#Scientists paint quantum electronics with beams of light: Chance effect of lab's fluorescent lights leads to discovery In contrast to using advanced nanofabrication facilities based on chemical processing of materials,
this flexible technique allows for rewritable'optical fabrication'of devices. This finding is likely to spawn new developments in emerging technologies such as low-power electronics based on the spin of electrons or ultrafast quantum computers.
The research is published today in the American Association for the Advancement of Science's new online journal Science Advances,
where it is featured on the journal's front page.""This observation came as a complete surprise,
"said David D. Awschalom, Liew Family Professor and deputy director in the Institute of Molecular Engineering at UCHICAGO,
and one of two lead researchers on the project.""It's one of those rare moments in experimental science where a seemingly random event--turning on the room lights--generated unexpected effects with potentially important impacts in science and technology."
"The electrons in topological insulators have unique quantum properties that many scientists believe will be useful for developing spin-based electronics and quantum computers.
However, making even the simplest experimental circuits with these materials has proved difficult because traditional semiconductor engineering techniques tend to destroy their fragile quantum properties.
Even a brief exposure to air can reduce their quality. In Science Advances, the researchers report the discovery of an optical effect that allows them to"tune"the energy of electrons in these materials using light,
and without ever having to touch the material itself. They have used it to draw and erase p-n junctions--one of the central components of a transistor--in a topological insulator for the first time.
Like many advances in science, the path to this discovery had unexpected an twist.""To be honest,
"said Andrew Yeats, a graduate student in Awschalom's laboratory and the paper's lead author."
and their room lights happened to emit at just the right wavelength. The electric field from the polarized strontium titanate was leaking into the topological insulator layer,
changing its electronic properties. Awschalom and his colleagues found that by intentionally focusing beams of light on their samples,
the team measured their samples in high magnetic fields. They found promising signatures of an effect called weak anti-localization,
"One exciting aspect of this work is that it's noninvasive"said Nitin Samarth, Professor and Downsbrough Head of Physics at Penn State,
"In a way, the most exciting aspect of this work is that it should be applicable to a wide range of nanoscale materials such as complex oxides, graphene,
and transition metal dichalcogenides,"said Awschalom.""It's not just that it's faster and easier.
#Single atom alloy platinum-copper catalysts cut costs, boost green technology: New generation of catalysts demonstrated for selective hydrogenation of butadiene Abstract:
A new generation of platinum-copper catalysts that require very low concentrations of platinum in the form of individual atoms to cleanly
and cheaply perform important chemical reactions is reported today by Tufts University researchers in the journal Nature Communications.
Platinum is used as a catalyst in fuel cells, in automobile converters and in the chemical industry because of its remarkable ability to facilitate a wide range of chemical reactions.
However, its future potential uses are limited significantly by scarcity and cost, as well as the fact that platinum readily binds with carbon monoxide,
which"poisons"the desired reactions, for example in polymer electrolyte membrane (PEM) fuel cells, which are the leading contenders for small-scale and mobile power generation not based on batteries or combustion engines.
The Tufts researchers discovered that dispersing individual, isolated platinum atoms in much less costly copper surfaces can create a highly effective
and cost-efficient catalyst for the selective hydrogenation of 1, 3 butadiene, a chemical produced by steam cracking of naphtha or by catalytic cracking of gas oil.
in order to facilitate downstream polymer production. The current industrial catalyst for butadiene hydrogenation uses palladium and silver.
while a relatively cheap metal, is not nearly as catalytically powerful as platinum, noted Professor of Chemistry Charles Sykes, Ph d.,one of the senior authors on the paper."
"The researchers first conducted surface science experiments to study precisely how platinum and copper metals mix."
"We were excited to find that the platinum metal dissolved in copper, just like sugar in hot coffee, all the way down to single atoms.
We call such materials single atom alloys, "said Sykes. The Tufts chemists used a specialized low temperature scanning tunneling microscope to visualize the single platinum atoms and their interaction with hydrogen."
With that knowledge, Sykes and his fellow chemists turned to long-time Tufts collaborator Maria Flytzani-Stephanopoulos, Ph d.,the Robert and Marcy Haber Endowed Professor in Energy Sustainability at the School of engineering,
They synthesized small quantities of realistic catalysts, such as platinum-copper single atom alloy nanoparticles supported on an alumina substrate,
and then tested them under industrial pressure and temperatures.""To our delight, these catalysts worked very well
and their performance was steady for many days, "said Flytzani-Stephanopoulos.""While we had shown previously that palladium would do related reactions in a closed reactor system,
this work with platinum is our first demonstration of operation in a flow reactor at industrially relevant conditions.
We believe this approach is also applicable to other precious metals if added as minority components in copper."
"Further, the researchers found that the reaction actually became less efficient when they used more platinum,
"Environmental Benefits Because platinum is at the center of many clean energy and green chemicals production technologies, such as fuel cells, catalytic converters,
and value-added chemicals from bio-renewable feedstocks, the new, less expensive platinum-copper catalysts could facilitate broader adoption of such environmentally friendly devices and processes,
The work is the latest fruit from a long cross-disciplinary partnership between Sykes and Flytzani-Stephanopoulos."
In the early 2000s, Maria's group had pioneered the single-atom approach for metals anchored on oxide supports as the exclusive active sites for the water-gas shift reaction to upgrade hydrogen streams for fuel cell use.
Together we embarked on a new direction involving single atom alloys as catalysts for selective hydrogenation reactions.
"Sykes and Flytzani-Stephanopoulos have used this approach to design a variety of single atom alloy catalysts that have,
and properties of single atom alloy surfaces and then applied this knowledge to develop a working catalyst.
Armed with this knowledge, we are now ready to compare the stability of these single atom alloy catalysts to single atom catalysts supported on various oxide or carbon surfaces.
#Dielectric film has refractive index close to air The refractive indices of naturally occurring materials are limited, and there exists an index gap between indices of air and available solid materials.
With many photonics and electronics applications, there has been considerable effort in creating artificial materials with optical and dielectric properties similar to air
Here we demonstrate a class of ordered nanolattice materials consisting of periodic thin-shell structures with near-unity refractive index and high stiffness.
Using a combination of three-dimensional nanolithography and atomic layer deposition these ordered nanostructured material have reduced optical scattering
and improved mechanical stability compared to existing randomly porous materials. Using Zno and Al2o3 as the building materials,
refractive indices from 1. 3 down to 1. 025 were achieved. The experimental data can be described accurately by Maxwell-Garnett effective media theory,
which can provide a guide for index design. The demonstrated low-index, low-scattering, and high-stiffness materials can serve as high-quality optical films in multilayer photonic structures, waveguides, resonators,
and ultra-low-k dielectrics. Researchers from North carolina State university have developed a dielectric film that has optical and electrical properties similar to air
but is strong enough to be incorporated into electronic and photonic devices-making them both more efficient and more mechanically stable.
At issue is called something refractive index, which measures how much light bends when it moves through a substance.
Air, for example, has a refractive index of 1, while water has a refractive index of 1. 33
-which is why a straw appears to bend when you put it in a glass of water.
Photonic devices require a high contrast between its component materials, with some components having a high refractive index
and others have a low one. The higher the contrast between those materials the more efficient the photonic device is
Air has the lowest refractive index, but it isn't mechanically stable. And the lowest refractive index found in solid,
naturally occurring materials is 1. 39. But now researchers have developed a film made of aluminum oxide that has a refractive index as low as 1. 025 but that is mechanically stiff."
"By manipulating the structure of the aluminum oxide, which is dielectric, we've improved both its optical and mechanical properties,
"says Chih-Hao Chang, corresponding author of a paper on the work and an assistant professor of mechanical and aerospace engineering at NC State.
Dielectrics are insulator materials that are used in an enormous array of consumer products. For example, every handheld device has hundreds of capacitors,
which are dielectric components that can store and manage electric charge.""The key to the film's performance is ordered the highly spacing of the pores,
which gives it a more mechanically robust structure without impairing the refractive index, "says Xu Zhang,
lead author of the paper and a Ph d. student at NC State. The researchers make the film by first using a nanolithography developed in Chang's lab to create highly-ordered pores in a polymer substrate.
That porous polymer then serves as a template, which the researchers coats with a thin layer of aluminum oxide using atomic layer deposition.
The polymer is burned then off leaving behind a three-dimensional aluminum oxide coating.""We are able to control the thickness of the aluminum oxide,
creating a coating between two nanometers and 20 nanometers thick, "Zhang says.""Using zinc oxide in the same process,
we can create a thicker coating. And the thickness of the coating controls and allows us to design the refractive index of the film."
"Regardless of the how thick the coating is, the film itself is approximately one micrometer thick."
"The steps in the process are potentially scalable, and are compatible with existing chip manufacturing processes,
"Chang says.""Our next steps include integrating these materials into functional optical and electronic devices
#Researchers from Kiel and Bochum develop new information storage device Scientists from Kiel University and the Ruhr Universität Bochum (RUB) have developed a new way to store information that uses ions to save data
and electrons to read data. This could enable the size of storage cells to be reduced to atomic dimensions.
But that is not the only advantage of the new technology, as the researchers reported in the journal Scientific Reports."
"Six plus seven makes three-plus one carried over",calculated Professor Hermann Kohlstedt, Head of the Nanoelectronic group at Kiel University.
This describes that storing information in the short or long term is important-even for the simplest calculations.
Modern computers use this principle in practically Every bit (unit of measurement for the digital information content) and the almost unbelievable increase in performance over the last decade was based on a very simple rule:
faster processors and more storage space. Standard memory devices are based on electrons which are displaced by applying voltage.
The development of ever smaller and more energy-efficient storage devices according to this principle, however, is increasingly approaching its limits:
because there is not just one storage device in our computers, but several optimised ones, depending on the task."
"Moving data between individual storage devices has begun now to take a not inconsiderable amount of time. Put simply:
more is moved backwards and forwards than is calculated",said Kohlstedt. That is why industrial companies and research institutes around the world are working on a more efficient, universal storage device that combines the advantages of all storage devices and moves as little data as possible back and forth.
In order to do so, researchers want to move away from charge-based storage and towards the type
which is based on electrical resistance. A component just like this has now come from the labs in Kiel and Bochum.
It consists of two metallic electrodes that are separated by a so-called solid ion conductor usually a transition metal oxide.
If a voltage is applied then, the ohmic resistance of the storage cell changes. This is caused by oxidation
and reduction processes on the electrodes, as well as ions within the layer between being displaced. The advantage is that cells that are constructed in this way are easy to produce
and can be reduced to almost the size of atoms. The scientists achieve a long storage time by setting the ion density in the cells precisely via the voltage applied."
which was only a few nanometres (a millionth of a millimetre) thin to utilise quantum-mechanical effects for the flow through the storage cells."
"The tunnel effect enables us to move electrons through the ultra-thin layer with very little energy,
This way, ions can be used specifically for storing and electrons specifically for reading data. The researchers also reported that their research had another very interesting element.
The new resistance-based storage devices could even simulate brain structures. Rapid pattern recognition and a low energy consumption in connection with enormous parallel data processing would enable revolutionary computer architectures."
"This opens up a massive area for innovations in combination with terms like Industry 4. 0, in which autonomous robots work,
or cars which drive themselves and are out on our roads, "said Professor Hermann Kohlstedt and his colleague from Bochum,
Dr Thomas Mussenbrock to describe the research results. They are both working on developing artificial neural networks in the'FOR 2093'researcher group u
#Chalmers researchers extend the lifetime of atoms using a mirror: In an experiment researchers at Chalmers University of Technology have got an artificial atom to survive ten times longer than normal by positioning the atom in front of a mirror.
The findings were recently publish If one adds energy to an atom-one says that the atom is excited--it normally takes some time before the atom loses energy and returns to its original state.
This time is called the lifetime of the atom. Researchers at Chalmers University of Technology have placed an artificial atom at a specific distance in front of a short circuit that acts as a mirror.
By changing the distance to the mirror they can get the atom to live longer,
The artificial atom is actually a superconducting electrical circuit that the researchers make behave as an atom.
Just like a natural atom, you can charge it with energy; excite the atom; which it then emits in the form of light particles.
and in reality is microwaves.""We have demonstrated how we can control the lifetime of an atom in a very simple way,
"says Per Delsing, Professor of Physics and leader of the research team.""We can vary the lifetime of the atom by changing the distance between the atom and the mirror.
is that it sees the very small variations in the electromagnetic field which must exist due to quantum theory,
known as vacuum fluctuations,"says Göran Johansson, Professor of Theoretical and Applied Quantum physics and leader of the theory group.
The system that the Chalmers researchers succeeded in building is suited particularly well for measuring the vacuum fluctuations
#Production of Injectable Nanocomposite Paste in Iran Abstract: Iranian researchers from Materials and Energy Research center (MERC) succeeded in the production of a type of biocompatible nanocomposite with the ability to carry drugs,
which can be injected into damaged bones. After the completion of tests and being mass-produced, the product can be used in orthopedic surgeries to recover
and cure bones damaged due to tumors, cysts or fractures. The use of bone replacement in various forms has increased in recent years.
Injectable pastes are samples of the replacements used in tissue engineering. According to the researchers, the aim of the research was to prepare an injectable paste made of bioglass and sodium alginate polymer with biocompatibility properties.
Injectable pastes should be designed in a way that they can be injected by imposing acceptable force without phase separation between the powder and the liquid.
The injected paste can stay in the implant area without moving or being washed by water.
In addition, the product is able to form hydroxyapatite nanoparticles to create chemical bonds with bone tissue in the body.
Results of the research have been published in Journal of the Australian Ceramics Society vol. 51, issue 2, 2015, pp. 99-108 8
#What are these nanostars in 2-D superconductor supposed to mean? Physicists from France and Russia have discovered magnetic disturbances in 2d superconductor layer,
resembling little oscillating stars. These starlike excitations are caused by a single magnetic atom put into the layer of superconducting material.
the observed effect looks like magnetic"nanostars in the superconducting univers";"building constellations of them can be used in quantum electronics.
Physicists from France and Russia have discovered that the magnetic atoms in a two-dimensional layered superconductor create electronic disturbances that look like oscillating"nanostars".
"A"constellation"of these disturbances could be used in quantum electronics. The results of the study have been published in the prestigious scientific journal Nature Physics.
Prof. Dmitri Roditchev from the Superior School of Industrial Physics and Chemistry (ESPCI Paristech, Paris), Gerbold Ménard, Dr. Christophe Brun, Dr. Tristan Cren from the Institute of Nanosciences
of Paris at Sorbonne University, Dr. Vasily Stolyarov from the Laboratory of Topological Quantum Phenomena in Superconducting Systems at MIPT,
and their colleagues from Paris-Saclay University studied the emergence of Yu-Shiba-Rusinov (YSR) states bound around single magnetic atoms embedded in a two-dimensional superconductor.
YSR states were predicted theoretically in the 1960s but very few evidences for them have been revealed experimentally till now.
In the present work it was found that in two-dimensional systems, magnetic excitations extend over a greater distance as compared to ordinary three-dimensional superconductors,
and the emergent YSR quantum states are more stable, which makes them more suitable for developing a new generation of quantum electronics.
A crystal lattice of a layered superconducting material-niobium diselenide-was used in the tests. With an ultra-low-temperature scanning tunnelling microscope built by Roditchev,
"We have demonstrated that the use of two-dimensional superconductors instead of the three dimensional ones results in an increase in the spatial extension of YSR states for several dozen nanometres,
i e. ten times further than in"normal"three-dimensional superconductors. And the area of excitation was shaped like a sixfold electronic"star"with its rays extending along the axis of the crystal lattice of niobium diselenide.
The experiments described in the article were conducted in Paris. Work is underway at MIPT's Laboratory of Topological Quantum Phenomena in Superconducting Systems to create the experimental conditions necessary to obtain such high quality results.
The Laboratory was set up in 2014 using funds from a mega grant awarded to Alexander Golubov, a professor at the University of Twente (Netherlands.
The main purpose of the Laboratory is to study the quantum properties of new superconductors and topologically protected materials,
They suggested that magnetic atoms introduced into a superconductor must create special states of excitation around themselves-electron-hole standing waves named after their discoverers.
For the last 20 years, scientists have been attempting to create quantum systems that will outperform traditional semiconductor-based computers, the development potential
The main problem preventing the development of these computers is the high sensitivity of the nanoworld to external influences that destroy quantum states.
but rather special excitations in two-dimensional quantum systems in a magnetic field. The theory predicts that such non-Abelian anyons may occur in a two-dimensional"liquid"of electrons in a superconductor under the influence of a local magnetic field.
The electron liquid thus becomes degenerate, i e. the electrons can have different states at the same energy level.
The superposition of several anyons cannot be affected without moving them, therefore they are protected completely from disturbances e
EPFL has developed a miniaturized microfluidic device that will allow medical staff to monitor in real time levels of glucose,
or blood serum along with an array of electronics to transmit the results in real time to a tablet via Bluetooth,
This advance will drastically reduce the number of machines cluttered around patients-an obvious practical advantage for the medical staff, not to mention the psychological boon for loved ones.
Discussions are now under way for tests to be carried out at the University Hospital of Lausanne (CHUV.
This progress towards more precise and effective medicine was achieved under the Nano-Tera initiative, which is financed by The swiss government.
#Researchers transform slow emitters into fast light sources Researchers from Brown University, in collaboration with colleagues from Harvard, have developed a new way to control light from phosphorescent emitters at very high speeds.
The technique provides a new approach to modulation that could be useful in all kinds of silicon-based nanoscale devices,
including computer chips and other optoelectronic components.""Our results demonstrate relatively fast modulation from fundamentally slow phosphorescent light emitters,
associate professor of engineering and physics at Brown and senior author of a new paper describing the work."
Phosphors are common light emitters used in light bulbs, LEDS and elsewhere. They are extremely efficient
because much of the energy pumped into them is converted to light as opposed to heat.
But in this latest work, Zia and collaborators, including researchers from Shriram Ramanathan's group at Harvard university,
by rapidly changing the environment around the emitter, "Zia said. The work was led by Sebastien Cueff,
a postdoctoral researcher in Zia's lab. Cueff started with an emitter made of erbium ions,
an important phosphor that is widely used in fiber-optic telecommunication networks. He combined that with a material called vanadium dioxide (VO2.
when pumped with energy, changes very quickly from a transparent insulating state to a reflective metallic state.
This change in reflectivity, in turn, switches how nearby erbium ions emit light. As the VO2 changes phase, the erbium emissions go from being generated mostly by magnetic dipole transitions (the rotational torque push
and pull of magnetic forces), to being generated mostly by electric dipole transitions (the linear push and pull of electric forces).
Those two emission pathways have distinct spectra, and the modulation back and forth between the two can be used as a means to encode information.
One example could be optical communications networks on computer chips. Prototype on-chip networks have used semiconductor lasers as light emitters.
They can modulate very quickly, but they have downsides. Semiconductors can't be grown directly on a silicon chip,
so fabrication can be difficult. Using indirect means of modulation--interferometers, for example--makes for bulky systems that take up a lot of real estate on a chip.
What's more, semiconductor lasers are not particularly efficient. They produce a lot of heat along with light
which is a problem on a silicon chip. Erbium and other phosphors, on the other hand, can be deposited directly on silicon, making fabrication easier.
There's still more work to be done to get such a system up to a speed that would be useful on a chip,
A faster means of changing the VO2 phase--perhaps using electricity instead of a laser--could make the system much faster still.
and industrial researchers working on optoelectronics and nanophotonics, "the researchers write e
#Monitoring critical blood levels in real time in the ICU: EPFL has developed a miniaturized microfluidic device that will allow medical staff to monitor in real time levels of glucose,
lactate a s. o. and react more quickly No larger than a pack of chewing gum, the prototype developed by EPFL's Integrated Systems Laboratory (LSI) is deceptively simple in appearance.
or blood serum along with an array of electronics to transmit the results in real time to a tablet via Bluetooth,
This advance will drastically reduce the number of machines cluttered around patients-an obvious practical advantage for the medical staff, not to mention the psychological boon for loved ones.
Discussions are now under way for tests to be carried out at the University Hospital of Lausanne (CHUV.
This progress towards more precise and effective medicine was achieved under the Nano-Tera initiative, which is financed by The swiss government.
New Option to Diagnose Leukemia Iranian researchers from Tarbiat Modarres University designed a biosensor that enables the early diagnosis of leukemia in the test sample by using naked eyes.
The aim of the research was to design an effective system to diagnose blood cancer (leukemia) by using gold nanobars.
To this end, samples of a nanobiosensor have been designed and their application has been evaluated in the diagnosis of the disease.
The presence of some proteins in biological liquids of humans (blood saliva and urine) with determined concentration can be the sign of dangerous diseases.
Therefore, it is effective to monitor and measure the proteins to diagnose and prevent diseases.
Lysozyme protein has been selected as the target biomolecule in this research. The excess secretion of this protein can be a sign of malfunction in kidney performance
and it may result in leukemia. Diagnosis tests are very time-consuming, expensive and difficult in some cases.
For example, common methods to diagnose lysozyme protein are Turbidity Meter, Lyso-rocket electrophoresis and ELISA.
All of these methods have some problems due to their complication of the process sensitivity, cost, energy loss and human resources.
The system designed in this research is complicated less in comparison with other diagnosis methods, and it is available,
sensitive, cost effective and quick. Results of the research have been published in Talanta, vol. 144,2015, pp. 778-787 7
#Upgrading the quantum computer: New quantum computer architecture Abstract: Within the last several years, considerable progress has been made in developing a quantum computer,
which holds the promise of solving problems a lot more efficiently than a classical computer. Physicists are now able to realize the basic building blocks,
the quantum bits (qubits) in a laboratory, control them and use them for simple computations. For practical application, a particular class of quantum computers, the so-called adiabatic quantum computer, has generated recently a lot of interest among researchers and industry.
It is designed to solve real-world optimization problems conventional computers are not able to tackle. All current approaches for adiabatic quantum computation face the same challenge:
The problem is encoded in the interaction between qubits; to encode a generic problem, an all-to-all connectivity is necessary,
but the locality of the physical quantum bits limits the available interactions.""The programming language of these systems is the individual interaction between each physical qubit.
The possible input is determined by the hardware. This means that all these approaches face a fundamental challenge
when trying to build a fully programmable quantum computer, "explains Wolfgang Lechner from the Institute for Quantum Optics and Quantum Information (IQOQI) at the Austrian Academy of Sciences in Innsbruck.
Theoretical physicists Wolfang Lechner, Philipp Hauke and Peter Zoller have proposed now a completely new approach. The trio, working at the University of Innsbruck and the IQOQI, suggest overcoming the challenges by detaching the logical qubit from the physical implementation.
Each physical qubit corresponds to one pair of logical qubits and can be tuned by local fields.
These could be electrical fields when dealing with atoms and ions or magnetic fields in superconducting qubits."
"Any generic optimization problem can be programmed fully via the fields, "explains co-author Philipp Hauke from the Institute for Theoretical physics at the University of Innsbruck, Austria."
"By using this approach we are not only avoiding the limitations posed by the hardware but we also make the technological implementation scalable."
"Integrated fault tolerance Because of the increased number of degrees of freedom, which could also lead to nonphysical solutions,
the physicists arrange the qubits in a way that four physical qubits interact locally.""In this way we guarantee that only physical solutions are possible,
"With this redundancy our model has also a high fault tolerance, "says Lechner. The new architecture can be realized on various platforms ranging from superconducting circuits to ultracold gases in optical lattices."
"The step from mechanical calculators to fully programmable computers started the information technology age 80 years ago.
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