Institute of Applied Physics

Nizhny, Russia

Institute of Applied Physics

Nizhny, Russia
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News Article | February 13, 2017
Site: www.theenergycollective.com

All future foreign nuclear reactors to be 1200 MW or more (Press Trust India) The government has decided that all future foreign atomic reactors in India will have a capacity to generate 1200 MW and above, in a bid to augment nuclear power generation. “We already have foreign power plants with a capacity of 1000 MWs (Kudankulam). The technology too has advanced that we have reactors with such a capacity. If we are installing them, then might as well have reactors that can generate more power and make optimum use of it,” a senior government official said. The comment stirred immediate interest in the fate and future of plans for Westinghouse to build six AP1000 reactors for NPCIL. The Indian government recently agreed to increase the capacity of six AP-1000 reactors, to be built by USA’s Westinghouse Co in Kovvada in Andhra Pradesh, to 1208 MW each. The six proposed nuclear power reactors to be built by Areva in Jaitapur in Maharashtra will have capacity of 1650 MW each. According to sources, the second site to be allocated to the Russians at Kavali in Andhra Pradesh for its proposed nuclear power park will also have atomic reactors with an enhanced capacity of 1200 MW. The existing VVER reactors built by Russians at Kudankulam in Tamil Nadu have a capacity of 1000 MW each. The first two units have been commissioned and Russia will build four more units at the site. Rostom is supply its 1200 MW models to Turkey where there are plans to build four of them at a coastal site. India’s plans for 1200 MW units will be little less than twice the capacity of indigenously developed Pressurized Heavy Water Reactors (PHWRs) in the country. The current PHWRs in operation have capacity to generate between 220 MW to 540 MW. The Department of Atomic Energy (DAE) is already constructing its indigenous PHRWs with a capacity of 700 MW. There could be political resistance to this decision. Some interests want India to only build indigenous designs and to keep foreign vendors out of the market. India’s coal mining interests have successfully blocked U.S. vendors from entering the market by supporting the supplier liability law. India faces a shortage of nuclear engineers and does not have a plant to make the large forgings needed to build reactor pressure vessels. Financing is going to be a problem. NPCIL does not have the funding and there are limits to financing from vendors like Westinghouse and Areva. The former is hobbled by the financial troubles of Toshiba, its parent firm. Areva has just been recapitalized by the French government, but is not in a position to finance six new reactors for India. India has explored getting financial support for the Westinghouse reactors from the U.S. Export-Import bank, but Congress is unlikely to raise the bank’s lending authority to cover the the estimated 20 billion, or more, in costs while faced with demands for investments for infrastructure in the nation’s roads and bridges at home. For Westinghouse to proceed with the project it will have to emerge from under the shadow of Toshiba’s financial troubles and settle its disputes with Chicago Bridge & Iron. The firm could thrive if it returns to a role of being a vendor of reactor technology rather than an integrated supplier and EPC firm. That process could take a year or two. (Economic Times) The Department of Atomic Energy will construct two Prototype Fast Breeder Reactors (PFBR) of 600 MW each at Kalpakkam in Tamil Nadu, besides the present one of 500 MW capacity which is expected to go fully functional by October. “All the construction activities of PFBR have been completed and the integrated commissioning activities have started. PFBR is expected to go fully functional by October 2017. The 500 MW PFBR, which is to be functional by October, will be the first PFBR in the world for commercial use. China’s First Haixang AP1000 To Begin Operation In 2020 (NucNet) The state-run China Daily reports that first nuclear reactor unit at the Haixang nuclear station in Hebei province, northeastern China, is expected to come online by 2020 and will use Westinghouse AP1000 reactor technology. The wire service said construction work began at Haixang last year, although the station is not yet listed in the International Atomic Energy Agency’s Power Reactor Information System (Pris) database. In 2014 the project company, China Nuclear Huadian Hebei Nuclear Power Company, said the proposed site has the capacity for six reactor units. The company said it is planning to build Westinghouse AP1000 units, but Westinghouse has not confirmed this or released any information about the project. Westinghouse is supplying eight of its AP1000 reactor units for new-build projects, four in the US and four in China – two at Sanmen and two at Haiyang – and says “dozens more” AP1000 plants are planned around the world. These plans may be disrupted by the financial collapses of Toshiba, its parent corporation. (Pittsburgh Post Gazette) Toshiba Corp., told shareholders to expect a multibillion-dollar impairment in Westinghouse’s value. The write-down is expected to be close to $6 billion and it stems from Westinghouse’s acquisition of a nuclear construction company in 2015. Late last month, Toshiba’s president and CEO, Satoshi Tsunakawa, told reporters that Toshiba is likely to exit the nuclear construction business outside of Japan, which would return Westinghouse to its role as a technology designer and service provider. The firm is expected to make a formal announcement in Tokyo on Feb 14. (NucNet) More than 30 GW of nuclear energy facilities will be under construction in China through the next five years with installed capacity of 58 GW by 2020, up 16.5% year on year, according to the country’s 13th Five-Year Plan for energy development, which the National Development and Reform Commission and the National Energy Administration have officially issued. For the targets to be reached China will have to build 7-10 reactors a year. China has 37 reactors in commercial operation, 20 under construction and four that have been approved. Its nuclear share of energy generation was 3.03% in 2015, with a target of 6% by 2020 and 9% by 2030. The country is racing to get rid of its coal fired power plants which are responsible, along with industrial pollution, for significant air quality problems in its major cities. China is also planning to build 30 reactors overseas by 2030. According to statistics quoted by Forbes magazine, Chinese construction costs per MW are about one-third of the Flamanville-3 EPR under construction in northern France. The Yangjiang-1 to Yangjiang-6 reactors in China’s southern province of Guangdong are costing about $1.9bn (€1.7bn) each. (WNN) US policymakers understand the potential impact of losing nuclear plants and states are increasingly recognizing the benefits of nuclear power to consumers, the economy and the environment, Nuclear Energy Institute (NEI) CEO Maria Korsnick said at its annual briefing to Wall Street analysts Nuclear power is the “backbone” of the USA’s electricity system, providing sustained economic benefits, assuring grid reliability and supplying the country’s largest source of low-carbon energy, Korsnick said. The US nuclear fleet provides about 475,000 jobs and produces more than $12 billion annually in federal and state tax revenues, she added. Korsnick identified two challenges of immediate concern to the US nuclear industry: preserving its existing nuclear fleet, and creating policy conditions under which companies will build and develop new nuclear capacity. Nuclear Regulatory Commission (NRC) staff has completed their safety evaluation for a combined license for a proposed nuclear reactor at the North Anna site near Mineral, Virginia. The Final Safety Evaluation Report found no safety aspects that would preclude the issuance of the requested license. The NRC staff will provide the report and the Supplemental Environmental Impact Statement to the Commission for the mandatory hearing phase of the licensing process, which will take place later this year. In the hearing, the Commission will determine if the staff’s review supports the findings required to issue a license. The Commission will then vote on whether to approve the license. Dominion Virginia Power submitted the license application on Nov. 26, 2007 to build an Economic Simplified Boiling Water Reactor (ESBWR) at the North Anna site. The NRC certified the design in 2014. The NRC’s Advisory Committee on Reactor Safeguards independently evaluated the safety aspects of the North Anna application. On Nov. 15, 2016, the committee provided the results of its review to the Commission. The NRC issued an Early Site Permit for North Anna in November 2007, and the agency supplemented the permit’s environmental review for the proposed North Anna reactor in March 2010. However, the utility has not announced plans to actually build the reactors. It joins DTE which also got an NRC license for an ESBWR for its FERMI III reactor near Detroit. The licenses are good for 20 years. (NucNet) UK-based Ultra Electronics has successfully completed acceptance testing of the NuScale power module protection system it is developing for US small modular reactor (SMR) developer NuScale Power. The UK-developed system is a critical safety component and will be fundamental to the operation of NuScale’s SMR technology. Factory acceptance tests were carried out at Ultra’s facility in Dorset, southern England, earlier this month. The tests – witnessed by representatives from the US Nuclear Regulatory Commission (NRC) – successfully demonstrated the systems’ ability to handle safety-critical scenarios associated with the operation of NuScale’s SMR technology. The results of the tests will now form part of the NRC’s review of NuScale’s design certification application. In December 2016, NuScale asked the NRC to review and approve its commercial SMR plant design – the first SMR technology developer to do so. NuScale said the unit will be ready for manufacture and deployment in the US and the UK by the mid-2020s. The first plant has been earmarked for a site at the US Department of Energy’s Idaho National Laboratory. (WNN) Australian and Chinese researchers have made progress in understanding the mechanical properties of a new class of materials for use in molten salt reactors (MSRs). The Australian Nuclear Science and Technology Organization (Ansto) said that NiMo-SiC alloys – prepared from nickel molybdenum metal powders with added silicon carbide particles – have superior corrosion resistance and radiation damage resistance. Although there are no commercial MSRs in operation, there is an MSR and thorium energy research and development program at the Shanghai Institute of Applied Physics (Sinap), with which Antso has a partnership agreement. A number of Ni-MoSiC alloy specimens containing varying amounts of silicon carbide were prepared in Sinap laboratories before being characterized at Antso. “Structural materials for MSRs must demonstrate strength at high temperatures, be radiation resistant and also withstand corrosion,” Antso said. In a paper published in Materials and Design, researchers from the two organizations reported that NiMo-SiC alloys “possess superior mechanical properties owing to the precipitation, dispersion and solid-solution strengthening of the NiMo matrix.” (IEEE Spectrum) An ongoing operation to learn more about the melted nuclear fuel at the crippled Fukushima Daiichi nuclear plant in Japan may have helped the decommissioning project—estimated to take up to 40 years—reach an important milestone. Tokyo Electric Power Company (TEPCO), the plant operator, said that a complicated maneuver employing a 10.5-meter-long telescopic rod with a pan-tilt camera attached has yielded images of a dark mass of rubble inside the containment vessel and under the reactor vessel that houses the nuclear fuel. The images are now being analyzed in an effort to ascertain what the material might be. “If the mass captured on camera is melted nuclear fuel, it would be a big step in helping the decommissioning work,” Yoshiyuki Ishizaki, executive vice president of TEPCO, said on 30 January, following the discovery. Should the presence of nuclear fuel be confirmed, nuclear engineers could then work up a strategy for removing the highly radioactive rubble. However, if the material proves to be part of the damaged pressure vessel, or remains of cables or pipes, then more robot-aided searches of the surrounding area—including the concrete base supporting the containment vessel—will be required.


Home > Press > Metamaterial: Mail armor inspires physicists: KIT researchers reverse hall coefficient -- medieval mail armor inspired development of metamaterial with novel properties Abstract: The Middle Ages certainly were far from being science-friendly: Whoever looked for new findings off the beaten track faced the threat of being burned at the stake. Hence, the contribution of this era to technical progress is deemed to be rather small. Scientists of Karlsruhe Institute of Technology (KIT), however, were inspired by medieval mail armor when producing a new metamaterial with novel properties. They succeeded in reversing the Hall coefficient of a material. The Hall effect is the occurrence of a transverse electric voltage across an electric conductor passed by current flow, if this conductor is located in a magnetic field. This effect is a basic phenomenon of physics and allows to measure the strength of magnetic fields. It is the basis of magnetic speed sensors in cars or compasses in smartphones. Apart from measuring magnetic fields, the Hall effect can also be used to characterize metals and semiconductors and in particular to determine charge carrier density of the material. The sign of the measured Hall voltage allows conclusions to be drawn as to whether charge carriers in the semiconductor element carry positive or negative charge. Mathematicians already predicted theoretically that it is possible to reverse the Hall coefficient of a material (such as gold or silicon), i.e. to reverse its sign. This was expected to be achieved by a three-dimensional ring structure resembling medieval mail armor. How-ever, this was considered difficult, as the ring mesh of millionths of a meter in size would have to be composed of three different components. Christian Kern, Muamer Kadic, and Martin Wegener of KIT's Institute of Applied Physics now found that a single basic material is sufficient, provided that the ring structure chosen follows a certain geometric arrangement. First, they produced polymer scaffolds with a highest-resolution 3D printer. Then, they coated these scaffolds with semiconducting zinc oxide. The result of the experiment: The scientists can produce meta-materials with a positive coefficient, even though their components have negative coefficients. This sounds a bit like the philosopher's stone, the formula, by means of which medieval alchemists tried to convert one substance into another. But here, no conversion takes place. "The charge carriers in the metamaterial remain negatively charged electrons," Christian Kern explains. "Hall measurements only make them appear positively charged, as the structure forces them to take detours." Kern admits that this discovery so far is of no practical use. There are sufficient solids with both negative and positive Hall coefficients. But Kern wants to continue research. The next step will be the production of anisotropic structures with a Hall voltage in the direction of the magnetic field. Normally, Hall voltage is directed vertically to current and magnetic fields. Such unconventional materials might be applied in novel sensors for the direct measurement of magnetic field eddies. About Karlsruhe Institute of Technology (KIT) Karlsruhe Institute of Technology (KIT) pools its three core tasks of research, higher education, and innovation in a mission. With about 9,300 employees and 25,000 students, KIT is one of the big institutions of research and higher education in natural sciences and engineering in Europe. KIT - The Research University in the Helmholtz Association Since 2010, the KIT has been certified as a family-friendly university. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | February 15, 2017
Site: www.eurekalert.org

The Middle Ages certainly were far from being science-friendly: Whoever looked for new findings off the beaten track faced the threat of being burned at the stake. Hence, the contribution of this era to technical progress is deemed to be rather small. Scientists of Karlsruhe Institute of Technology (KIT), however, were inspired by medieval mail armor when producing a new metamaterial with novel properties. They succeeded in reversing the Hall coefficient of a material. The Hall effect is the occurrence of a transverse electric voltage across an electric conductor passed by current flow, if this conductor is located in a magnetic field. This effect is a basic phenomenon of physics and allows to measure the strength of magnetic fields. It is the basis of magnetic speed sensors in cars or compasses in smartphones. Apart from measuring magnetic fields, the Hall effect can also be used to characterize metals and semiconductors and in particular to determine charge carrier density of the material. The sign of the measured Hall voltage allows conclusions to be drawn as to whether charge carriers in the semiconductor element carry positive or negative charge. Mathematicians already predicted theoretically that it is possible to reverse the Hall coefficient of a material (such as gold or silicon), i.e. to reverse its sign. This was expected to be achieved by a three-dimensional ring structure resembling medieval mail armor. How-ever, this was considered difficult, as the ring mesh of millionths of a meter in size would have to be composed of three different components. Christian Kern, Muamer Kadic, and Martin Wegener of KIT's Institute of Applied Physics now found that a single basic material is sufficient, provided that the ring structure chosen follows a certain geometric arrangement. First, they produced polymer scaffolds with a highest-resolution 3D printer. Then, they coated these scaffolds with semiconducting zinc oxide. The result of the experiment: The scientists can produce meta-materials with a positive coefficient, even though their components have negative coefficients. This sounds a bit like the philosopher's stone, the formula, by means of which medieval alchemists tried to convert one substance into another. But here, no conversion takes place. "The charge carriers in the metamaterial remain negatively charged electrons," Christian Kern explains. "Hall measurements only make them appear positively charged, as the structure forces them to take detours." Kern admits that this discovery so far is of no practical use. There are sufficient solids with both negative and positive Hall coefficients. But Kern wants to continue research. The next step will be the production of anisotropic structures with a Hall voltage in the direction of the magnetic field. Normally, Hall voltage is directed vertically to current and magnetic fields. Such unconventional materials might be applied in novel sensors for the direct measurement of magnetic field eddies. For further information, please contact: Dr. Felix Mescoli, Press Officer, Phone: +49 721 608 48120, Fax: +49 721 608 43658, Email: felix.mescoli@kit.edu Karlsruhe Institute of Technology (KIT) pools its three core tasks of research, higher education, and innovation in a mission. With about 9,300 employees and 25,000 students, KIT is one of the big institutions of research and higher education in natural sciences and engineering in Europe. KIT - The Research University in the Helmholtz Association Since 2010, the KIT has been certified as a family-friendly university. This press release is available on the internet at http://www. .


News Article | February 17, 2017
Site: www.cemag.us

The Middle Ages certainly were far from being science-friendly: Whoever looked for new findings off the beaten track faced the threat of being burned at the stake. Hence, the contribution of this era to technical progress is deemed to be rather small. Scientists of Karlsruhe Institute of Technology (KIT), however, were inspired by medieval mail armor when producing a new metamaterial with novel properties. They succeeded in reversing the Hall coefficient of a material. The Hall effect is the occurrence of a transverse electric voltage across an electric conductor passed by current flow, if this conductor is located in a magnetic field. This effect is a basic phenomenon of physics and allows to measure the strength of magnetic fields. It is the basis of magnetic speed sensors in cars or compasses in smartphones. Apart from measuring magnetic fields, the Hall effect can also be used to characterize metals and semiconductors and in particular to determine charge carrier density of the material. The sign of the measured Hall voltage allows conclusions to be drawn as to whether charge carriers in the semiconductor element carry positive or negative charge. Mathematicians already predicted theoretically that it is possible to reverse the Hall coefficient of a material (such as gold or silicon), i.e. to reverse its sign. This was expected to be achieved by a three-dimensional ring structure resembling medieval mail armor. How-ever, this was considered difficult, as the ring mesh of millionths of a meter in size would have to be composed of three different components. Christian Kern, Muamer Kadic, and Martin Wegener of KIT’s Institute of Applied Physics now found that a single basic material is sufficient, provided that the ring structure chosen follows a certain geometric arrangement. First, they produced polymer scaffolds with a highest-resolution 3D printer. Then, they coated these scaffolds with semiconducting zinc oxide. The result of the experiment: The scientists can produce meta-materials with a positive coefficient, even though their components have negative coefficients. This sounds a bit like the philosopher’s stone, the formula, by means of which medieval alchemists tried to convert one substance into another. But here, no conversion takes place. “The charge carriers in the metamaterial remain negatively charged electrons,” Kern explains. “Hall measurements only make them appear positively charged, as the structure forces them to take detours.” Kern admits that this discovery so far is of no practical use. There are sufficient solids with both negative and positive Hall coefficients. But Kern wants to continue research. The next step will be the production of anisotropic structures with a Hall voltage in the direction of the magnetic field. Normally, Hall voltage is directed vertically to current and magnetic fields. Such unconventional materials might be applied in novel sensors for the direct measurement of magnetic field eddies.


News Article | March 3, 2017
Site: www.materialstoday.com

Inspired by medieval mail armor, scientists at Karlsruhe Institute of Technology (KIT) in Germany have produced a new metamaterial with novel properties. As the scientists report in a paper in Physical Review Letters, they succeeded in reversing the component material’s Hall coefficient. The Hall effect describes the production of an electric voltage across an electric conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current. This effect is a basic phenomenon of physics and allows scientists to measure the strength of magnetic fields. It is the basis of magnetic speed sensors in cars or compasses in smartphones. In addition to measuring magnetic fields, the Hall effect can also be used to characterize metals and semiconductors, and in particular to determine a material’s charge carrier density. The sign of the measured Hall voltage allows scientists to determine whether the charge carriers in a semiconductor carry a positive or negative charge. Mathematicians had already predicted that it should theoretically be possible to reverse the Hall coefficient of a material (such as gold or silicon), i.e. to reverse its sign, if the material is fabricated as a three-dimensional ring structure resembling medieval mail armor. However, such a structure was considered difficult to make, as the microscale ring mesh would have to be composed of three different components. Christian Kern, Muamer Kadic and Martin Wegener at KIT’s Institute of Applied Physics have now found that a single material is sufficient, as long as the ring structure follows a certain geometric arrangement. To produce such a structure, the scientists fabricated polymer scaffolds using a high-resolution 3D printer, and then coated these scaffolds with semiconducting zinc oxide. In this way, the scientists were able to produce meta-materials with a positive coefficient, even though their components had negative coefficients. “The charge carriers in the metamaterial remain negatively charged electrons,” Kern explains. “Hall measurements only make them appear positively charged, as the structure forces them to take detours.” Kern admits that this discovery so far has little practical use; there are already sufficient solids with both negative and positive Hall coefficients. But Kern wants to continue this research. The next step will be to produce anisotropic structures with a Hall voltage in the same direction as the magnetic field. Normally, the Hall voltage is directed vertically to the electric and magnetic fields. Such unconventional materials might be applied in novel sensors for the direct measurement of magnetic field eddies. This story is adapted from material from Karlsruhe Institute of Technology, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.


Goychuk I.,University of Potsdam | Kharchenko V.O.,Institute of Applied Physics
Physical Review Letters | Year: 2014

Normal diffusion in corrugated potentials with spatially uncorrelated Gaussian energy disorder famously explains the origin of non-Arrhenius exp[-σ2/(kBT2)] temperature dependence in disordered systems. Here we show that unbiased diffusion remains asymptotically normal also in the presence of spatial correlations decaying to zero. However, because of a temporal lack of self-averaging, transient subdiffusion emerges on the mesoscale, and it can readily reach macroscale even for moderately strong disorder fluctuations of σ∼4-5kBT. Because of its nonergodic origin, such subdiffusion exhibits a large scatter in single-trajectory averages. However, at odds with intuition, it occurs essentially faster than one expects from the normal diffusion in the absence of correlations. We apply these results to diffusion of regulatory proteins on DNA molecules and predict that such diffusion should be anomalous, but much faster than earlier expected on a typical length of genes for a realistic energy disorder of several room kBT, or merely 0.05-0.075eV. © 2014 American Physical Society.


News Article | February 15, 2017
Site: phys.org

The discovery is significant for understanding physical, biological and chemical processes involved in drug design, functions and synthesis of macromolecules, and may even provide clues in the prevention of Alzheimer's disease. Fundamentally, the findings may potentially change the traditional view of the interactions between biomolecules with metal cations. This research outcome, recently published in Physical Review Letters, is part of an international collaboration between ANSTO's Australian Centre for Neutron Scattering (ACNS) and the research group for interfacial water at Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Sciences, Shanghai, China. Generally, in solution with many multivalent transition-metal ions, such as Cu2+, Pt2+, Pd2+, and Co3+, the solubility of aromatic amino acids decreases significantly because most of them will form complex precipitates with the ions, as documented in standard chemistry and biochemistry reference works. However, considerably increased solubility of tryptophan (Trp) in a CuCl2 aqueous solution has been observed experimentally and predicted theoretically by the research group led by Professor Haiping Fang at SIAP. This unusual phenomenon can only be observed under a special condition of high local concentration of Cu2+ at the surface of Trp. Fundamentally, it is attributed to the strong interaction between Cu2+ and the aromatic ring in Trp, referred to as the cation-pi interaction. Co-authors Dr Dehong Yu and Dr Richard Mole carried out measurements using quasi elastic neutron scattering (QENS) on the Pelican instrument at ACNS. The experiment provides direct evidence of the strong cation-pi interaction responsible for the enhanced solubility of Trp in a CuCl2 aqueous solution. QENS exploits small energy exchanges between the diffusing particles and scattered neutrons, which is directly related to the diffusive processes taking place in the system. The self-diffusion coefficient of the system can be obtained from the QENS measurement. The significant difference in diffusion coefficients between tryptophan with and without Cu2+ suggested that the tryptophan complex containing Cu2+ moved much more slowly than the tryptophan without Cu2+. This observation supports the theoretical prediction of the enhancement of water affinity due to the presence of Cu2+. "In this experiment we make full use of the QENS capability of the Pelican instrument and the high sensitivity of neutrons to hydrogen atoms to study Trp dynamics under different environments, as the QENS signal from the entire system is dominated by the hydrogen atoms in tryptophan," said Yu. Explore further: Pelican instrument provides crucial experimental evidence of unusual quantum state More information: Guosheng Shi et al. Unexpectedly Enhanced Solubility of Aromatic Amino Acids and Peptides in an Aqueous Solution of Divalent Transition-Metal Cations, Physical Review Letters (2016). DOI: 10.1103/PhysRevLett.117.238102


Demekhov A.G.,Institute of Applied Physics
Space Science Reviews | Year: 2012

We discuss the electromagnetic processes in the ULF range which are important for the coupling between the atmosphere, ionosphere, and magnetosphere (AIM). The main attention is given to the Pc1-2 frequency ranges (f≈0.1-10 Hz) where some natural resonances in the AIM system are located. In particular, we consider the resonant structures in the spectra of the magnetic background noise related to the Alfvén resonances in the ionosphere as a possible diagnostic tool for studies of the ionospheric parameters. We also discuss the self-excitation of Alfvén waves in the ionosphere due to the AIM coupling and the role of such waves in the acceleration of electrons in the upper ionosphere and magnetosphere. Precipitation of magnetospheric ions due to their interaction with the ion-cyclotron waves is analyzed in relation to the ionospheric current systems, formation of partial ring current, and the influence of the ionosphere-magnetosphere feedback on the generation of such waves. © 2011 Springer Science+Business Media B.V.


Home > Press > Sorting machine for atoms:Researchers at the University of Bonn clear a further hurdle on the path to creating quantum computers Abstract: Physicists at the University of Bonn have cleared a further hurdle on the path to creating quantum computers: in a recent study, they present a method with which they can very quickly and precisely sort large numbers of atoms. The work has now been published in Physical Review Letters. Imagine you are standing in a grocery store buying apple juice. Unfortunately, all of the crates are half empty because other customers have removed individual bottles at random. So you carefully fill your crate bottle by bottle. But wait: The neighboring crate is filled in exactly the opposite way! It has bottles where your crate has gaps. If you could lift these bottles in one hit and place them in your crate, it would be full straight away. You could save yourself a lot of work. Unfortunately, such solutions don't (yet) exist for half-empty drinks crates. However, physicists at the University of Bonn want to sort thousands of atoms however they like in the future in this way - and in a matter of seconds. Around the world, scientists are currently looking for methods that enable sorting processes in the microcosm. The proposal by Bonn-based researchers could push the development of future quantum computers a crucial step forward. This allows atoms to interact with each other in a targeted manner in order to be able to exploit quantum-mechanical effects for calculations. In addition, the particles have to be brought into spatial proximity with one another. Magnetized atoms on optical conveyor belts The physicists are using a special property of atoms to create their sorting machine: These rotate around their own axis like little spinning tops. The direction of rotation -- the spin -- can be influenced with microwaves. The physicists thus initially set all of the atoms off in the same direction of rotation in their experiment. In this state, it was possible to load the particles onto a laser beam. However, beforehand, they had to manipulate the laser in such a way that it matched the spin of its particles -- a process known as polarization. The atoms were then held by the polarized laser beam in such a manner that they were unable to move. Every particle occupies a particular place on the laser beam -- similar to the bottles in the crate. However, like in the drinks crate, some of the places in the laser beam are also unoccupied. "We thus reversed the direction of rotation in a very targeted manner for individual atoms," explains Dr. Andrea Alberti, the team leader at the Institute of Applied Physics of the University of Bonn. "These particles were then no longer captured by our laser beam. However, we were able to grab them with a second, differently polarized laser beam and thus move them as desired. The transport beam can, in principle, move as many atoms as one likes at the same time. As this takes place, they retain their position to each other. As in the example with the bottles, several particles can thus be lifted at once and placed in the gaps between other atoms in one go. "Our sorting method is thus extremely efficient," explains the lead author of the study, Carsten Robens. "It does not make any major difference whether we are sorting hundreds or thousands of atoms - the time needed only increases slightly." For the moment, the researchers only worked with four atoms in their experiment, which is now being published. In principle, the method is suitable for creating any atom pattern. This makes it interesting for solid-state physicists, for instance, to investigate the behavior of semiconductor crystals under certain conditions. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | February 13, 2017
Site: www.cemag.us

Physicists at the University of Bonn have cleared a further hurdle on the path to creating quantum computers: in a recent study, they present a method with which they can very quickly and precisely sort large numbers of atoms. The work has now been published in Physical Review Letters. Imagine you are standing in a grocery store buying apple juice. Unfortunately, all of the crates are half empty because other customers have removed individual bottles at random. So you carefully fill your crate bottle by bottle. But wait: The neighboring crate is filled in exactly the opposite way! It has bottles where your crate has gaps. If you could lift these bottles in one hit and place them in your crate, it would be full straight away. You could save yourself a lot of work. Unfortunately, such solutions don’t (yet) exist for half-empty drinks crates. However, physicists at the University of Bonn want to sort thousands of atoms however they like in the future in this way — and in a matter of seconds. Around the world, scientists are currently looking for methods that enable sorting processes in the microcosm. The proposal by Bonn-based researchers could push the development of future quantum computers a crucial step forward. This allows atoms to interact with each other in a targeted manner in order to be able to exploit quantum-mechanical effects for calculations. In addition, the particles have to be brought into spatial proximity with one another. The physicists are using a special property of atoms to create their sorting machine: These rotate around their own axis like little spinning tops. The direction of rotation — the spin — can be influenced with microwaves. The physicists thus initially set all of the atoms off in the same direction of rotation in their experiment. In this state, it was possible to load the particles onto a laser beam. However, beforehand, they had to manipulate the laser in such a way that it matched the spin of its particles — a process known as polarization. The atoms were then held by the polarized laser beam in such a manner that they were unable to move. Every particle occupies a particular place on the laser beam — similar to the bottles in the crate. However, like in the drinks crate, some of the places in the laser beam are also unoccupied. “We thus reversed the direction of rotation in a very targeted manner for individual atoms,” explains Dr. Andrea Alberti, the team leader at the Institute of Applied Physics of the University of Bonn. “These particles were then no longer captured by our laser beam. However, we were able to grab them with a second, differently polarized laser beam and thus move them as desired. The transport beam can, in principle, move as many atoms as one likes at the same time. As this takes place, they retain their position to each other. As in the example with the bottles, several particles can thus be lifted at once and placed in the gaps between other atoms in one go. “Our sorting method is thus extremely efficient,” explains the lead author of the study, Carsten Robens. “It does not make any major difference whether we are sorting hundreds or thousands of atoms — the time needed only increases slightly.” For the moment, the researchers only worked with four atoms in their experiment, which is now being published. In principle, the method is suitable for creating any atom pattern. This makes it interesting for solid-state physicists, for instance, to investigate the behavior of semiconductor crystals under certain conditions.

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