which use photons instead of electrons to transport and manipulate information, offer many advantages compared to traditional electronic links found in today computers.
The team successfully suspended glass particles 400 nanometres across in a vacuum using an electric field,
where the position or energy of a particle exists in two or more states at the same time and entanglement,
where two particles share the same state (and change in tandem with each other) despite not touching.
We are trying to do the same with glass particles made up of billions of atoms,
During cavity cooling, a particle is suspended by a laser light field contained between two mirrors, which has a very carefully calibrated wavelength.
The laser light can hold the particle steady (a phenomenon known as optical tweezing) and draw motional energy out of it at the same time.
"Our solution was to combine the laser beam that cools the glass particle with an electric field
"The electric field also gently moves the glass particle around inside the laser beam, helping it lose temperature more effectively."
Since the particles currently used in quantum experiments are tiny, they have negligible mass and so barely interact with gravity.
two-dimensional particles embedded within a gel, stimulates bone growth through a complex signaling mechanism without the use of proteins known as growth factors,
Nanosilicate particles are embedded in a collagen-based hydrogel, forming a material that helps trigger bone formation within the body.
magnesium and lithium combined in tiny nanosilicate particles that are 100,000 times thinner than a sheet of paper.
Based on our strong preliminary studies, we predict that these highly biofunctional particles have immense potential to be used in biomedical applications
which strongly effects the propagation of light, in the same way that semiconductors control the flow of electrons.
Sabine van Rijt, CPC/ilbd, Helmholtz Zentrum Mnchen) Nanoparticles are extremely small particles that can be modified for a variety of uses in the medical field.
including irradiation with electrons and ions, but none of them worked. So far, the oxygen plasma approach worked the best,
#New study shows bacteria can use magnetic nanoparticles to create a'natural battery'(Nanowerk News) New research shows bacteria can use tiny magnetic particles to effectively create a'natural battery.'
"the bacteria can load electrons onto and discharge electrons from microscopic particles of magnetite. This discovery holds out the potential of using this mechanism to help clean up environmental pollution,
The flow of electrons is critical to the existence of all life and the fact that magnetite can be considered to be redox active opens up the possibility of bacteria being able to exist
phototrophic iron-oxidizing bacteria removed electrons from the magnetite, thereby discharging it. During the nighttime conditions, the iron-reducing bacteria took over
and were able to dump electrons back onto the magnetite and recharge it for the following cycle.
In principle, they are miniaturized extremely electron storage units. qdots can be produced using the same techniques as normal computer chips.
it is only necessary to miniaturize the structures on the chips until they hold just one single electron (in a conventional PC it is 10 to 100 electrons.
The electron stored in a qdot can take on states that are predicted by quantum theory. However, they are very short-lived:
a photon. Photons are wave packets that vibrate in a specific plane the direction of polarization.
The state of the qdots determines the direction of polarization of the photon.""We used the photon to excite an ion,
"explains Prof. Dr. Michael Khl from the Institute of Physics at the University of Bonn."
"Then we stored the direction of polarization of the photon"."Conscientious ions To do so, the researchers connected a thin glass fiber to the qdot.
They transported the photon via the fiber to the ion many meters away. The fiberoptic networks used in telecommunications operate very similarly.
To make the transfer of information as efficient as possible, they had trapped the ion between two mirrors.
The mirrors bounced the photon back and forth like a ping pong ball, until it was absorbed by the ion."
"In the process, we were able to measure the direction of polarization of the previously absorbed photon".
and more than 500 times faster than phosphorescence-lifetime-based two-photon microscopy (TPM. The results are published March 30 in Nature Methods advanced online publication("High-speed label-free functional photoacoustic microscopy of mouse brain in action".
#A quantum sensor for nanoscale electron transport The word defect doesnt usually have a good connotation--often indicating failure.
Graphic depiction of NV center sensors (red glowing spheres) used to probe electron motion in a conductor.
In this experiment, physicists harness the sensitivity of these isolated quantum systems to characterize electron motion. A conductive silver sample is deposited onto a diamond substrate that contains NV centers.
At temperatures above absolute zero, the electrons inside of the silver layer (or any conductor) bounce around
Since electrons are charged particles, their motion results in fluctuating magnetic fields, which extend outside of the conductor.
which tells them about the electron behavior at a very small length scale. Like any good sensor, the NV centers are almost completely non-invasivetheir read-out with laser light does not disturb the sample they are sensing.
thus electrons travel dont travel very far--roughly 10 nanometers or less--before scattering off an obstacle.
and electrons can travel over 100 times farther. The electron movement, and corresponding magnetic field noise from the single silver crystal is a departure from so-called Ohmic predictions of the polycrystalline case,
and the team was able to explore both of these extremes non-invasively. These results demonstrate that single NV centers can be used to directly study electron behavior inside of a conductive material on the nanometer length scale.
Notably, this technique does not require electrical leads, applied voltages, or even physical contact with the sample of interest,
whether a proton gradient could induce water transport. We were surprised very to find that it could.
He says that osmotic agents often have to be at concentrations exceeding 100 millimolar to drive water movement in forward osmosis nanofiltration. f a proton gradient is used as the driving force instead,
the researchers created a spherical mass of particles, referred to as a nanoparticle carrier. They constructed the outer layer out of cationicor positively chargedsegments of the polymers.
But not only did the particles stay in place, they were also able to bind with the polymeric matrix
and potentially lead to applications in fields like nanomanufacturing and catalysis. We understand how particles work in 3-D,
the particles will bounce off each other and make a nice suspension, meaning you can do work with them.
Even when particles are able to stay at the interface they tend to clump together and form a skin that cant be pulled back apart into its constituent particles.
The teams technique for surmounting this problem hinged on decorating their gold nanoparticles with surfactant, or soap-like, ligands.
and the way they are attached to the central particle allows them to contort themselves so both sides are happy
when the particle is at an interface. This arrangement produces a flying saucer shape, with the ligands stretching out more at the interface than above or below.
These ligand bumpers keep the particles from clumping together. To get a picture of how the particles packed in their 2-D layer
the researchers dripped a particle-containing an oil droplet out of a pipette into water.
Over time, particles attached to the oil-water interface, at which point the researchers could change their packing density by sucking some of the oil back into the pipette.
By measuring the optical properties of the particles when overcrowding pushed some out, they could work backwards to the number of particles on the interface.
From there, they could determine some universal rules that govern the physics of such systems. This is a very beautiful system,
Stebe says. The ability to tune their packing means that we can now take everything we know about the equilibrium thermodynamics in two dimensions
and start to pose questions about particle layers. Do these particles behave like we think they should?
How can we manipulate them in the future e
#PI's New Motion Simulator'Shaker'Hexapod Based on Fast Linear Motors (Nanowerk News) PI (Physik Instrumente) LP, a leading manufacturer of precision motion
As the focused electron beam passed through the object it excited the crescent energetically, causing it to emit photons, a process known as cathodoluminescence.
Both the intensity and the wavelength of the emitted photons depended on which part of the object the electron beam excited,
Atre said. For instance, the gold shell at the base of the object emitted photons of shorter wavelengths than
when the beam passed near the gap at the tips of the crescent. By scanning the beam back and forth over the object,
the engineers created a 2-D image of these optical properties. Each pixel in this image also contained information about the wavelength of emitted photons across visible and near-infrared wavelengths.
This 2-D cathodoluminescence spectral imaging technique pioneered by the AMOLF team, revealed the characteristic ways in
The technique can be used to probe many systems in which light is emitted upon electron excitation."
"This is an electron wave in a phosphorus atom, distorted by a local electric field. Unlike conventional computers that store data on transistors and hard drives, quantum computers encode data in the quantum states of microscopic objects called qubits.
Associate professor Morello said the method works by distorting the shape of the electron cloud attached to the atom,
which the electron responds.""Therefore, we can selectively choose which qubit to operate. It's a bit like selecting which radio station we tune to,
Attempts to use polymers with benzene-like delocalised electron bonding alleviated issues around the thermal durability to a certain extent.
They used a fused ring system of molecules with benzene-like delocalised electron bonding so that the material would readily crystallise.
This interaction leads to a rapid creation of an electron distribution with an elevated electron temperature.
and rapidly converted into electron heat. Next, the electron heat is converted into a voltage at the interface of two graphene regions with different doping.
This photo-thermoelectric effect turns out to occur almost instantaneously, thus enabling the ultrafast conversion of absorbed light into electrical signals.
Such particles could be used to detect oil underground or aid removal in the case of oil spills.
which rely on the drift and diffusion of electrons and their holes through semiconducting material, memristor operation is based on ionic movement,
The ionic memory mechanism brings several advantages over purely electron-based memories which makes it very attractive for artificial neural network implementation,
he said. ons are also much heavier than electrons and do not tunnel easily, which permits aggressive scaling of memristors without sacrificing analog properties.
#Researchers create first whispering gallery for graphene electrons (Nanowerk News) An international research group led by scientists at the U s. Commerce departments National Institute of Standards
and Technology (NIST) has developed a technique for creating nanoscale whispering galleries for electrons in graphene. The development opens the way to building devices that focus
and amplify electrons just as lenses focus light and resonators (like the body of a guitar) amplify sound.
issue of Science("Creating and probing electron whispering-gallery modes in graphene")."An international research group led by scientists at NIST has developed a technique for creating nanoscale whispering galleries for electrons in graphene.
The researchers used the voltage from a scanning tunneling microscope (right) to push graphene electrons out of a nanoscale area to create the whispering gallery (represented by the protuberances on the left),
which is like a circular wall of mirrors to the electron. Image: Jon Wyrick, CNST/NIST) In some structures,
such as the dome in St pauls Cathedral in London, a person standing near a curved wall can hear the faintest sound made along any other part of that wall.
These whispering galleries are unlike anything you see in any other electron based system, and thats really exciting.
However, early studies of the behavior of electrons in graphene were hampered by defects in the material.
When moving electrons encounter a potential barrier in conventional semiconductors it takes an increase in energy for the electron to continue flowing.
As a result, they are reflected often, just as one would expect from a ball-like particle.
However, because electrons can sometimes behave like a wave, there is a calculable chance that they will ignore the barrier altogether,
a phenomenon called tunneling. Due to the light-like properties of graphene electrons, they can pass through unimpededno matter how high the barrierif they hit the barrier head on.
This tendency to tunnel makes it hard to steer electrons in graphene. Enter the graphene electron whispering gallery.
To create a whispering gallery in graphene the team first enriched the graphene with electrons from a conductive plate mounted below it.
With the graphene now crackling with electrons, the research team used the voltage from a scanning tunneling microscope (STM) to push some of them out of a nanoscale-sized area.
This created the whispering gallery, which is like a circular wall of mirrors to the electron.
An electron that hits the step head-on can tunnel straight through it, said NIST researcher Nikolai Zhitenev.
But if electrons hit it at an angle, their waves can be reflected and travel along the sides of the curved walls of the barrier until they began to interfere with one another,
creating a nanoscale electronic whispering gallery mode. The team can control the size and strength, i e.,
, the leakiness, of the electronic whispering gallery by varying the STM tips voltage. The probe not only creates whispering gallery modes,
Working at the Center for Nanoscale Materials (CNM) and the Advanced Photon Source (APS), two DOE Office of Science User Facilities located at Argonne,
when hit with an electron beam. Equally importantly they have discovered how and why it happens.
When floated on water the particles form a sheet; when the water evaporates, it leaves the sheet suspended over a hole.
When the electron beam hits the molecules on the surface it causes them to form an additional bond with their neighbors,
Argonne researchers are able to fold gold nanoparticle membranes in a specific direction using an electron beam
They envision zapping only a small part of the structure with the electron beam, designing the stresses to achieve particular bending patterns.
As a conductor, graphene lets electrons zip too fasthere no controlling or stopping themhile boron nitride nanotubes are
so insulating that electrons are rebuffed like an overeager dog hitting the patio door. But together, these two materials make a workable digital switch
which is the basis for controlling electrons in computers, phones, medical equipment and other electronics. Yoke Khin Yap, a professor of physics at Michigan Technological University, has worked with a research team that created these digital switches by combining graphene and boron nitride nanotubes.
or differences in how much energy it takes to excite an electron in the material. hen we put them together,
you form a band gap mismatchhat creates a so-called otential barrierthat stops electrons. The band gap mismatch results from the materialsstructure:
caused by the difference in electron movement as currents move next to and past the hairlike boron nitride nanotubes.
These points of contact between the materialsalled heterojunctionsre what make the digital on/off switch possible. magine the electrons are like cars driving across a smooth track,
With their aligned atoms, the graphene-nanotube digital switches could avoid the issues of electron scattering. ou want to control the direction of the electrons,
slows down and redirects electrons. his is difficult in high speed environments, and the electron scattering reduces the number and speed of electrons.
Much like an arcade enthusiast, Yap says he and his team will continue trying to find ways to outsmart
or change the pinball setup of graphene to minimize electron scattering. And one day all their tweaks could make for faster computersnd digital pinball gamesor the rest of us t
and electrons in metal surfaces to develop novel components for optical data transmission between chips. The project is funded under the 7th Research Framework Programme of the European union
As recently published in AIP Applied Physics Letters("Patterned graphene ablation and two-photon functionalization by picosecond laser pulses in ambient conditions),
#Integration of quantum dots and photonic crystals produce brighter, more efficient light Recently, quantum dots (QDS) ano-sized semiconductor particles that produce bright, sharp,
"For this research, the team used the Center for Nanoscale Materials as well as beamline 12-ID-C of the Advanced Photon Source, both DOE Office of Science User Facilities.
Curtiss said the Advanced Photon Source allowed the scientists to observe ultralow loadings of their small clusters, down to a few nanograms,
In addition, as an actual needle application, we demonstrated fluorescenctce particle depth injection into the brain in vivo,
because they have the ability to capture individual photons of light. When fashioned into certain shapes, with specifically patterned surfaces,
they can channel photons along their surface, focusing their energy into a tight spot. When the material is a metal,
or the development of silicon computing chips that process data communicated by photons of light instead of electricity.
because they are relatively cheap and easy to fashion into the right shapes needed to channel photons the right way.
"The cloud of free-moving electrons around a metal that carries an electrical current can also absorb passing photons.
but their electrons absorb fewer passing photons.""While this extremely localised and directed heating effect has been put to some good uses like targeting cancerous cells to kill them,
First, the control voltage mediates how electrons pass through a boundary that can flip from an ohmic (current flows in both directions) to a Schottky (current flows one way) contact and back.
"We transferred electrons from the dopant-potassium-to the surface of the black phosphorus, which confined the electrons
and allowed us to manipulate this state. Potassium produces a strong electrical field which is required what we to tune the size of the band gap."
"This process of transferring electrons is known as doping and induced a giant Stark effect, which tuned the band gap allowing the valence
Now, researchers from the University of Bristol in the UK and Nippon Telegraph and Telephone (NTT) in Japan, have pulled off the same feat for light in the quantum world by developing an optical chip that can process photons in an infinite number
This result shows a step change for experiments with photons and what the future looks like for quantum technologies.
Now anybody can run their own experiments with photons, much like they operate any other piece of software on a computer.
The conjecture is that this arises from an avalanche of electrons from the top surface of the film to the bottom,
where the electrons are confined near the substrate. This shift of electric charge occurs as the manganese atomic layers form atomically charged capacitors leading to the build up of an electric field, known as polar catastrophe
Of particular importance are new materials that conduct electricity by using missing electrons, otherwise known as"holes."
Although electron conducting (n-type) TCOS are presently in use in many devices, their hole-conducting (p-type) counterparts have not been commercialized as candidate materials
and elsewhere using a technique called spin-polarized neutron reflectometry. They say the new finding could be used to probe a variety of exotic physical phenomena,
Possible applications of the new findings include the creation of spintronics, transistors based on the spin of particles rather than their charge.
particles predicted in 1937 but not yet observed, which, unlike all known subatomic particles, serve as their own antiparticles.
These theorized particles ave yet to be explored. It opens another avenue to explore these things
he says. he significance of this work is threefold, says Qi-Kun Xue, a professor of physics at Tsinghua University in China who was involved not in this work.
#Information storage and retrieval in a single levitating colloidal particle Thanks to this new technique developed by scientists at the University of Zurich,
'click on image to enlarge) Colloids are minute particles that are distributed finely throughout a liquid.
Suspensions of colloidal particles are most familiar to us as beverages, cosmetics and paints. At a diameter in the range of ten to one hundred nanometres, a single such particle is invisible to the naked eye.
These nanoparticles are constantly in motion due to the principle of Brownian motion. Since the particles are charged electrically,
they experience forces of attraction and repulsion that can be harnessed to control and manipulate their behavior.
They were able to organise the tiny particles into new structures with the utmost precision
and each individual particle can now be used to store and retrieve data, "explains Madhavi Krishnan.
#Electrons that stick together, superconduct together The discovery of a surprising feature of superconductivity in an unconventional superconductor by a RIKEN-led research team provides clues about the superconducting mechanism in this material
Superconductivity occurs as the result of pairs of electrons binding together in such a way that they act as a single quasiparticle.
the binding force is provided by vibrations in the atomic lattice through which the electrons travel.
or spin fluctuation of the electrons themselves, which binds electrons in pairs through the entanglement of electron spins.
However recent experiments have shown that this mechanism cannot explain the superconducting state in the quintessential unconventional superconductor Cecu2si2.
Inspired by this result, Michi-To Suzuki and Ryotaro Arita from the RIKEN Center for Emergent Matter Science, in collaboration with Hiroaki Ikeda from Ritsumeikan University in Japan, investigated the mechanism of electron pairing in 2si2
The electrons in Cecu2si2 can interact by entanglement of both spin and orbital states, resulting in multiple possible configurations or degrees of freedom.
but to their surprise, the researchers found that multipole fluctuations can also produce bound pairs of electrons,
This kind of electron binding may also be present in the recently discovered class of high-temperature iron-based superconductors. e found that the origin of the unconventional superconductivity in Cecu2si2 is an exotic multipole degree of freedom consisting of entangled spins
and have applications in superresolution microscopy, laser cutting, and particle acceleration.""You generally would need a large optical setup,
#Quantum dot solar cell exhibits 30-fold concentration We've achieved a luminescent concentration ratio greater than 30 with an optical efficiency of 82-percent for blue photons,
and photonic mirrors suffer far less parasitic loss of photons than LSCS using molecular dyes as lumophores.
and reabsorption and scattering of propagating photons. We replaced the molecular dyes in previous LSC systems with core/shell nanoparticles composed of cadmium selenide (Cdse) cores
while reducing photon re-absorption, says Bronstein. The Cdse/Cds nanoparticles enabled us to decouple absorption from emission energy and volume,
and excel at transmitting electrons and heat. But when the two are joined, the way the atoms are arranged can influence all those properties. ome labs are actively trying to make these materials or measure properties like the strength of single nanotubes and graphene sheets,
#Physicists discover spiral vortex patterns from electron waves In their new study("Electron Vortices in Photoionization by Circularly Polarized Attosecond Pulses),
when an electron is ejected, or ionized, from its orbit around a helium atom. Like all subatomic particles, electrons occupy a realm governed by quantum mechanics.
This means that their position, velocity and other properties are probabilistic, existing within a range of possible values.
Electrons can also exhibit the behavior of waves that, like ripples in a pond often gain or lose amplitude as they cross paths.
By firing two time-delayed, ultrashort laser pulses at a helium atom, the researchers found that the distribution of momentum values for these intersecting electron waves can take the form of a two-armed vortex that resembles a spiral galaxy.
the team study is the first to produce the pattern with electrons. In doing so, it also dramatically demonstrates the wavelike property of matter,
Starace called the pattern an xcellent diagnostic toolfor characterizing electron-manipulating laser pulses which occur on such fast time scales that physicists have sought multiple ways to measure their durations and intensities.
whereas the duration of the pulses corresponds to the width of the arms. f you use (longer) pulses to probe the electrons,
in materials revealed by electron tomography")."For more than 100 years, researchers have inferred how atoms are arranged in three-dimensional space using a technique called X-ray crystallography,
which a beam of electrons smaller than the size of a hydrogen atom is scanned over a sample
and measures how many electrons interact with the atoms at each scan position. The method reveals the atomic structure of materials
because different arrangements of atoms cause electrons to interact in different ways. However scanning transmission electron microscopes only produce two-dimensional images.
The downside of this technique is repeated that the electron beam radiation can progressively damage the sample.
thanks to the electron beam energy being kept below the radiation damage threshold of tungsten. Miao and his team showed that the atoms in the tip of the tungsten sample were arranged in nine layers, the sixth
and some of those photons interfere with one another and find their way onto a detector,
a computer then reconstructs the path those photons must have taken, which generates an image of the target material--all without the lens that's required in conventional microscopy."
The table-top machines are unable to produce as many photons as the big expensive ones
hardly any photons will bounce off the target at large enough angles to reach the detector.
Without enough photons, the image quality is reduced. Zürch and a team of researchers from Jena University used a special, custom-built ultrafast laser that fires extreme ultraviolet photons a hundred times faster than conventional table-top machines.
With more photons, at a wavelength of 33 nanometers, the researchers were able to make an image with a resolution of 26 nanometers--almost the theoretical limit."
"Nobody has achieved such a high resolution with respect to the wavelength in the extreme ultraviolet before, "Zürch said.
Overtext Web Module V3.0 Alpha
Copyright Semantic-Knowledge, 1994-2011