Founded in 1855, ETH Zurich today has more than 18,500 students from over 110 countries, including 4,000 doctoral students. To researchers, it offers an inspiring working environment, to students, a comprehensive education.

    Twenty-one Nobel Laureates have studied, taught or conducted research at ETH Zurich, underlining the excellent reputation of the university.

     
  • richardmitnick 4:39 pm on July 13, 2017 Permalink | Reply
    Tags: , ETH Zurich, , Testing a soft artificial heart   

    From ETH Zürich: “Testing a soft artificial heart” 

    ETH Zurich bloc

    ETH Zürich

    13.07.2017
    Franziska Schmid

    ETH researchers from the Functional Materials Laboratory have developed a silicone heart that beats almost like a human heart. In collaboration with colleagues from the Product Development Group Zürich, they have tested how well it works.

    1
    The artificial heart imitates a human heart as closely as possible. (Photo: Zürich Heart)

    It looks like a real heart. And this is the goal of the first entirely soft artificial heart: to mimic its natural model as closely as possible. The silicone heart has been developed by Nicholas Cohrs, a doctoral student in the group led by Wendelin Stark, Professor of Functional Materials Engineering at ETH Zürich. The reasoning why nature should be used as a model is clear. Currently used blood pumps have many disadvantages: their mechanical parts are susceptible to complications while the patient lacks a physiological pulse, which is assumed to have some consequences for the patient.

    “Therefore, our goal is to develop an artificial heart that is roughly the same size as the patient’s own one and which imitates the human heart as closely as possible in form and function,” says Cohrs. A well-functioning artificial heart is a real necessity: about 26 million people worldwide suffer from heart failure while there is a shortage of donor hearts. Artificial blood pumps help to bridge the waiting time until a patient receives a donor heart or their own heart recovers.

    The soft artificial heart was created from silicone using a 3D-printing, lost-wax casting technique; it weighs 390 grams and has a volume of 679 cm3. “It is a silicone monoblock with complex inner structure,” explains Cohrs. This artificial heart has a right and a left ventricle, just like a real human heart, though they are not separated by a septum but by an additional chamber. This chamber is in- and deflated by pressurized air and is required to pump fluid from the blood chambers, thus replacing the muscle contraction of the human heart.


    The artificial heart at work (Video: ETH Zürich)

    Thinking in a new direction

    Anastasios Petrou, a doctoral student of the Product Development Group Zürich, led by Professor Mirko Meboldt evaluated the performance of this soft artificial heart. The young researchers have just published the results of the experiments in the scientific journal Artificial Organs.

    They proved that the soft artificial heart fundamentally works and moves in a similar way to a human heart. However, it still has one problem: it currently lasts for about only 3,000 beats, which corresponds to a lifetime of half to three quarters of an hour. After that, the material can no longer withstand the strain. Cohrs explains: “This was simply a feasibility test. Our goal was not to present a heart ready for implantation, but to think about a new direction for the development of artificial hearts.” Of course, the tensile strength of the material and the performance would have to be enhanced significantly.

    Zürich Heart brings researchers together

    Cohrs and Petrou met in the Zürich Heart Project, a flagship project of University Medicine Zurich that brings together 20 research groups from various disciplines and institutions in Zürich and Berlin. Part of the research focuses on improvements on existing blood pumps, such as how to reduce blood damage induced from the mechanical parts of the pump, while others explore extremely elastic membranes or more biocompatible surfaces. This is done in close collaboration with the clinicians in Zurich and Berlin.

    The lively exchanges among the researchers also helped this Zürich Heart sub-project. Doctoral students of Product Development Group Zürich, who are working on new technologies for blood pumps, have developed a testing environment with which they can simulate the human cardiovascular system. The researchers of the silicone heart made use of this testing environment for their development process which also included the use of a fluid with comparable viscosity as human blood. “Currently, our system is probably one of the best in the world,” says Petrou proudly.

    Researching the heart is an appealing task, and Cohrs and Petrou would both like to remain in this research field. “As a mechanical engineer, I would never have thought that I would ever hold a soft heart in my hands. I’m now so fascinated by this research that I would very much like to continue working on the development of artificial hearts,” says Petrou.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ETH Zurich campus
    ETH Zurich is one of the leading international universities for technology and the natural sciences. It is well known for its excellent education, ground-breaking fundamental research and for implementing its results directly into practice.

    Founded in 1855, ETH Zurich today has more than 18,500 students from over 110 countries, including 4,000 doctoral students. To researchers, it offers an inspiring working environment, to students, a comprehensive education.

    Twenty-one Nobel Laureates have studied, taught or conducted research at ETH Zurich, underlining the excellent reputation of the university.

     
  • richardmitnick 2:06 pm on June 19, 2017 Permalink | Reply
    Tags: , , ETH Zurich, Piz Daint, PRACE - Partnership for Advanced Computing in Europe,   

    From ETH: “Piz Daint is a world leader” 

    ETH Zurich bloc

    ETH Zürich

    19.06.2017
    Anna Maltsev
    Felix Würsten

    Cray Piz Daint supercomputer of the Swiss National Supercomputing Center (CSCS)

    After an extensive hardware upgrade at the end of last year, the CSCS supercomputer Piz Daint is now the most powerful mainframe computer outside Asia. With a peak performance in excess of 20 petaflops, it will enable pioneering research in Switzerland and Europe.

    The Piz Daint supercomputer at the Swiss National Supercomputing Centre (CSCS) has been the most powerful supercomputer in Europe since November 2013. An extensive hardware upgrade at the end of 2016 has now more than tripled its performance. Piz Daint is now the fastest computer outside Asia, with a theoretical peak performance of 25.3 petaflops, as confirmed today at the international ISC High Performance event in Frankfurt. Thanks to its innovative architecture, Piz Daint is also one of the most energy-efficient mainframe computer in the world.

    Strategic approach

    The upgraded supercomputer is an energy-efficient hybrid system consisting of conventional processors (CPUs) and graphics processors (GPUs). The sophisticated system, based on a Cray XC40/XC50, is the result of a long-standing collaboration between CSCS, various hardware manufacturers, computer scientists, mathematicians and other researchers from different disciplines. This successful collaboration was initiated by the national Strategic Plan for High Performance Computing and Networking (HPCN Strategy) that was launched by the ETH Board on behalf of the federal government in 2009.

    Support for research

    Supercomputers are now an integral part of research: in addition to theory and experiments, simulations, data analyses and visualisations now also make key contributions to most research areas. Powerful systems such as Piz Daint are crucial for high-resolution computer-intensive simulations, such as those used in climate or material research, or in the life sciences.

    In data science, which has an increasingly important role and is one of ETH Zürich’s main focus areas, supercomputers enable the analysis of enormous amounts of data. This is an area in which Piz Daint is particularly strong: it is able to analyse the resulting data while the calculations are still ongoing.

    Important for international cooperation

    Piz Daint is also an important element in international research collaborations: as of this spring, CSCS with Piz Daint is one of the main providers of computing power in the Partnership for Advanced Computing in Europe (PRACE). This commitment then benefits Swiss researchers in turn, as CSCS’s participation in PRACE gives them access to various other European supercomputers.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ETH Zurich campus
    ETH Zurich is one of the leading international universities for technology and the natural sciences. It is well known for its excellent education, ground-breaking fundamental research and for implementing its results directly into practice.

    Founded in 1855, ETH Zurich today has more than 18,500 students from over 110 countries, including 4,000 doctoral students. To researchers, it offers an inspiring working environment, to students, a comprehensive education.

    Twenty-one Nobel Laureates have studied, taught or conducted research at ETH Zurich, underlining the excellent reputation of the university.

     
  • richardmitnick 3:30 pm on December 9, 2016 Permalink | Reply
    Tags: , ETH Zurich, , New weapon against Diabetes   

    From ETH Zürich: “New weapon against Diabetes” 

    ETH Zurich bloc

    ETH Zürich

    08.12.2016
    Peter Rüegg

    Researchers have used the simplest approach yet to produce artificial beta cells from human kidney cells. Like their natural model, the artificial cells act as both sugar sensors and insulin producers.

    1
    Repeated measurement of the blood glucose level and injection of insulin make the everyday life of diabetics complicated. The newly created beta cells of the ETH researchers could make life easier again. (Picture: Dolgachov / iStock)

    Researchers led by ETH Professor Martin Fussenegger at the Department of Biosystems Science and Engineering (D-BSSE) in Basel have produced artificial beta cells using a straightforward engineering approach. These pancreatic cells can do everything that natural ones do: they measure the glucose concentration in the blood and produce enough insulin to effectively lower the blood sugar level. The ETH researchers presented their development in the latest edition of the journal Science.

    Previous approaches were based on stem cells, which the scientists allowed to mature into beta cells either by adding growth factors or by incorporating complex genetic networks.

    For their new approach, the ETH researchers used a cell line based on human kidney cells, HEK cells. The researchers used the natural glucose transport proteins and potassium channels in the membrane of the HEK cells. They enhanced these with a voltage-dependent calcium channel and a gene for the production of insulin and GLP-1, a hormone involved in the regulation of the blood sugar level.

    Voltage switch causes insulin production

    In the artificial beta cells, the HEK cells’ natural glucose transport protein carries glucose from the bloodstream into the cell’s interior. When the blood sugar level exceeds a certain threshold, the potassium channels close. This flips the voltage distribution at the membrane, causing the calcium channels to open. As calcium flows in, it triggers the HEK cells’ built-in signalling cascade, leading to the production and secretion of insulin or GLP-1.

    2
    Diagram of a HEK-beta cell: Extracellular glucose triggers glycolysis-dependent membrane depolarization, which activates the voltage-gated calcium channel, resulting in an influx of Calcium ions, induction of the calmodulincalcineurin signaling cascade, and PNFAT-mediated induction of insulin secretion. (Graphics: ETH Zürich)

    The initial tests of the artificial beta cells in diabetic mice revealed the cells to be extremely effective: “They worked better and for longer than any solution achieved anywhere in the world so far,” says Fussenegger. When implanted into diabetic mice, the modified HEK cells worked reliably for three weeks, producing sufficient quantities of the messengers that regulate blood sugar level.

    Helpful modelling

    In developing the artificial cells, the researchers had the help of a computer model created by researchers working under Jörg Stelling, another professor in ETH Zürich’s Department of Biosystems Science and Engineering (D-BSSE). The model allows predictions to be made of cell behaviour, which can be verified experimentally. “The data from the experiments and the values calculated using the models were almost identical,” says Fussenegger.

    He and his group have been working on biotechnology-based solutions for diabetes therapy for a long time. Several months ago, they unveiled beta cells that had been grown from stem cells from a person’s fatty tissue. This technique is expensive, however, since the beta cells have to be produced individually for each patient. The new solution would be cheaper, as the system is suitable for all diabetics.

    Market-readiness is a long way off

    It remains uncertain, though, when these artificial beta cells will reach the market. They first have to undergo various clinical trials before they can be used in humans. Trials of this kind are expensive and often last several years. “If our cells clear all the hurdles, they could reach the market in 10 years,” the ETH professor estimates.

    Diabetes is becoming the modern-day scourge of humanity. The International Diabetes Federation estimates that more than 640 million people worldwide will suffer from diabetes by 2040. Half a million people are affected in Switzerland today, with 40,000 of them suffering from type 1 diabetes, the form in which the body’s immune system completely destroys the insulin-producing beta cells.

    Reference

    Xie M et al. Beta-cell-mimetic designer cells provide closed-loop glycemic control. Science, Advanced Online Publication, 8 November 2016, DOI: 10.1126/science.aaf4006

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ETH Zurich campus
    ETH Zurich is one of the leading international universities for technology and the natural sciences. It is well known for its excellent education, ground-breaking fundamental research and for implementing its results directly into practice.

    Founded in 1855, ETH Zurich today has more than 18,500 students from over 110 countries, including 4,000 doctoral students. To researchers, it offers an inspiring working environment, to students, a comprehensive education.

    Twenty-one Nobel Laureates have studied, taught or conducted research at ETH Zurich, underlining the excellent reputation of the university.

     
  • richardmitnick 2:48 pm on October 27, 2016 Permalink | Reply
    Tags: , , ETH Zurich, How planets like Jupiter form   

    From ETH Zürich 

    ETH Zurich bloc

    ETH Zürich

    10.27.16
    Barbara Vonarburg

    Young giant planets are born from gas and dust. Researchers of ETH Zürich and the Universities of Zürich and Bern simulated different scenarios relying on the computing power of the Swiss National Supercomputing Centre (CSCS) to find out how they exactly form and evolve. They compared their results with observations and were able to show amongst others a big difference between the postulated formation mechanisms.

    1
    Core accretion: A 10 Jupiter-mass planet is formed and is placed at 50 AU from the star. The planet has opened a gap in the circumstellar disk. (Image: J. Szulagyi, JUPITER code)

    Astronomers set up two theories explaining how gaseous giant planets like Jupiter or Saturn could be born. A bottom-up formation mechanism states that first, a solid core is aggregated of roughly ten times the size of the Earth. «Then, this core is massive enough to attract a significant amount of gas and keep it,» explains Judit Szulágyi, post-doctoral fellow at the ETH Zürich and member of the Swiss NCCR PlanetS. The second theory is a top-down formation scenario: Here the gaseous disk around the young star is so massive, that due to self-gravity of the gas-dust, spiral arms are forming with clumps inside. Then, these clumps collapse via their own gravity directly into a gaseous planet, similar to how stars form. The first mechanism is called «core-accretion», the second one «disk instability». In both cases, a disk forms around the gas-giants, called the circumplanetary disk, which will serve as a birth-nest for satellites to form.

    To find out which mechanism actually takes place in the Universe, Judit Szulágyi and Lucio Mayer, Professor at the University of Zürich, simulated the scenarios on Piz Daint supercomputer at the Swiss National Supercomputing Centre (CSCS) in Lugano. «We pushed our simulations to the limits in terms of the complexity of the physics added to the models,» explains Judit Szulágyi: «And we achieved higher resolution than anybody before.» In their studies published in the «Monthly Notices of the Royal Astronomical Society» the researchers found a big difference between the two formation mechanisms: In the disk instability scenario the gas in the planet’s vicinity remained very cold, around 50 Kelvins, whereas in the core accretion case the circumplanetary disk was heated to several hundreds of Kelvins. «The disk instability simulations are the first that can resolve the circumplanetary disk around multiple protoplanets, using tens of millions of resolution elements in the computational domain. We exploited Piz Daint to accelerate the calculations using Graphics Processing Units (GPUs)” adds Mayer.

    This huge temperature difference is easily observable. «When astronomers look into new forming planetary systems, just measuring the temperatures in the planet’s vicinity will be enough to tell which formation mechanism built the given planet,» explains Judit Szulágyi. A first comparison of the calculated and observed data seems to favour the core accretion theory. Another difference that was expected didn’t show up in the computer simulation. Before, astrophysics thought that the circumplanetary disk significantly differs in mass in the two formation scenarios. «We showed that this is not true,» says the PlanetS member.

    2
    Gravitational instability simulation: Two snapshots in the early and late stage of the simulation at 780 years and 1942 years. The second snapshot shows only 4 clumps remaining among those initially formed. (Image: Lucio Mayer & T. Quinn, ChaNGa code)

    Luminous shock front detected

    Regarding the size of the new born planet, observations can be misleading as the astrophysicist found in a second study together with Christoph Mordasini, Professor at the University of Bern. In the core accretion model the researchers had a closer look at the disk around planets with masses three to ten times bigger than Jupiter’s. The computer simulations showed that gas falling on the disk from the outside heats up and creates a very luminous shock front on the disk’s upper layer. This significantly alters the observational appearance of young, forming planets.

    «When we see a luminous spot inside a circumplanetary disk, we cannot be sure whether we see the planet luminosity, or also the surrounding disk luminosity,» says Judit Szulágyi. This may lead to an overestimation of the planet’s mass of up to four times. «So maybe an observed planet has only the same mass as Saturn instead of some Jupiter masses,» concludes the scientist.

    In their simulations the astrophysicists mimicked the formation processes by using the basic physical laws such as gravity or the hydrodynamical equations of the gas. Because of the complexity of the physical models the simulations were very time consuming, even on Europe’s fastest supercomputer at CSCS: «On the order of nine months running time on hundreds to several thousands of computing cores» estimates Judit Szulágyi: «This means that on one computing core it would have taken longer than my entire lifetime.»

    Yet there are still challenges ahead. Simulations of disk instability still do not cover a long timescale. It is possible that after the protoplanet has collapsed to the density of Jupiter its disk will heat up more like in core-accretion. Likewise, the hotter gas found in the core-accretion case would be partially ionized, a favourable environment for effects of magnetic fields, completely neglected so far. Running even more expensive simulations with a richer description of the physics will be the next step. (bva)

    Publications:
    Szulagyi; L. Mayer; T. Quinn: Circumplanetary disks around young giant planets: a comparison between core-accretion and disk instability, Monthly Notices of the Royal Astronomical Society 2016;
    doi: 10.1093/mnras/stw2617

    Szulagyi; C. Mordasini: Thermodynamics of Giant Planet Formation: Shocking Hot Surfaces on Circumplanetary Disks, Monthly Notices of the Royal Astronomical Society: Letters 2016;
    doi: 10.1093/mnrasl/slw212

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    ETH Zurich campus
    ETH Zurich is one of the leading international universities for technology and the natural sciences. It is well known for its excellent education, ground-breaking fundamental research and for implementing its results directly into practice.

    Founded in 1855, ETH Zurich today has more than 18,500 students from over 110 countries, including 4,000 doctoral students. To researchers, it offers an inspiring working environment, to students, a comprehensive education.

    Twenty-one Nobel Laureates have studied, taught or conducted research at ETH Zurich, underlining the excellent reputation of the university.

     
  • richardmitnick 11:43 am on September 27, 2016 Permalink | Reply
    Tags: Book Anna Garry Thomas Feurer A Journey into Time in Powers of Ten, ETH Zurich, Expanding the horizons of experience, NCCR MUST, , Ultrafast processes, Ultrashort research   

    From ETH Zürich: “Ultrafast processes in the blink of an eye” 

    ETH Zurich bloc

    ETH Zürich

    26.09.2016
    Florian Meyer

    Ultrafast processes beyond the human imagination occur in nature, but basic research has been able to measure and explore them only since the turn of the millennium. A book and an exhibition by the National Centre of Competence in Research Molecular Ultrafast Science and Technology (NCCR MUST) now connect this to everyday life by inviting you on a journey into time.

    1
    In recent years, ultrafast laser physics – such as Ursula Keller’s Attoline laboratory – has ventured into increasingly smaller units of time: today, measurements are possible in the attosecond or trillionth of a second range. (Photo: ETH Zurich/H. Hostettler)

    The exhibition, which is located in the entrance of Campus Info at ETH Hönggerberg until mid-December, can be enjoyed in no time at all. The name says it all – “Fast”. Several posters present image sequences with processes that take place very quickly – or slowly – and at the same time provide an insight into “ultrafast research”.

    Some processes occur so quickly in nature that the blink of an eye is by comparison very slow. A light wave, for example, is ultrafast, rising and falling again in a mere two quadrillionths of a second. In scientific terms, this is two femtoseconds or, when written as the power of ten, 2·10−15 seconds.

    Even faster are elementary particles such as electrons or photons: when they move in molecules, it takes an ultrafast 100 trillionths of a second, which is 100 attoseconds or 10−16 s. No one is able to see such ultrafast processes with the naked eye, and even for basic research it is comparatively uncharted territory.

    Expanding the horizons of experience

    Basic and essential physical, chemical and biological reactions take place in the ultrafast time scale between nanoseconds (10−9 s) and attoseconds (10−18 s). Understanding them can help in the development of alternative sources of energy, new data storage and medical applications, such as artificial blood.

    “The human senses perceive light and speed in only a very limited manner,” says Ursula Keller. “This is why we are attempting to expand the horizons of experience through research.” Throughout her career, the ETH Professor of Experimental Physics has contributed to the research to venture into increasingly smaller units of time.

    Only since the turn of the millennium has basic research been able to measure and investigate processes in the attosecond range. The breakthrough came thanks to the development of new light sources, such as the new X-ray radar SwissFEL at the Paul Scherrer Institute, based on ultrashort light and laser pulses.

    Today, “ultrafast research” comprises subjects such as physics, chemistry, biology and materials science, which are linked together at NCCR MUST. Keller is the co-director of MUST and her Ultrafast Laser Physics group has contributed to the rapid development.

    Linking ultrashort research and everyday life

    Uncharted territory for research poses a challenge for public communication and the dissemination of knowledge to schools, as neither ultrafast processes nor the research technologies and mathematical notations and models used to explore them are really tangible to lay people.

    To establish a link between “ultrashort research” and everyday life, Thomas Feurer, co-director of NCCR MUST and a physics professor at the University of Bern, and Anna Garry, responsible for public communication at NCCR MUST, pursued an idea that had come to Jürg Osterwalder, Professor of Surface Physics at the University of Zurich, while he was on the train.

    The idea was to invite non-specialists on a journey into ultrafast processes. The result was the book A Journey into Time in Powers of Ten, as well as exhibitions at Scientifica 2015, the Festival de Science 2016 in Neuchâtel and now at Hönggerberg. The material is also being used in exchanges with schools.

    “We would like to make schools and the public excited about our research, inspire them to think about time and the duration of essential processes, and show them how these processes can be expressed numerically,” says Garry, relating how her six-year-old nephew was fascinated by the series of images and immediately asked questions.

    The starting point of the journey into time – in both the book and the exhibition – is the blink of an eye: this takes one second or 100 s. In everyday life, blinking is the smallest felt unit in which a human perceives events in their environment. Proceeding from this, the journey travels ten steps from blinking to the attosecond.

    Each step corresponds to a power of ten and is connected to one aspect of ultrafast research by a short story. In addition to scientific facts, excerpts from the daily lives of the researchers also appear, rendering numerical reflections about essential processes clear and comprehensible.

    Insight into fast and slow processes

    A person has a thought in a tenth of a second or 10-1 s. Walking 100 metres takes about ten seconds or 101 s. Someone travelling by train from Zurich to Geneva requires 2¾ hours or 104 s. Conversely, lightning takes only 10-4 s.

    A doctoral student in their fourth year has put in about 108 s towards their education, whereas a jellyfish in the sea needs only 10-8 s to glow green. “We can easily imagine the step from blinking to sprinting. So when we take these ten steps ten times, we arrive at our research in a way that can be understood,” says Feurer.

    “As many people find it much more difficult to imagine powers of ten in the minus range than in the plus range, we have juxtaposed the slow processes with the fast.” The slowest process presented in the book and exhibition is the formation of the Milky Way, which has been dragging on for more than 30 billion years or 10^18 s.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ETH Zurich campus
    ETH Zurich is one of the leading international universities for technology and the natural sciences. It is well known for its excellent education, ground-breaking fundamental research and for implementing its results directly into practice.

    Founded in 1855, ETH Zurich today has more than 18,500 students from over 110 countries, including 4,000 doctoral students. To researchers, it offers an inspiring working environment, to students, a comprehensive education.

    Twenty-one Nobel Laureates have studied, taught or conducted research at ETH Zurich, underlining the excellent reputation of the university.

     
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