#Quantum computer technology now capable of holding data with 99 percent accuracy Perhaps the zaniest property of quantum mechanics is that of entanglement,
which is the weird instantaneous connection that exists between two entangled particles no matter their distance from one another.
First, the scientists refined a technique used to turn phosphorous atoms into qubits, the units of measurement for quantum information.
Second, they manufactured an"artificial atom"using a silicon resistor. Taken together, the two methods improved the reliability of data retention from just 50 percent to over 99 percent
The trick to improving the accuracy of the technology was to select for specific silicon isotopes that have no magnetic spin,
because magnetic spin can mess with the phosphorous atoms that the qubits are made of.""In natural silicon each atom also has its own spin
which affects the phosphorous atom, which is why the accuracy was only 50 per cent,
"said Dzurak.""We solved the problem by removing all the silicon 29 isotopes that have magnetic spin leaving only silicon 28,
which has no magnetic spin to influence the phosphorous, giving us an accuracy of 99.99 per cent."
"Scientists also said they were able to increase the length of time with which information was retained in their silicon qubits, a function known as"coherence time."
reports Princeton News. The minuscule device is powered by individual electrons that tunnel through artificial atoms known as"quantum dots,
"It is basically as small as you can go with these single-electron devices, "said Jason Petta,
When turned on, electrons flow single-file through each double quantum dot which causes them to emit photons in the microwave region of the spectrum.
The photons can then be channeled into a coherent beam of light using mirrors. Aside from its importance in the development of quantum computers, the maser could also lead to advancements in a variety of fields such as communications, sensing and medicine,
or any other discipline that utilizes technology which relies on coherent light sources.""In this paper the researchers dig down deep into the fundamental interaction between light
and the moving electron,"said Claire Gmachl, professor of electrical engineering at Princeton.""The double quantum dot allows them full control over the motion of even a single electron,
and in return they show how the coherent microwave field is created and amplified. Learning to control these fundamental light-matter interaction processes will help in the future development of light sources
It not exactly a gamer rig, with an Atom processor and 2gb of ram and a 32 GB solid state drive,
Nature News The ones and zeroes that propel the digital world the fording of electrons across a transistor,
or hard drives reliant on electrons'intrinsic spin are getting packed into smaller and smaller spaces. The limit was thought to be set:
no more than one bit of information could be encoded on an atom or electron. But now, researchers at Stanford university in Palo alto, California, have used another feature of the electron its tendency to bounce probabilistically between different quantum states to create holograms that pack information into subatomic spaces.
By encoding information into the electron's quantum shape, or wave function, the researchers were able to create a holographic drawing that contained 35 bits per electron."
"Our results will challenge some fundamental assumptions people had about the ultimate limits of information storage,
"says graduate student Chris Moon, one of the authors of the work published in Nature Nanotechnology1.
when researchers at IBM manipulated individual xenon atoms on a nickel plate to spell out the letters'IBM'across a space just a dozen nanometres wide2.
They would use the quantum properties of electrons, rather than photons, as their source of'illumination'.'Using a scanning tunnelling microscope, they stuck carbon monoxide molecules onto a layer of copper their holographic plate.
The molecules were positioned to create speckled patterns that would result in a holographic'S'.The sea of electrons that exists naturally at the surface of the copper layer served as their illumination.
Just as water bouncing off stones in a show pond create a rippling wave patterns, these electrons interfere with the carbon monoxide molecules to create a quantum hologram.
The researchers read the hologram using the microscope to measure the energy state of a single electron wave function.
They showed they could read out an'S'for Stanford with features as small as 0. 3 nanometres.
They teased out the individual pages by scanning the hologram for electrons at different energy levels.
In encoding the'S',the researchers were concentrating the electron density at certain points and energy levels.
And a concentration of electrons in space is, in essence, a wire. That led study co-author Hari Manoharan to think about using the holograms as stackable quantum circuits
The quantum electron holography, for now, requires the tunnelling microscope, which traverses the hologram more slowly."
Fish make calcium carbonate by combining calcium from seawater with carbonate ions generated from CO2 in their bodies.
If the amount of atmospheric CO2 goes up as expected leading to a CO2 increase in the oceans the fish may produce more carbonate ions and thus more calcium carbonate.
Nature News A transparent, flexible electrode made from graphene could see a one-atom thick honeycomb of carbon first made just five years ago replace other high-tech materials used in displays.
The results in Hong's case were relatively large, high-quality films of graphene just a few atoms thick and several centimetres wide.
and by cooling the sample quickly after the reaction the researchers could produce up to ten single-atom layers of carbon in graphene's signature honeycomb pattern.
And in September, France signed an agreement similar to the US one to share nuclear technology and know-how with India.
and Padmanabha Krishnagopala Iyengar, former DAE secretary, claim that Indian nuclear scientists are giving up prematurely on their thorium research programme in exchange for a few uranium reactors from abroad.
India has very little domestic uranium but one-quarter of the world's thorium reserves;
its thorium research programme focuses on turning the material into fissile uranium-233 for use as reactor fuel.
Fast breeder reactors, of the type under construction in Kalpakkam, would breed uranium-233 in thorium blankets surrounding a plutonium core.
Recovering plutonium and uranium-233 from spent fuel is key to India's thorium programme,
Still, at least one overseas company is betting on thorium. Last month, Thorium power in Mclean, Virginia, with a market capitalization of about $40 million
laboratory chemicals or low energy light bulbs that contain mercury.""I don't think these areas where mercury still has important uses will be the first to go,
and radiation to destroy their own blood-producing stem cells. The procedure leaves them vulnerable to infection,
but sulphate and soot particles from fossil fuel burning are the main culprits, the team found."
aerosol particles can act as seeds for clouds, which help to reflect the Sun's rays back into space
Work by two independent groups will make it easier to find out the structure of single biological molecules such as proteins without destroying
They work by detecting how molecules collectively resonate#like guitar strings that vibrate together#with electromagnetic waves of specific wavelengths.
But to some researchers, whole bodies are less interesting than the molecules that they are made up of."
Probing single molecules a few nanometres wide has been a major frustration in NMR. The detectors need to be a similar size to the sample
Both teams made diamonds with defects in their crystal structure#a single nitrogen atom next to a missing carbon atom, a few nanometres below the surface.
which way the nitrogen s electrons are spinning. Reinhard s team placed different kinds of samples onto their diamond
and watched how the nuclear resonance in them influenced the spinning electrons in the nitrogen. The researchers worked out that most of the signal came from a volume just 5 nanometres across inside the sample.
which allowed them to manipulate the electrons of hydrogen atoms inside it. That was much more like a conventional NMR experiment,
and provided more detail about the kind of molecule being probed.""Our technique is purely passive, says Reinhard,
imaging single molecules inside living cells. Diamond nanocrystals immersed in a cell's cytoplasm could essentially produce real-time films of the activity of single molecules,
such as a protein folding, writes Philip Hemmer, a solid-state physicist at Texas A&m University in College Station."
when the fusion of different cultures#Western and Eastern#and the exchange of ideas gave rise to enormous prosperity and self-confidence,
bacteria accounted for around 20%of all particles#biological and non-biological#a higher proportion than in the near-Earth atmosphere."
when water molecules in the air coalesce around a seed particle, often dust or soot. Depending on temperature, these complexes can grow into large water droplets or frozen balls of ice,
For example, CERN, the European particle-physics lab near Geneva, currently stores around 90 petabytes of data on some 100 tape drives.
but that will rarely be accessed, such as CERN s data. If costs fall by 100-fold in ten years,
which will get#2. 9 billion to spruce up its ageing beamlines, used for structural studies of materials and proteins.
and its goal is to develop the design for a facility that could be completed in the 2030s in Daejeon, under the leadership of the country s National Fusion Research Institute (NFRI).
but the government and fusion scientists were steady and serious about getting the job done,
a research fellow at NFRI and a former chairman of the ITER Management Advisory Committee, says that Korea is need desperately in of the energy that fusion could provide."
the water s oxygen atoms share some of their electrons with vacant electron orbitals on the aluminium atoms,
and the oxygens in the ceramic share their electrons with hydrogen in the water. This binds the two together.
But what if a ceramic failed to accept electrons from water? Then the ceramic might actually be reasoned hydrophobic
The lanthanides'empty orbitals are buried beneath shells of other electrons, which should make them much less attractive to water s oxygen,
missing oxygen atoms#that allowed water to latch on. Cheung suggests that Varanasi's ceramics were particularly hydrophobic
it is based not on carbon but on a latticework of boron and nitrogen atoms. Computer simulations have indicated that a rare crystalline form of boron nitride would resist indentation even better than diamond
A nanotwin is a crystalline segment that mirrors the orientation of atoms on the other side of an interface (a so-called twin boundary) within a material.
which the atoms of nitrogen and boron form an onionlike structure of nested layers. Pressed into macroscopic pellets
Researchers working with nanoscale fluorescent particles called quantum dots have predicted long groundbreaking achievements, such as ultra-efficient light-emitting diodes (LEDS) and solar cells,
and size affect the quantum properties of their electrons, in particular their energy gap#the energy needed to kick electrons into a higher energy band#which determines the colour of light that the mater#ial can emit.
Whereas a bulk semiconductor is limited to emitting a single colour of light researchers can tune the precise colour a quantum dot will absorb
who prize them as fluorescent imaging labels for proteins and other biological molecules. As recently as 2010, the biomedical sector was responsible for US$48#million of $67#million in total quantum dot revenues, according to BCC Research of Wellesley, Massachusetts.
to make them more appealing as long-life, low energy light bulbs. But Bawendi says that LED designs
About a quarter past a kilogram Physicists have created an atomic clock that relies on a fundamental link between time and mass.
The researchers, at the University of California, Berkeley, say that the pulse of the clock is determined solely by the mass of its beating heart, a caesium atom.
Current atomic clocks are based on the microwave signals emitted by electrons inside an atom as they move from one energy level to another.
But those internal atomic oscillations are determined by the interactions between the atom s electrons and its nucleus
not to mention other quantum effects, such as spin, the quantum analogue of magnetic moment. The oscillations are defined well,
M#ller and his colleagues say that their work goes back to the basics of quantum mechanics#to Arthur Compton's demonstration in 1923 that X-ray photons can deliver a detectable momentum impulse to an electron,
and to Louis de Broglie's subsequent insight that moving electrons (and atoms) behave like waves.
The characteristic Compton frequency used to describe these matter waves is around 1020 Hz for an electron,
and 3#1025 Hz for a caesium atom.##Nevertheless, using a combination of atom interferometry and ultra-precision laser techniques,
M#ller and his team have, in essence, found a way to count those Compton cycles.
#which is where atom interferometry comes in. The researchers used a cloud of around 1 million caesium atoms divided in two.
One half was given a series of 10 kicks, or tiny laser-photon impacts, which slow the Compton cycles by a precisely known amount.
The quantum interference occurs when the manipulated half of the cloud of atoms is reunited with the unaltered half:
the output signal of the interferometer is at a maximum when the two populations differ by an integral number of cycles.
the locked frequency is then the pulse of the new atomic clock. M#ller makes no great claims for the precision of the clock.
With an accuracy of 4 parts per billion,"it s no better than the original atomic clocks 50 years ago, he says.
But what is more important, M#ller says is that the only physical parameter that appears in the expression for the clock frequency is the mass of the caesium atoms."
"involves a reference using at least two particles that interact. This Compton clock is the first to be based entirely on a single particle s mass.
That means that the device, which in principle can be built with a single atom, M#ller says,
could serve as the foundation for a new definition of the kilogram tied to a precise laser frequency.
adding, Any atomic clock involves masses. But nowhere in their experiment, does a real Compton oscillator at 1025 Hz appear!
"His experiments have forced a lot of people to think very clearly about profound aspects in this arena of atomic physics and relativity i
Miriam Wilsonwith molecules for moving parts, this nanorobot links together amino acids (colored balls) by attaching them to a moving ring (blue.
Leigh s system relies on a rotaxane#a large molecular ring threaded onto another molecule that acts as an axle.
But he hopes that it could help to move chemistry beyond its two-centuries-old habit of making molecules using stepwise processes#adding a chemical group
Molecular machines inspired by biology could eventually enable chemists to build materials with a specific sequence of molecules#a strand of polystyrene in which each component bears one of a range of extra chemical groups, for example.
and helium#a hallmark of having formed early in the history of the Universe, before successive generations of stars had a chance to forge heavier elements.
which did not contain appreciable amounts of elements heavier than helium, he notes. That means that as old as HD 140283 is, its chemical composition
#Electron beams set nanostructures aglow Put a piece of quartz under an electron microscope and it will shine an icy blue.
But the light#emitted after a beam of electrons kicks a material s own electrons into a higher energy state#is faint and diffuse,
The technique combines the advantages of optical and electron-based imaging. An electron beam can in principle achieve a resolution of less than one nanometre,
compared with hundreds of nanometres for a beam of light. But maps made by scattered or reflected electrons are not typically sensitive to the way light behaves in the sample.
Cathodoluminescence, by contrast, can map the interaction of light and matter#but, because it is triggered by a narrow beam of electrons,
it promises the same nanometre scale resolution that those systems can achieve.""This has opened the door to understanding how light couples to matter in a more fundamental way,
The device includes a carefully shaped parabolic mirror that collects photons as they emerge from a sample bombarded with electrons.
and a spectrometer to resolve the origin and energy of the light (see Metamaterial TV).
Just as in an old-fashioned cathode ray tube-tube colour television, the electron beam scans the sample to build up an image line by line.
Physicists later realized that the absolute temperature of a gas is related to the average energy of its particles.
which particles have no energy at all, and higher temperatures correspond to higher average energies. However, by the 1950s, physicists working with more exotic systems began to realise that this isn't always true:
Technically, you read off the temperature of a system from a graph that plots the probabilities of its particles being found with certain energies.
Normally, most particles have average or near-average energies, with only a few particles zipping around at higher energies.
In theory, if the situation is reversed, with more particles having higher, rather than lower energies, the plot would flip over
and the sign of the temperature would change from a positive to a negative absolute temperature,
Schneider and his colleagues reached such sub-absolute-zero temperatures with an ultracold quantum gas made up of potassium atoms.
they kept the individual atoms in a lattice arrangement. At positive temperatures, the atoms repel,
making the configuration stable. The team then quickly adjusted the magnetic fields, causing the atoms to attract rather than repel each other."
"This suddenly shifts the atoms from their most stable, lowest-energy state to the highest possible energy state,
before they can react, says Schneider.""It s like walking through a valley, then instantly finding yourself on the mountain peak.
and the atoms would collapse inwards. But the team also adjusted the trapping laser field to make it more energetically favourable for the atoms to stick in their positions.
This result, described today in Science1, marks the gas s transition from just above absolute zero to a few billionths of a Kelvin below absolute zero.
says Achim Rosch, a theoretical physicist at the University of Cologne in Germany, who proposed the technique used by Schneider and his team3.
whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature,
some atoms will move upwards, apparently defying gravity4. Another peculiarity of the sub-absolute-zero gas is that it mimics'dark energy'
Schneider notes that the attractive atoms in the gas produced by the team also want to collapse inwards,
#Memory molecule dethroned For years, a particular protein has been cast as a lynchpin of long-term memory.
But two independent groups of US scientists have challenged now seriously the role of this'memory molecule'by developing mice that completely lack it
#Ephemeral third ring of radiation makes appearance around Earth First discovered in 1958, the Van allen belts have been thought to comprise two reservoirs of high-speed,
electrically charged particles, corralled into separate doughnut-shaped rings by Earth s magnetic field. The outer ring orbits at a distance of some 10,000-60,000 kilometres above Earth,
and encircles an inner band of even more energetic particles, roughly 100-10,000 kilometres above Earth.
narrow belt of charged particles sandwiched between the inner ring and a now highly eroded outer ring."
however, and Baker and his team now attributes its creation to an interplanetary shock wave#a travelling outburst of solar-wind particles from the Sun#that has been detected by other craft.
NASATHE two Van allen Probes orbit through the radiation belts that surround Earth, shown in cross section in this artist's impression.
naturally occurring circular RNA molecules that influence gene expression. At least some of the loops, described in two papers published this week by Nature1,
The molecules comprise"a hidden, parallel universe of unexplored RNAS, says Nikolaus Rajewsky, the lead author of one of the studies and a systems biologist at the Max Delbr#ck Center for Molecular Medicine in Berlin.
while searching for RNA molecules that conventional methods might have missed3. And when Rajewsky and his colleagues mined databases for circular RNA molecules, they found thousands in nematode worms, mice and humans."
"It s yet another terrific example of an important RNA that has flown under the radar,
all therapeutic molecules face a deadly foe#the immune system. Its macrophages are designed to spot any intruding molecules in the blood
and destroy them in a process called phagocytosis. Researchers at the University of Pennsylvania in Philadelphia have now found a way to stop macrophages from destroying drug-bearing nanoparticles.
This means that molecules that contain CD47 can get past macrophages and into blood cells. Biophysicist Dennis Discher, who led the work,
"It s a new way of trying to get the immune system to prevent phagocytosis of drugs or particles.
#Small-molecule drug drives cancer cells to suicide Cancer researchers have pinned down a molecule that can kick-start the body s own tumour-destroying systems,
The molecule, TIC10, activates the gene for a protein called TRAIL (tumour-necrosis-factor-related apoptosis-inducing ligand),
all of us with functional immune systems use this molecule to keep tumours from forming or spreading,
The molecule is so compact that it can cross the blood-brain barrier, which separates the main circulatory system from the brain.
"We didn t actually anticipate that this molecule would be able to treat brain tumours#that was a pleasant surprise,
the initiative will build and curate a collection of 500,000#molecules for screening, 300,000 of which will come from the seven large pharmaceutical partners.
The rest#intended to cover classes of biologically active molecule that are represented poorly in current libraries#will be formulated
the pharmaceutical partners will be able to use the library#including molecules from their competitors#in their own drug screens.
Any academic group or company can also propose assays to test molecules in the library for biological activity.
The hope is that members will build on the results to improve the molecules biological properties
These molecules can then be licensed back to companies for further development. The scheme hopes to become self-sustaining by requiring milestone payments as drugs move from laboratory to clinic and from additional partnerships and screening services."
An effort launched by the US National institutes of health in 2004 called the Molecular Libraries Program (MLP) built a 400,000-compound library of commercially available molecules,
and the shapes of thousands of other molecules is getting an upgrade. A method described in Nature this week1 makes X-ray crystallography of small molecules simpler, faster and more sensitive,
largely doing away with the laborious task of coaxing molecules to form crystals. Instead, porous scaffolding holds molecules in the orderly arrangement needed to discern their structure with X-rays.
You could call it crystal-free crystallography, says Jon Clardy, a biological chemist at Harvard Medical school in Boston,
Massachusetts, who was involved not in the work but wrote a commentary accompanying the paper2. X-ray crystallography is one of the most important techniques in science,
because it is one of only a few ways to directly determine the shape of large molecules.
It does this by blasting molecules with X-rays and measuring how their rays are diffracted. Transforming these reflections into molecular models isn t simple.
But cajoling many molecules to crystallize is tedious and time-consuming#like getting a puppy to sit still for a photograph#and,
These materials acted as'crystalline sponges',mopping up tiny quantities of small molecules after a short incubation period and holding them in an ordered arrangement within a cage-like scaffold.
the researchers used their technique to correctly determine the shape of several small molecules, the structures of which were known already.
The molecule has evaded crystallization because its sinewy shape causes it to flop around.""It s a remarkable achievement, says Clardy.
because it is often difficult to determine the shape of these molecules from the small quantities found in nature."
The scientists have identified also a molecule that can thwart the activity of the protein, one of a class known as multidrug and toxic compound extrusion transporters (MATES) that are found in cell membranes.
when a proton binds to the MATE protein at a spot on its extracellular side, one of the protein's segments switches from a straight to a bent shape to push any nearby foreign molecule out of the cell1."
"I think this is a major step forward, says Hendrik Van veen, a pharmacologist at the University of Cambridge, UK."
"They have a direct mechanism of how the protons change the shape of the cavity.
The map even shows that the number of neutrino flavours permeating the cosmos will probably remain at three#had there been a fourth,
particles such as protons and electrons formed from the cauldron of proto-matter, and photons began to bounce around like pinballs.
It was only 380,000#years later, when the charged plasma cooled into neutral atoms, that those photons could fly freely.
Today they make up the CMB, and carry with them an imprint of the quantum fluctuations that roiled the inflationary Universe.
Seen in the map as tiny variations around an average temperature of 2. 7 kelvins
the fluctuations caused alterations in the density of matter, which ultimately snowballed into the galaxies seen today."
Their giant but crude microwave receiver saw the radiation as being the same in all directions,
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