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Curator: Dr. Aviva Lev-Ari
One decade following the completion of the Sequencing of the Human Genome – the field of Genomics, the discipline that has emerged as a result of project completion has FOUR sections: Comparative Genomics, Genome Sequencing and Annotation, Functional Genomics, and Translational Genomics.
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The Einstein of popular thought is the young Einstein. This is the intellectual rebel of 1905 who, in one year, laid out the special theory of relativity and E=mc2, postulated the light quantum and used Brownian motion to make the case for the reality of atoms. These achievements were made prior to Einstein holding an academic position. He was then still a patent examiner in the Bern patent office. The years that followed brought Einstein a succession of ever more prestigious academic appointments; and, in the mid 1910s, he delivered his masterpiece, the general theory of relativity.
In all this, there was a real sense that Einstein was ahead of his peers, leading the way. The special theory of relativity was absorbed into the mainstream of physics fairly quickly. The general theory of relativity was not quite so readily accommodated. This was in part due to its burdensome mathematical demands of the theory, at least relative to the standards of mathematical expertise then found among physicists. But the tide was flowing with Einstein. When the eclipse expeditions of 1919 vindicated Einstein's theory and he became a popular hero, critics risked being seen as unimaginative reactionaries.
Einstein's work on the light quantum did not fare so well. It was regarded by many as an odd aberration from an otherwise brilliant mind. Even in the early 1920s, it was doubted by Niels Bohr, who had a decade before developed the first quantum model of the atom.
By the end of the 1920s, however, another Einstein began to emerge. As the quantum theory enjoyed success after success, Einstein found himself unconvinced. He took on the role of critic, complaining that the new quantum theory, for all its virtues, could not be the final theory. This was Einstein's new place in the physics community for his final quarter century, ending with his death in 1955. He remained a revered figure. But he became increasingly isolated and marginalized, as he labored on his alternative theories with the help of a few assistants. In the years after his death, it became clear that Einstein's objection to quantum theory failed, but not, for the reasons articulated by his arch antagonist Niels Bohr.
The old Einstein is a recalcitrant Einstein, unwilling to swim with the new quantum tide that flooded over physics. We should not judge that harshly. No thinker can ever think purely new thoughts. We all sit at the junction of the old and the new. Einstein was one of the first of new physicists of the twentieth century. His discoveries and methods exercised a profound, defining influence on the development of twentieth century physics. However, there is also a strong sense in which he was one of the last of the nineteenth century physicists. Perhaps he was the greatest of them. Delete the scoop?
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Within a nanometer-scale device, visible light travels infinitely fast—by one measure—a team of physicists and engineers reports. The gizmo won't lead to instantaneous communication—the famous speed limit of Albert Einstein's theory of relativity remains in force—but it could have a variety of uses, including serving as an element in a type of optical circuitry.
"The demonstration of such a thing is definitely very interesting and possibly useful," says Wenshan Cai, an electrical engineer at the Georgia Institute of Technology in Atlanta, who was not involved in the work.
In empty space, light always travels at 300,000,000 meters per second. In a material such as glass, it travels slower. The ratio of light's speed in the vacuum to its speed in a material defines the material's "index of refraction," which is typically greater than one. However, scientists have begun to manipulate the interactions of light and matter to tune the index of refraction in weird ways, such as making it negative, which leads to an unusual bending of light.
Now, Albert Polman, a physicist at the FOM Institute for Atomic and Molecular Physics in Amsterdam; Nader Engheta, an electrical engineer at the University of Pennsylvania; and colleagues have pulled off a particularly odd feat. They've developed a tiny device in which the index of refraction for visible light is zero—so that light waves of a particular wavelength move infinitely fast.
The device consists of a rectangular bar of insulating silicon dioxide 85 nanometers thick and 2000 nanometers long surrounded by conducing silver, which light generally doesn't penetrate. The result is a light-conveying chamber called a waveguide. Researchers fashioned different devices in which the width of the silicon dioxide ranged from 120 to 400 nanometers.
Light behaves differently in such a waveguide, because the electromagnetic fields must obey certain "boundary conditions" on the sides of the device. Short-wavelength light bounces back and forth between the ends of the guide, and the peaks and troughs of the counter-propagating light waves overlap to create a pattern of bright and dark bands much like the pressure patterns with a ringing organ pipe. Above a "cutoff" wavelength, light doesn't flow at all.
Right at the cutoff wavelength, things get interesting. Instead of producing a banded pattern, the whole waveguide lights up. That means that instead of acting as waves with equally spaced peaks, or "phase fronts," the wave behaves as if its peaks are moving infinitely fast and are everywhere at once. So the light oscillates in synchrony along the length of the waveguide. Engheta and company had previously created an index of refraction of zero for longer-wavelength radiation called microwaves. Repeating the feat for visible light was harder, as the new widget is too small to contain a light source. Instead, the researchers shot in a beam of electrons to generate light of all wavelengths within the waveguide and measured the light leaking out of it. The amount of light shining out at a particular wavelength depends on whether the electron beam enters at a point where there should be a dark or a bright spot for that wavelength. So by scanning the beam along the waveguide and monitoring the output, researchers traced the light pattern at each wavelength. "It is nanofabrication and characterization at its best," says Che Ting Chan, a physicist at the Hong Kong University of Science and Technology.
So how does an everywhere-at-once light wave not violate relativity? Light has two speeds, Engheta explains. The "phase velocity" describes how fast waves of a given wavelength move, and the "group velocity" describes how fast the light conveys energy or information. Only the group velocity must stay below the speed of light in a vacuum, Engheta says, and inside the waveguide, it does. The device could hav e various uses, Engheta says. Because the light leaking out of the waveguide is all in synch, the waveguide might be bent to form an antenna that emits light wave with sculpted phase fronts, he says. It might also make a conduit for a hoped-for type of nanoscale optical circuitry, he says.
An array of such waveguides might even make a bulk material with zero index of refraction. But fabricating that array would be very challenging, Cai says: "In theory it's easy; experimentally it's very hard." 
Josh C.'s curator insight,
March 13, 9:33 AM
I keep myslef hopeful of the future of this world. This is one of the ways that I can keep track of that. The new things we can do are amazing compared to just one decade ago! Delete the scoop?
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In the strange world of quantum mechanics, the vacuum state (sometimes referred to as the quantum vacuum, simply as the vacuum) is a quantum system's lowest possible energy state. While not containing physical particles, neither is it an empty void: Rather, the quantum vacuum contains fluctuating electromagnetic waves and so-called virtual particles, the latter being known to transition into and out of existence. In addition, the vacuum state has zero-point energy – the lowest quantized energy level of a quantum mechanical system – that manifests itself as the static Casimir effect, an attractive interaction between the opposite walls of an electromagnetic cavity. Recently, scientists at Aalto University in Finland and VTT Technical Research Centre of Finland demonstrated the dynamical Casimir effect using a Josephson metamaterial embedded in a microwave cavity. They showed that under certain conditions, real photons are generated in pairs, and concluded that their creation was consistent with quantum field theory predictions.
Modulating the effective length of the cavity by flux-biasing the SQUID (superconducting quantum interference device) metamaterial had its challenges as well. "The pump signal needs to be rather strong, yet at the same time one wants to be sure that no excess noise enters the system through the pump line, Lähteenmäki notes, "and good filtering means high attenuation, which is a requirement contradictory to a strong signal. Also," Lähteenmäki continues, "at 10.8 GHz the pump frequency is rather high – and at that frequency range both the sample and the setup is rather prone to electrical resonances which can limit the usable frequencies." In short, the flux profile needs to be such that the pumping doesn't counteract itself. In addition, trapping flux in SQUID loops can also become a problem, limiting the range of optimal operating points and causing excess loss.
The researchers also showed that photons at frequencies symmetric with respect to half the modulation frequency of the cavity are generated in pairs. "In general, with frequency locked signal analyzers today the extraction of this correlation is not particularly problematic – especially since the low noise amplifier noise is not correlated at different frequencies," Lähteenmäki explains. That said, issues related to data collection and averaging include amplifier gain drift and phase randomization of the pump signal (relative to the detection phase) if the state of the generator is changed. "The noise temperature of the low noise amplifier sets some limits to the amount of data that needs to be collected, especially in the case where one is operating in the regime of low parametric gain." Delete the scoop?
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A team of Chinese physicists have clocked the speed of spooky action at a distance — the seemingly instantaneous interaction between entangled quantum particles — at more than four orders of magnitude faster than light.
Their equipment and methodology doesn’t allow for an exact speed, but four orders of magnitude puts the figure at around 3 trillion meters per second. Spooky action at a distance was a term coined by Einstein to describe how entangled quantum particles seem to interact with each other instantaneously, over any distance, breaking the speed of light and thus relativity. As of our current understanding of quantum mechanics, though, it is impossible to send data using quantum entanglement, preserving the theory of relativity. A lot of work is being done in this area, though, and some physicists believe that faster-than-light communication might be possible with some clever manipulation of entangled particles.
Now, thanks to these Chinese physicists — the same ones who broke the quantum teleportation distance record last year — we know that spooky action at a distance has a lower bound of four orders of magnitude faster than light, or around 3 trillion meters per second. We say “at least,” because the physicists do not rule out that spooky action is actually instantaneous — but their testing equipment and methodology simply doesn’t allow them to get any more accurate.
To get this figure, the physicists entangled pairs of photons at a base station, and then transmitted half of each pair to two receiving sites. The receiving sites were 15.3 kilometers (9.5mi) apart, and aligned east-west so as to minimize the interference from the Earth’s rotation (which is significant, when measuring speed on this scale). One half of the pair was then observed, and the time for the other half to assume the same state is measured. This process was repeated continuously for 12 hours to generate enough data to accurately divine the speed of spooky action.
According to the physicists, other research groups have tried to measure the speed of spooky action before, but they’ve all had locality loopholes — flaws in the methodology that undermine the quantum nonlocality that the experiment requires. This time, the physicists claim, all the loopholes have been closed, and that their measurement of at least 3 trillion meters per second is accurate. 
Miro Svetlik's curator insight,
March 8, 8:14 AM
I've always knew that Light-speed spaceships are just too slow to really travel the universe :). What we really need is a proper implementation of quantum transportation. So smart guys get goin... Delete the scoop?
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Researchers at the University of Rochester and the University of Ottawa have applied a recently developed technique to directly measure for the first time the polarization states of light. Their work both overcomes some important challenges of Heisenberg's famous Uncertainty Principle and also is applicable to qubits, the building blocks of quantum information theory. The direct measurement technique was first developed in 2011 by scientists at the National Research Council, Canada, to measure the wavefunction -- a way of determining the state of a quantum system. Such direct measurements of the wavefunction had long seemed impossible because of a key tenet of the uncertainty principle -- the idea that certain properties of a quantum system could be known only poorly if certain other related properties were known with precision. The ability to make these measurements directly challenges the idea that full understanding of a quantum system could never come from direct observation.
The Rochester/Ottawa researchers, led by Robert Boyd, who has appointments at both universities, measured the polarization states of light -- the directions in which the electric and magnetic fields of the light oscillate. Their key result, like that of the team that pioneered direct measurement, is that it is possible to measure key related variables, known as "conjugate" variables, of a quantum particle or state directly. The polarization states of light can be used to encode information, which is why they can be the basis of qubits in quantum information applications.
"The ability to perform direct measurement of the quantum wavefunction has important future implications for quantum information science," explained Boyd, Canada Excellence Research Chair in Quantum Nonlinear Optics at the University of Ottawa and Professor of Optics and Physics at the University of Rochester. "Ongoing work in our group involves applying this technique to other systems, for example, measuring the form of a "mixed" (as opposed to a pure) quantum state." Delete the scoop?
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A quantum computer doesn't need to be a single large device but could be built from a network of small parts, new research from the University of Bristol has demonstrated. As a result, building such a computer would be easier to achieve. 
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February 26, 10:10 AM
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The researches of the Aalto University and the University of Oulu have succeeded to simulate a phenomenon called motional averaging, which demonstrates that in certain conditions externally-induced fast fluctuations in energy can help stabilize the state of the system. The study shows that noise is not necessarily detrimental to the functioning of quantum devices such as superconducting quantum bits, but under certain circumstances noise can even improve their characteristics. The measurements were conducted by applying a combination of microwave electronics and cryogenic techniques to a superconducting quantum circuit, where the energy fluctuations of the artificial atom were induced and controlled externally by a random signal generator. The research is a first step in the direction of emergent quantum technologies, based on the principles of quantum mechanics. Circuits such as those studied by the team are expected to perform simulations of quantum many-body phenomena enabling, for example, predictions of the properties of materials to an accuracy which is currently not available. Delete the scoop?
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Scientists are still sorting out the details of last year's discovery of the Higgs boson particle, but add up the numbers and it's not looking good for the future of the universe, scientists said.
"If you use all the physics that we know now and you do what you think is a straightforward calculation, it's bad news," Joseph Lykken, a theoretical physicist with the Fermi National Accelerator Laboratory in Batavia, Illinois. Lykeen spoke before presenting his research at the American Association for the Advancement of Science meeting in Boston.
"It may be that the universe we live in is inherently unstable and at some point billions of years from now it's all going to get wiped out," said Lykken, who is also on the science team at Europe's Large Hadron Collider, or LHC, the world's largest and highest-energy particle accelerator.
Physicists last year announced they had discovered what appears to be a long-sought subatomic particle called the Higgs boson, which is believed to give matter its mass.
Work to study the Higgs' related particles, necessary for confirmation, is ongoing. If confirmed, the discovery would help resolve a key puzzle about how the universe came into existence some 13.7 billion years ago - and perhaps how it will end.
"This calculation tells you that many tens of billions of years from now, there'll be a catastrophe," Lykken said. "A little bubble of what you might think of as an ‘alternative' universe will appear somewhere and then it will expand out and destroy us," Lykken said, adding that the event will unfold at the speed of light.
Scientists had grappled with the idea of the universe's long-term stability before the Higgs discovery, but stepped up calculations once its mass began settling in at around 126 billion electron volts - a critical number it turns out for figuring out the fate of the universe.
The calculation requires knowing the mass of the Higgs to within one percent, as well as the precise mass of other related subatomic particles. "You change any of these parameters to the Standard Model (of particle physics) by a tiny bit and you get a different end of the universe," Lyyken said.
Earth will likely be long gone before any Higgs boson particles set off an apocalyptic assault on the universe. Physicists expect the sun to burn out in 4.5 billion years or so, and expand, likely engulfing Earth in the process. Delete the scoop?
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A vacuum might seem like empty space, but scientists have discovered a new way to seemingly get something from that nothingness, such as light. And the finding could ultimately help scientists build incredibly powerful quantum computers or shed light on the earliest moments in the universe's history.
Quantum physics explains that there are limits to how precisely one can know the properties of the most basic units of matter—for instance, one can never absolutely know a particle's position and momentum at the same time. One bizarre consequence of this uncertainty is that a vacuum is never completely empty, but instead buzzes with so-called “virtual particles” that constantly wink into and out of existence.
These virtual particles often appear in pairs that near-instantaneously cancel themselves out. Still, before they vanish, they can have very real effects on their surroundings. For instance, photons—packets of light—can pop in and out of a vacuum. When two mirrors are placed facing each other in a vacuum, more virtual photons can exist around the outside of the mirrors than between them, generating a seemingly mysterious force that pushes the mirrors together.
This phenomenon, predicted in 1948 by the Dutch physicist Hendrick Casimir and known as the Casimir effect, was first seen with mirrors held still . Researchers also predicted a dynamical Casimir effect that can result when mirrors are moved, or objects otherwise undergo change. Now quantum physicist Pasi Lähteenmäki at Aalto University in Finland and his colleagues reveal that by varying the speed at which light can travel, they can make light appear from nothing.
The speed of light in a vacuum is constant, according to Einstein's theory of relativity, but its speed passing through any given material depends on a property of that substance known as its index of refraction. By varying a material's index of refraction, researchers can influence the speed at which both real and virtual photons travel within it. Lähteenmäki says one can think of this system as being much like a mirror, and if its thickness changes fast enough, virtual photons reflecting off it can receive enough energy from the bounce to turn into real photons. "Imagine you stay in a very dark room and suddenly the index of refraction of light [of the room] changes," Lähteenmäki says. "The room will start to glow."
The researchers began with an array of 250 superconducting quantum-interference devices, or SQUIDs—circuits that are extraordinarily sensitive to magnetic fields. They inserted the array inside a refrigerator. By carefully exerting magnetic fields on this array, they could vary the speed at which microwave photons traveled through it by a few percent. The researchers then cooled this array to 50 thousandths of a degree Celsius above absolute zero. Because this environment is supercold, it should not emit any radiation, essentially behaving as a vacuum. "We were simply studying these circuits for the purpose of developing an amplifier, which we did," says researcher Sorin Paraoanu, a theoretical physicist at Aalto University. "But then we asked ourselves—what if there is no signal to amplify? What happens if the vacuum is the signal?"
The investigators caution that such experiments do not constitute a magical way to get more energy out of a system than what is input. For instance, it takes energy to change a material's index of refraction. Instead, such research could help scientists learn more about the mysteries of quantum entanglement, which lies at the heart of quantum computers—advanced machines that could in principle run more calculations in an instant than there are atoms in the universe. The entangled microwave photons the experimental array generated "can be used for a form of quantum computation known as 'continuous variable' quantum information processing,” Girvin says. “This is a direction which is just beginning to open up.” Wilson adds that these systems “might be used to simulate some interesting scenarios. For instance, there are predictions that during cosmic inflation in the early universe, the boundaries of the universe were expanding nearly at light-speed or faster than the speed of light. We might predict there'd be some dynamical Casimir radiation produced then, and we can try and do tabletop simulations of this." So the static Casimir effect involves mirrors held still; the dynamical Casimir effect can for instance involve mirrors that move.
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Two young EPFL scientists have developed a device that can create 3D images of living cells and track their reaction to various stimuli without the use of contrast dyes or fluorophores.
In the world of microscopy, this advance is almost comparable to the leap from photography to live television. Two young EPFL researchers, Yann Cotte and Fatih Toy, have designed a device that combines holographic microscopy and computational image processing to observe living biological tissues at the nanoscale. Their research is being done under the supervision of Christian Depeursinge, head of the Microvision and Microdiagnostics Group in EPFL’s School of Engineering.
Using their setup, three-dimensional images of living cells can be obtained in just a few minutes – instantaneous operation is still in the works – at an incredibly precise resolution of less than 100 nanometers, 1000 times smaller than the diameter of a human hair. And because they’re able to do this without using contrast dyes or fluorescents, the experimental results don’t run the risk of being distorted by the presence of foreign substances.
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For the first time, physicists have found that humans can discriminate a sound's frequency (related to a note's pitch) and timing (whether a note comes before or after another note) more than 10 times better than the limit imposed by the Fourier uncertainty principle. Not surprisingly, some of the subjects with the best listening precision were musicians, but even non-musicians could exceed the uncertainty limit. The results rule out the majority of auditory processing brain algorithms that have been proposed, since only a few models can match this impressive human performance.
By ruling out many of the simpler models of auditory processing, the new results may help guide researchers to identify the true mechanism that underlies human auditory hyperacuity. Understanding this mechanism could have wide-ranging applications in areas such as speech recognition; sound analysis and processing; and radar, sonar, and radio astronomy. "You could use fancier methods in radar or sonar to try to analyze details beyond uncertainty, since you control the pinging waveform; in fact, bats do," Magnasco said. Building on the current results, the researchers are now investigating how human hearing is more finely tuned toward natural sounds, and also studying the temporal factor in hearing. "Such increases in performance cannot occur in general without some assumptions," Magnasco said. "For instance, if you're testing accuracy vs. resolution, you need to assume all signals are well separated. We have indications that the hearing system is highly attuned to the sounds you actually hear in nature, as opposed to abstract time-series; this comes under the rubric of 'ecological theories of perception' in which you try to understand the space of natural objects being analyzed in an ecologically relevant setting, and has been hugely successful in vision. Many sounds in nature are produced by an abrupt transfer of energy followed by slow, damped decay, and hence have broken time-reversal symmetry. We just tested that subjects do much better in discriminating timing and frequency in the forward version than in the time-reversed version (manuscript submitted). Therefore the nervous system uses specific information on the physics of sound production to extract information from the sensory stream. "We are also studying with these same methods the notion of simultaneity of sounds. If we're listening to a flute-piano piece, we will have a distinct perception if the flute 'arrives late' into a phrase and lags the piano, even though flute and piano produce extended sounds, much longer than the accuracy with which we perceive their alignment. In general, for many sounds we have a clear idea of one single 'time' associated to the sound, many times, in our minds, having to do with what action we would take to generate the sound ourselves (strike, blow, etc)." Delete the scoop?
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African physicists build the first laser with a beam that can be controlled and shaped digitally.
Physicists currently change the shape by placing various kinds of beam-shaping devices in front of the laser. These include lenses, mirrors and digital holograms generated using spatial light modulators. But because these devices are essentially bolted on to the front of a laser, they all require expensive custom optics that have to be calibrated each time they are changed.
Today, however, Sandile Ngcobo at the University of KwaZulu–Natal in South Africa and few buddies, say they’ve worked out a way round this. And they’ve designed and built a device to test their idea. The solution is simple. Instead of putting a spatial light modulator in front of the laser, they’ve built one in to the device, where it acts as the mirror at one end of the cavity. In this way, the spatial light modulator shapes the beam as it is being amplified.
The result is that the beam is already shaped in the required way when it emerges from the laser cavity. “We have demonstrated a novel digital laser that allows arbitrary intra-cavity laser beam shaping to be executed on the fly,” say Ngcobo and co.
The big advantage of all this is that the spatial light modulator generates patterns electronically. That allows these guys to change the beam shape at the touch of a button and without any of the time-consuming set up required with other methods.
They call their device a digital laser, because the beam can be shaped electronically with a computer. That’s the first time such a machine has been built.
The results are interesting. In putting the digital laser though it’s paces, they’ve shown how it can produce all kinds of beams with different shapes (see figure).
The applications are many. It will make various kinds of technologies much simpler, such as holographic laser tweezers and controlling aberrations in real time. Impressive stuff! Delete the scoop?
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A field that permeates the universe and gives rise to a new force, or "fifth force," between massive objects may be a candidate for dark energy and an explanation for why the expansion of the universe is accelerating. This field, called the symmetron field, is so named because it has a symmetry in regions of high density, while in regions of low density, such as a vacuum, the symmetry is broken and the field mediates the new force.
Currently, the symmetron concept is purely theoretical. But in a new study, physicist Amol Upadhye at Argonne National Laboratory in Argonne, Illinois, has calculated that a previously unexplored symmetron regime near the dark energy scale will give rise to a fifth force at submillimeter distances. He proposes that short-range gravity experiments can search for the fifth force at these distances and possibly reveal if dark energy is in fact a symmetron field. "Much of my work has focused on chameleon dark energy theories, and I really only started thinking about symmetrons last summer," Upadhye said. "Modern experimental techniques and technologies have advanced enough to search for new physics at distances of interest for dark energy theories." As Upadhye explained, a symmetron field could fulfill the role of dark energy by acting as a negative pressure. "Dark energy in general can be described by a constant (or slowly varying) vacuum energy density, such as that due to a field whose potential is minimized at a small, positive value," he said. "In the presence of such an energy density, Einstein's equation of General Relativity (GR) predicts that the universe will expand at an accelerating rate. In GR, pressure gravitates; positive pressures contribute to the decelerating expansion of the universe. Dark energy acts as a negative pressure which leads to an accelerating expansion.
"The simplest model of a dark energy is Einstein's cosmological constant, a constant vacuum energy density which explains all available data. The big question in cosmology is whether or not the dark energy is just a cosmological constant. Alternative theories predict that the vacuum energy density evolves with time, or that new ('fifth') forces exist between known particles. Delete the scoop?
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The first experimental observation of a quantum mechanical phenomenon that was predicted nearly 70 years ago holds important implications for the future of graphene-based electronic devices. Working with microscopic artificial atomic nuclei fabricated on graphene, a collaboration of researchers led by scientists with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley have imaged the "atomic collapse" states theorized to occur around super-large atomic nuclei.
"Atomic collapse is one of the holy grails of graphene research, as well as a holy grail of atomic and nuclear physics," says Michael Crommie, a physicist who holds joint appointments with Berkeley Lab's Materials Sciences Division and UC Berkeley's Physics Department. "While this work represents a very nice confirmation of basic relativistic quantum mechanics predictions made many decades ago, it is also highly relevant for future nanoscale devices where electrical charge is concentrated into very small areas." Crommie is the corresponding author of a paper describing this work in the journal Science. The paper is titled "Observing Atomic Collapse Resonances in Artificial Nuclei on Graphene." Co-authors are Yang Wang, Dillon Wong, Andrey Shytov, Victor Brar, Sangkook Choi, Qiong Wu, Hsin-Zon Tsai, William Regan, Alex Zettl, Roland Kawakami, Steven Louie, and Leonid Levitov.
Originating from the ideas of quantum mechanics pioneer Paul Dirac, atomic collapse theory holds that when the positive electrical charge of a super-heavy atomic nucleus surpasses a critical threshold, the resulting strong Coulomb field causes a negatively charged electron to populate a state where the electron spirals down to the nucleus and then spirals away again, emitting a positron (a positively–charged electron) in the process. This highly unusual electronic state is a significant departure from what happens in a typical atom, where electrons occupy stable circular orbits around the nucleus.
"Nuclear physicists have tried to observe atomic collapse for many decades, but they never unambiguously saw the effect because it is so hard to make and maintain the necessary super-large nuclei," Crommie says. "Graphene has given us the opportunity to see a condensed matter analog of this behavior, since the extraordinary relativistic nature of electrons in graphene yields a much smaller nuclear charge threshold for creating the special supercritical nuclei that will exhibit atomic collapse behavior." Perhaps no other material is currently generating as much excitement for new electronic technologies as graphene, sheets of pure carbon just one atom thick through which electrons can freely race 100 times faster than they move through silicon. Electrons moving through graphene's two-dimensional layer of carbon atoms, which are arranged in a hexagonally patterned honeycomb lattice, perfectly mimic the behavior of highly relativistic charged particles with no mass. Superthin, superstrong, superflexible, and superfast as an electrical conductor, graphene has been touted as a potential wonder material for a host of electronic applications, starting with ultrafast transistors. Delete the scoop?
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Researchers at the National Institute of Standards and Technology (NIST) have demonstrated a solid-state refrigerator that uses quantum physics in micro- and nanostructures to cool a much larger object to extremely low temperatures. What's more, the prototype NIST refrigerator, which measures a few inches in outer dimensions, enables researchers to place any suitable object in the cooling zone and later remove and replace it, similar to an all-purpose kitchen refrigerator. The cooling power is the equivalent of a window-mounted air conditioner cooling a building the size of the Lincoln Memorial in Washington, D.C.
"It's one of the most flabbergasting results I've seen," project leader Joel Ullom says. "We used quantum mechanics in a nanostructure to cool a block of copper. The copper is about a million times heavier than the refrigerating elements. This is a rare example of a nano- or microelectromechanical machine that can manipulate the macroscopic world."
The technology may offer a compact, convenient means of chilling advanced sensors below standard cryogenic temperatures—300 milliKelvin (mK), typically achieved by use of liquid helium—to enhance their performance in quantum information systems, telescope cameras, and searches for mysterious dark matter and dark energy. The NIST refrigerator's cooling elements, consisting of 48 tiny sandwiches of specific materials, chilled a plate of copper, 2.5 centimeters on a side and 3 millimeters thick, from 290 mK to 256 mK. The cooling process took about 18 hours. NIST researchers expect that minor improvements will enable faster and further cooling to about 100 mK.
The cooling elements are sandwiches of a normal metal, a 1-nanometer-thick insulating layer, and a superconducting metal. When a voltage is applied, the hottest electrons "tunnel" from the normal metal through the insulator to the superconductor. The temperature in the normal metal drops dramatically and drains electronic and vibrational energy from the object being cooled.
NIST researchers previously demonstrated this basic cooling method** but are now able to cool larger objects that can be easily attached and removed. Researchers developed a micromachining process to attach the cooling elements to the copper plate, which is designed to be a stage on which other objects can be attached and cooled. Additional advances include better thermal isolation of the stage, which is suspended by strong, cold-tolerant cords.
Cooling to temperatures below 300 mK currently requires complex, large and costly apparatus. NIST researchers want to build simple, compact alternatives to make it easier to cool NIST's advanced sensors. Researchers plan to boost the cooling power of the prototype refrigerator by adding more and higher-efficiency superconducting junctions and building a more rigid support structure. Delete the scoop?
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New results of a numerical search for periodic orbits of three equal masses moving in a plane under the influence of Newtonian gravity, with zero angular momentum have been found. A topological method is used to classify periodic three-body orbits into families, which fall into four classes, with all three previously known families belonging to one class. The classes are defined by the orbits geometric and algebraic symmetries. In each class the researchers present a few orbits initial conditions, 15 in all; 13 of these correspond to distinct orbits. Delete the scoop?
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A multi-university team of researchers has artificially engineered a unique multilayer material that could lead to breakthroughs in both superconductivity research and in real-world applications.
The researchers can tailor the material, which seamlessly alternates between metal and oxide layers, to achieve extraordinary superconducting properties - in particular, the ability to transport much more electrical current than non-engineered materials.
The team includes experts from the University of Wisconsin-Madison, Florida State University and the University of Michigan. Led by Chang-Beom Eom, the Harvey D. Spangler Distinguished Professor of materials science and engineering and physics at UW-Madison, the group described its breakthrough March 3, 2013, in the advance online edition of the journal Nature Materials.
Superconductors, which presently operate only under extremely cold conditions, transport energy very efficiently. With the ability to transport large electrical currents and produce high magnetic fields, they power such existing technologies as magnetic resonance imaging and Maglev trains, among others. They hold great potential for emerging applications in electronic devices, transportation, and power transmission, generation and storage.
Carefully layered superconducting materials are increasingly important in highly sophisticated applications. For example, a superconducting quantum interference device, or SQUID, used to measure subtle magnetic fields in magnetoencephalography scans of the brain, is based on a three-layer material.
However, one challenge in the quest to understand and leverage superconductivity is developing materials that work at room temperature. Currently, even unconventional high-temperature superconductors operate below -369 degrees Fahrenheit.
An unconventional high-temperature superconductor, the researchers' iron-based "pnictide" material is promising in part because its effective operating temperature is higher than that of conventional superconducting materials such as niobium, lead or mercury.
The research team engineered and measured the properties of superlattices of pnictide superconductors. A superlattice is the complex, regularly repeating geometric arrangement of atoms—its crystal structure—in layers of two or more materials. Pnictide superconductors include compounds made from any of five elements in the nitrogen family of the periodic table.
The researchers' new material is composed of 24 layers that alternate between the pnictide superconductor and a layer of the oxide strontium titanate. Creating such systems is difficult, especially when the arrangement of atoms, and chemical compatibility, of each material is very different. Yet, layer after layer, the researchers maintained an atomically sharp interface—the region where materials meet. Each atom in each layer is precisely placed, spaced and arranged in a regularly repeating crystal structure.
The new material also has improved current-carrying capabilities. As they grew the superlattice, the researchers also added a tiny bit of oxygen to intentionally insert defects every few nanometers in the material. These defects act as pinning centers to immobilize tiny magnetic vortices that, as they grow in strength in large magnetic fields, can limit current flow through the superconductor. "If the vortices move around freely, the energy dissipates, and the superconductor is no longer lossless," says Eom. "We have engineered both vertical and planar pinning centers, because vortices created by magnetic fields can be in many different orientations."
Eom sees possibilities for researchers to expand upon his team's success in engineering man-made superconducting structures. "There's a need to engineer superlattices for understanding fundamental superconductivity, for potential use in high-field and electronic devices, and to achieve extraordinary properties in the system," says Eom. "And, there is indication that interfaces can be a new area of discovery in high-temperature superconductors. This material offers those possibilities." Delete the scoop?
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“Ex-Nasa scientist seeks visionary billionaire to help change the world. High risk venture. Return not guaranteed. GSOH a plus.”
John Mankins, the scientist in question, has not yet reached the point of placing a classified ad, but it could soon be an option. The 25-year veteran of the US space agency is the man behind a project called SPS-Alpha, which aims to loft tens of thousands of lightweight, inflatable modules into space. Once there, they will be assembled into a huge bell-shaped structure that will use mirrors to concentrate energy from the sun onto solar panels. The collected energy would then be beamed down to ground stations on Earth using microwaves, providing unlimited, clean energy and overnight reducing our reliance on polluting fossil fuels. The snag? It is unproven technology and he estimates it will take at least $15 B - $20 B to get his project off the ground.
Mankins initially had research funding from an advanced concepts arm at Nasa, but that money dried up in September 2012; hence his continuing search for a benefactor. “I can't think of a better solution than to find somebody who is very wealthy, very visionary and willing to make this happen,” he says.
But not everyone shares Mankins' optimism. Space-based solar power (SBSP) is a topic that divides the scientific world into extremes. On one side are people like Mankins who believe it is the only solution to our ever increasing energy demands, whilst on the other is a sizeable chunk of the scientific community who believe any money put into solar power should remain firmly on the ground.
SBSP has its roots in the 1941 short story Reason, by Isaac Asimov, which depicts a space station – run by robots – collecting energy from the sun to distribute to Earth and other planets. No further thought was given to the idea until the late 1960s, when aerospace engineer Peter Glaser began to investigate its potential. In the following decades, various concepts were put forward but none took off. At the same timeNasa and the US Department of Energy also became involved, funding bits and pieces of research and commissioning reports into its feasibility. Most of these concluded that SBSP was too “high risk” and too costly.
But in recent years, SBSP has once again begun to attract attention with projects emerging in the US, Russia, China, India and Japan, amongst others. All are driven by increasing energy demands, soaring oil and gas prices, a desire to find clean alternatives to fossil fuels and by a burgeoning commercial space industry that promises to lower the cost of entry into space and spur on a host of new industries.
“SBSP is the ultimate energy source for the world and eventually it's going to replace nearly everything else,” says Ralph Nansen of US-based advocacy group Solar High, with some of the characteristic hyperbole that defines both sides of the SBSP debate. “I don't think there's any doubt that within the next century we will be getting the majority of our power from space. It's just a question of when.” Delete the scoop?
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MIT researchers' new method for observing the motion of electron density waves in a superconducting material led to the detection of two different kinds of variations in those waves: amplitude (or intensity) changes and phase changes, shifting the relative positions of peaks and troughs of intensity. These new findings could make it easier to search for new kinds of higher-temperature superconductors.
While the phenomenon of superconductivity — in which some materials lose all resistance to electric currents at extremely low temperatures — has been known for more than a century, the temperature at which it occurs has remained too low for any practical applications. The discovery of “high-temperature” superconductors in the 1980s — materials that could lose resistance at temperatures of up to negative 140 degrees Celsius — led to speculation that a surge of new discoveries might quickly lead to room-temperature superconductors. Despite intense research, these materials have remained poorly understood.
Mercor's curator insight,
February 25, 11:59 AM
Scooped by Dr. Stefan Gruenwald onto Amazing Science Delete the scoop?
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Imagine a cell phone charger that recharges your phone remotely without even knowing where it is; a device that targets and destroys tumors, wherever they are in the body; or a security field that can disable electronics, even a listening device hiding in a prosthetic toe, without knowing where it is. The figure shown demonstrates secure communication with nonlinear time-reversal of two different UMD images using electromagnetic waves (signals) each sent through a complicated wave scattering environment (brown box in the middle). The black boxes represent time-reversed signals that are not reconstructed after being scattered. "If you go toward a secure building, they won't let you take cell phones," Frazier says, "So instead of checking everyone, they could detect the cell phone and send a lot of energy to to jam it." What differentiates this research from other time-reversal projects, such as underwater communication, is that it focuses on nonlinear objects such as a cellphone, diode or even a rusty piece of metal. When the altered, nonlinear frequency of nonlinear objects is recorded, time-reversed and retransmitted, it creates a private communication channel, because other objects cannot understand the signal. Delete the scoop?
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When matter is compressed beyond a certain density, a black hole is created. It is called black because no light can escape from it. Some black holes are the tombstones of what were once massive stars. An enormous black hole is thought to lurk at the center of the Milky Way galaxy.
All the mass of a black hole is concentrated into a point at its center called the singularity. Gravity surrounding the singularity is so strong, you would have to travel faster than light to escape. This creates a spherical zone surrounding the singularity called the event horizon from which nothing can escape.
At about one and a half times the diameter of the event horizon, photons become trapped in circular orbits around the black hole. All the mass of a black hole is concentrated into a point at its center called the singularity.
Gravity surrounding the singularity is so strong, you would have to travel faster than light to escape. This creates a spherical zone surrounding the singularity called the event horizon from which nothing can escape.
In theory, a black hole of any size could exist. A black hole with the mass of our sun would be 3.7 miles (6 km) in diameter. In practice, the death of a star like the sun does not compress the material enough to form a black hole. Stars with about two times the sun’s mass or more form black holes.
Astronomers recognize two major types. Stellar-mass black holes have the mass of several sun-sized stars. They form when a dying star explodes in a supernova, then collapses under its own gravity. Matter drawn toward the black hole forms an accretion disc.
Supermassive black holes can have billions of times our sun’s mass. Matter drawn toward a supermassive black hole is compressed, heats up and may be blasted out into jets thousands of light-years long.
Stellar-mass black holes are scattered throughout the galaxy. A supermassive black hole lies at the core of many galaxies, including our own. The Milky Way’s supermassive black hole is called SgrA* (Sagittarius A-star), and it is seen from Earth in the constellation Sagittarius. The supermassive black hole is about 26,000 light-years away, and has a mass of at least 4 million times the mass of our sun.
The powerful gravity of a black hole distorts light, space and time. One effect is gravitational lensing. A black hole between us and a distant galaxy will bend the rays of light, causing our view of the galaxy to be warped. We have yet to photograph a black hole in detail, but simulations suggest that the supermassive black hole at the Milky Way’s center might appear to be a distorted crescent. Delete the scoop?
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Researchers from the University of Bordeaux in Franceused high-frequency sound waves to test the stiffness and viscosity of the nuclei of individual human cells to help answer questions such as how cells adhere to medical implants and why healthy cells turn cancerous.
“We have developed a new non-contact, non-invasive tool to measure the mechanical properties of cells at the sub-cell scale,” says Bertrand Audoin, a professor in the mechanics laboratory at the University of Bordeaux. “This can be useful to follow cell activity or identify cell disease.”
The technique, called picosecond ultrasonics, was initially developed to measure the thickness of semiconductor chip layers.
The researchers grew cells on a metal plate and then flashed the cell-metal interface with an ultra-short laser pulse to generate high-frequency sound waves. Another laser measured how the sound pulse propagated through the cells, giving the scientists clues about the mechanical properties of the individual cell components.
“The higher the frequency of sound you create, the smaller the wavelength, which means the smaller the objects you can probe” says Audoin. “We use gigahertz waves, so we can probe objects on the order of a hundred nanometers.” For comparison, a cell’s nucleus is about 10,000 nanometers wide.
In the coming years, the team envisions studying cancer cells with sound. “A cancerous tissue is stiffer than a healthy tissue,” notes Audoin. “If you can measure the rigidity of the cells while you provide different drugs, you can test if you are able to stop the cancer at the cell scale.” 
Katie Johnson's curator insight,
April 30, 2:23 PM
This article shows the different kinds of work ultra sounds can be used for, not just in pregnancy and other normal cases. It shows the variety of things I could be doing while on the job. Delete the scoop?
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Thanks to the strange laws of quantum mechanics, quantum computers would be able to carry out certain computational tasks much faster than conventional computers. Among the most promising technologies for the construction of a quantum computer are systems of single atoms, confined in so-called ion traps and manipulated with lasers. In the laboratory, these systems have already been used to test key building blocks of a future quantum computer. “Currently, we can carry out successful quantum computations with atoms,” explain Andreas Stute and Bernardo Casabone, both PhD students at the University of Innsbruck’s Institute for Experimental Physics. “But we are still missing viable interfaces with which quantum information can be transferred over optical channels from one computer to another.”
The University of Innsbruck physicists first trap a single calcium ion in an ion trap and position it between two highly reflective mirrors. “We use a laser to write the desired quantum information onto the electronic states of the atom,” explains Stute. “The atom is then excited with a second laser, and as a result, it emits a photon. At this moment, we write the atom’s quantum information onto the polarization state of the photon, thus mapping it onto the light particle.” The photon is stored between the mirrors until it eventually flies out through one mirror, which is less reflective than the other. “The two mirrors steer the photon in a specific direction, effectively guiding it into an optical fiber,” says Casabone. The quantum information stored in the photon could thus be conveyed over the optical fiber to a distant quantum computer, where the same technique could be applied in reverse to write it back onto an atom. 
Nicholas John Whittred's comment,
March 22, 2:39 AM
If the internet is to harness the power of quantum computers data will have to be transferred via photons.
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Dean Keith Simonton, a psychology professor at the University of California, has published a comment piece in the journal Nature, where he argues that it's unlikely mankind will ever produce another Einstein, Newton, Darwin, etc. This is because, he says, we've already discovered all the most basic ideas that describe how the natural world works. Any new work, will involve little more than adding to our knowledge base. Simonton could be wrong of course – there might yet be some person that looks at all that has been discovered and compares it with his or her own observations, and finds that what we think we know, is completely wrong, and offers evidence of something truly groundbreaking as an alternative. The study of astrophysics, for example, appears ripe for a new approach. Scientists are becoming increasingly frustrated in trying to explain why the universe is not just expanding, but is doing so at an increasing rate. Perhaps most of the theories put forth over the past half-century or so, are completely off base. Modern science can't even explain gravity, after all. Isn't it possible that there is something at work that will need the intelligence, insight and courage of an Einstein to figure out? It appears we as a species are counting on it, even as we wonder if it's even possible. Delete the scoop?
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A team including School of Physics PhD students James Colless, Alice Mahoney and John Hornibrook, and Associate Professor Andrew Doherty and Associate Professor David Reilly, with two scientists from the University of California, Santa Barbara, have found a new way of detecting charge on the quantum dots using the gate electrodes already in the system.
"Previously, sensitive electrometers which measure minute charges were used to read-out the electron state on quantum dots. These work well, but they are somewhat separate devices built onto the ends of the quantum dot system. They are a bit like having microphones nearby that can pick up the sound of electrons," explained Associate Professor Reilly.
"What we have shown is that the gates or electrodes that are already in place to create the quantum dot in the first place, can also act as read-out detectors. This means you don't need separate devices and you don't need to worry about how to place those separate electrometer devices."
"Whereas the old system was like having microphones nearby to detect sound, our new system could be likened to using the walls of a room as in-built microphones - you don't need separate microphones for every room of the house, just use the walls as microphones," said Associate Professor Reilly.
"Our new method makes the whole quantum system easier to build and use, as adding nanoscale electrometers for every quantum dot in a million-dot-array is a hard problem. By using the electrodes already in the system, we've found an efficient new way to measure charge in the big quantum systems of the future."
The new method of detection allows for read-out in large dot arrays with no limitation on the size of the array for the read-out method to work. James Colless, whose PhD research contributed greatly to the finding, said, "The technologies that we are developing are part of a global research effort to advance the prospect of quantum computing. In a similar way to how billions of transistors can now be placed on a single silicon computer chip, in the future we would like to engineer semiconductor chips containing huge numbers of interacting quantum two-level systems - called qubits. The work presented in this paper suggests a new method of reading out qubits that enables this goal." Delete the scoop?
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