Friday, April 11, 2014

A Mathematical Proof That The Universe Could Have Formed Spontaneously From Nothing — The Physics arXiv Blog — Medium

A Mathematical Proof That The Universe Could Have Formed Spontaneously From Nothing — The Physics arXiv Blog — Medium: The new proof is based on a special set of solutions to a mathematical entity known as the Wheeler-DeWitt equation...

In each of these cases, they find a solution in which the bubble can expand exponentially and thereby reach a size in which a universe can form—a Big Bang...

Thursday, April 10, 2014

This Could Be the First Animal to Live Entirely Inside a Computer

This Could Be the First Animal to Live Entirely Inside a Computer: "Our project is to simulate as much of the important physics — or biophysics — of the C. elegans as we can, and then compare against measurements from real worms. When we say simulation, we are specifically referring to writing computer programs that use equations from physics that are applied to what we know about the worm..."

"We are currently addressing the challenge of closing the 'brain-behavior loop' in C. elegans," he says. "In other words, through this simulation we want to understand how its proto-brain controls its muscles to move its body around an environment, and then how the environment is interpreted by the proto-brain. That means leaving aside reproduction or digestion or other internal functions for now until that first part is complete. Once we get there, we will move on to these other aspects.

LHC spots particle that may be new form of matter - physics-math - 10 April 2014 - New Scientist

LHC spots particle that may be new form of matter - physics-math - 10 April 2014 - New Scientist: Now that Z(4430)'s existence is confirmed, the next challenge is to work out whether it really is a tetraquark.

There is at least one reason why physicists can be hopeful. The other suspected tetraquarks might simply be loosely bound pairs of mesons, says Marek Karliner, a theorist at Tel Aviv University in Israel, who was not part of the team. Z(4430) is different because its mass does not seem to allow for this.

Wednesday, April 9, 2014

New ‘switch’ could power quantum computing | MIT News Office

New ‘switch’ could power quantum computing | MIT News Office:  “We have demonstrated basically an atom can switch the phase of a photon. And the photon can switch the phase of an atom...”

In this case, the researchers used a laser to place a rubidium atom very close to the surface of a photonic crystal cavity, a structure of light. The atoms were placed no more than 100 or 200 nanometers — less than a wavelength of light — from the edge of the cavity. At such small distances, there is a strong attractive force between the atom and the surface of the light field, which the researchers used to trap the atom in place...

“In some sense, it was a big surprise how simple this solution was compared to the different techniques you might envision of getting the atoms there,” Vuletić says.

Monday, April 7, 2014

How to create a large-area visible-light invisibility cloak | KurzweilAI

How to create a large-area visible-light invisibility cloak | KurzweilAI: To create the material, they used a nanotransfer printing technique that creates metal/dielectric composite films. These are stacked in a 3-D architecture to achieve nanoscale patterns for operation in the visible spectral range. Control of electromagnetic resonances over the 3-D space by structural manipulation allows precise control over propagation of light...

...he sample they created covers about 4 square centimeters...

Friday, April 4, 2014

How the U.S. Built the World’s Most Ridiculously Accurate Atomic Clock | Science | WIRED

How the U.S. Built the World’s Most Ridiculously Accurate Atomic Clock | Science | WIRED: Both NIST-F2 and the standard it replaces, NIST-F1, are known as cesium-based atomic fountain clocks...

The previous generation of atomic clock was already quite good at figuring out the length of a second but had a few small sources of error. NIST-F1 operates at room temperature and so the walls of the chamber in which the cesium atom ball is tossed heat up, emitting a small amount of radiation. This interferes with the atoms, causing them to shift ever so slightly in their energy levels. By cooling NIST-F2 with liquid nitrogen, the new timepiece reaches temperatures of – 316 degrees Fahrenheit, virtually eliminating this excess radiation and reducing the shifting 100-fold.

Wednesday, April 2, 2014

A bound on the natural width of the Higgs boson

A bound on the natural width of the Higgs boson: In the Standard Model, the Higgs boson is expected to be very narrow: its width is roughly 4 MeV, a good 30,000 times smaller than the central mass of approximately 125 GeV...

The width is usually determined from the distribution of masses observed. In this case, however, the expected width is much smaller than the experimental resolution of the mass measurement...

A quantitative analysis leads to an upper bound on the Higgs width of ~4 times that of the Standard Model value, approximately 17 MeV. This is a huge improvement, of a factor of 200 over the previous bound.

Sunday, March 30, 2014

The Astounding Link Between the P≠NP Problem and the Quantum Nature of Universe — The Physics arXiv Blog — Medium

The Astounding Link Between the P≠NP Problem and the Quantum Nature of Universe — The Physics arXiv Blog — Medium: ...He says the key is to think of Schrodinger’s cat as a problem of computational complexity theory...

...He says there is an implicit assumption when physicists say that Schrödinger’s equation can describe macroscopic systems. This assumption is that the equations can be solved in a reasonable amount of time to produce an answer...

If P ≠ NP and there is no efficient algorithm for solving Schrödinger’s equation, then there is only one way of finding a solution, which is a brute force search...

So the number of elementary operations needed to exactly solve this equation would be equal to 2^10^24...

...this time scale is considerably shorter than the Planck timescale, which is roughly equal to 10^-43 seconds.

Friday, March 28, 2014

Hypnotic Art Shows How Patterns Emerge From Randomness in Nature | Science | WIRED

Hypnotic Art Shows How Patterns Emerge From Randomness in Nature | Science | WIRED: Turing called this the reaction-diffusion process, meaning that it’s driven by reactive molecules that can diffuse between cells. He called these molecules “morphogens”...

...a team of scientists based at Brandeis University reproduced the system Turing envisioned...

If Turing’s theory was right, then the population of cells would ultimately assume one of six different patterns...

In fact, this is mostly what the team found — they saw five of the six predicted patterns; but they also found a seventh pattern that Turing had not predicted....

Wednesday, March 26, 2014

How To Build A Quantum Telescope — Medium

How To Build A Quantum Telescope — MediumHer idea is to use the astrophysical photons to stimulate the production of an entangled pair, inside a telescope. The first of this pair then hits the detector, generating an image. But the other can be used to increase the information known about the first, thereby increasing the resolution and beating the diffraction limit.

Tuesday, March 25, 2014

Cosmologists cast doubt on inflation evidence

Cosmologists cast doubt on inflation evidence: Inflation may very well be the cause—and Dent and company state right off the bat that "there is little doubt that inflation at the Grand Unified Scale is the best motivated source of such primordial waves" –  but there's also a possibility, however remote, that some other, later cosmic event is responsible for at least some if not all of the BICEP2 measurements.

Sunday, March 23, 2014

Engineers design ‘living materials’ | MIT News Office

Engineers design ‘living materials’ | MIT News Office: By programming cells to produce different types of curli fibers under certain conditions, the researchers were able to control the biofilms’ properties and create gold nanowires, conducting biofilms, and films studded with quantum dots...

“It’s a really simple system but what happens over time is you get curli that’s increasingly labeled by gold particles. It shows that indeed you can make cells that talk to each other and they can change the composition of the material over time,” Lu says. “Ultimately, we hope to emulate how natural systems, like bone, form. No one tells bone what to do, but it generates a material in response to environmental signals.”

Friday, March 21, 2014

Zuckerberg, Musk, and Kutcher Want to Build You a New Brain | Enterprise | WIRED

Zuckerberg, Musk, and Kutcher Want to Build You a New Brain | Enterprise | WIRED: ...a $40 million investment in a new kind of artificial intelligence called Vicarious...

Vicarious co-founder Dileep George previously built a similar company called Numenta...

This is the second big funding round for Vicarious, and it was lead by venture capital outfit Formation 8. The first $15 million round included investments by Facebook and Asana co-founder Dustin Moskovitz; former Facebook CTO and Quora founder Adam D’Angelo; PayPal and Palantir co-founder Peter Thiel; and Palantir co-founder Joe Lonsdale.

Graphene superconducting property discovered | KurzweilAI

Graphene superconducting property discovered | KurzweilAI: Scientists at... SLAC... have discovered how graphene... is superconducting in a graphene-calcium compound...

While it’s been known for nearly a decade that this combined material is superconducting, the new study offers the first compelling evidence that the graphene layers are instrumental in this process...

Researchers used a beam of intense ultraviolet light to look deep into the electronic structure of CaC6.

The purity of the sample combined with the high quality of the ultraviolet light beam allowed them to see deep into the material and distinguish what the electrons in each layer were doing, revealing details of their behavior that had not been seen before.

Thursday, March 20, 2014

Cosmologists Say Last Week’s Announcement About Gravitational Waves and Inflation May Be Wrong — The Physics arXiv Blog — Medium

Cosmologists Say Last Week’s Announcement About Gravitational Waves and Inflation May Be Wrong — The Physics arXiv Blog — Medium: Many cosmologists think that the same kind of phases changes occurred in the universe after inflation. Each phase change began in different regions at slightly different times...

This self-ordering process would have been hugely violent, generating its own gravitational waves that rippled through spacetime, albeit after inflation. Could this process be responsible for the polarisation that the BICEP2 team has measured?...

...a small improvement in the data could firmly rule out self-ordering as the origin of the signal.

Pseudogap theory puts physicists closer to high temperature superconductors

Pseudogap theory puts physicists closer to high temperature superconductors: The theory explains the transition phase to superconductivity, or "pseudogap" phase, which is one of the last obstacles to developing the next generation of superconductors and one of the major unsolved problems of theoretical condensed matter physics...

This new study found that YBa2Cu3O6+x oscillates between two quantum states during the pseudogap, one of which involves charge-density wave fluctuations. These periodic fluctuations in the distribution of the electrical charges are what destabilize the superconducting state above the critical temperature.

Wednesday, March 19, 2014

First glimpse of big bang ripples from universe's birth - physics-math - 17 March 2014 - New Scientist

First glimpse of big bang ripples from universe's birth - physics-math - 17 March 2014 - New Scientist: Inflation should have stretched the very first gravitational waves created during the big bang, taking them from imperceptible wavelengths to a size we can detect in the CMB... Rippling gravitational waves would subtly change the polarisation pattern, twisting the CMB into distinctive swirls called B-modes...

"We see a big excess of power, and it looks exactly like the gravitational wave signal that we had been seeking," says Pryke. "There's a huge zoo of inflationary models, but if we look at the simplest ones, they would predict values in the ballpark that we're seeing..."

"If gravity were not quantised, inflation would not produce gravitational waves," says Guth.

Meet The Physicist Who's Building Snake Robots | Popular Science

Meet The Physicist Who's Building Snake Robots | Popular Science: No one has ever studied the complexities of a sidewinder rattlesnake’s movement on sand, its natural substrate. In principle, you can understand how a hummingbird stays aloft or how a shark swims by solving fluid-dynamics equations. We don’t yet have fundamental equations for complex terrain—sand, leaf litter, tree bark. To figure that out, we built giant sandboxes that are equipped with high-speed cameras and can tilt to mimic dunes.

Tuesday, March 18, 2014

Scientists open a new window into quantum physics with superconductivity in LEDs

Scientists open a new window into quantum physics with superconductivity in LEDs: When a layer of such superconducting material is placed in close contact with a semiconductor LED structure, Cooper pairs are injected in to the LED, so that pairs of entangled electrons create entangled pairs of photons. The effect, however, turns out to work only in LEDs which use nanometre-thick active regions – quantum wells.

Monday, March 17, 2014

How An Ordinary Camera Phone Can Photograph Objects Hidden Behind Other Things — The Physics arXiv Blog — Medium

How An Ordinary Camera Phone Can Photograph Objects Hidden Behind Other Things — The Physics arXiv Blog — Medium: The trick here is to treat the data from each pixel as a separate image. The task then is to look for the correlation between each of these images, just as in the single-pixel imaging techniques...

And they even produce images using reflected light (as opposed to transmitting light). To prove this, these guys recorded the light from an object that was scattered off a wall covered in white paint.

Sure enough, the resulting image revealed the object, even though it was essentially around a corner from the camera.

Why I Still Doubt Inflation, in Spite of Gravitational Wave Findings | Cross-Check, Scientific American Blog Network

Why I Still Doubt Inflation, in Spite of Gravitational Wave Findings | Cross-Check, Scientific American Blog Network: ...inflation comes in so many different versions that it can give you “anything you want.” In other words, it cannot be falsified...

But here is what I’d like to see: First, corroboration of the BICEP2 findings by other groups and observatories. Second, experiments from high-energy physics that provide some sort of corroborating evidence of the driving mechanism of inflation. Third, an explanation of why the Alice’s Restaurant Problem isn’t still a problem. Fourth, an explanation of why only inflation, and not other more conventional physical phenomena, can account for the gravity-wave findings...

Saturday, March 15, 2014

Billionaires With Big Ideas Are Privatizing American Science - NYTimes.com

Billionaires With Big Ideas Are Privatizing American Science - NYTimes.com: Many of the patrons, they say, are ignoring basic research — the kind that investigates the riddles of nature and has produced centuries of breakthroughs, even whole industries — for a jumble of popular, feel-good fields like environmental studies and space exploration.

Thursday, March 13, 2014

Robot elephant trunk learns motor skills like a baby - tech - 13 March 2014 - New Scientist

Robot elephant trunk learns motor skills like a baby - tech - 13 March 2014 - New Scientist: The design showed that a trunk formed of 3D-printed segments can be controlled by an array of pneumatic artificial muscles...

They used a process called "goal babbling"... the robot remembers what happens to the trunk's position when tiny changes are made to the pressure in the thin pneumatic tubes feeding the artificial muscles. This creates a map that relates the trunk's precise position to the pressures in each tube.

The trunk can now be manually forced into a series of positions and learn to adopt them on command...

Tuesday, March 11, 2014

Orbital computing: An amazing atomic-level tech for future computers | ExtremeTech

Orbital computing: An amazing atomic-level tech for future computers | ExtremeTech: He calls the idea “orbital computing” since the bit... would be the orbits of electrons around the nucleus of an atom. The goal is to be able to probe the electron clouds of single atoms using terahertz waves of just the right size.

In materials like these, the macroscopic properties (like conductance) are controlled mainly by electron orbits known as “d-orbitals.” The state of these d-orbitals can be readily observed with X-rays, and they can be controlled as easily as adjusting the temperature. But temperature or other gross manipulations are relatively slow ways to try to read or write data, compact bunches of T-rays does the trick much better.

Acoustic Cloaking Device Hides Objects from Sound | Duke Pratt School of Engineering

Acoustic Cloaking Device Hides Objects from Sound | Duke Pratt School of Engineering

The acoustic cloaking device works in all three dimensions, no matter which direction the sound is coming from or where the observer is located...

In the case of the new acoustic cloak, the materials manipulating the behavior of sound waves are simply plastic and air. Once constructed, the device looks like several plastic plates with a repeating pattern of holes poked through them stacked on top of one another to form a sort of pyramid...

Monday, March 10, 2014

A black hole in a bath: Big physics on a bench-top - physics-math - 10 March 2014 - New Scientist

A black hole in a bath: Big physics on a bench-top - physics-math - 10 March 2014 - New Scientist

Supersymmetry...  One of its central predictions is that there should be more than one Higgs particle... they might have found some clue as to where those extra particles might be – in superfluid helium-3... The discovered Higgs weighs in at around 125 gigaelectronvolts (GeV). Studying the spectrum of excitations in the superfluid helium suggests Higgs particles should also exist at energies of 210 GeV and 325 GeV. These possibilities are not excluded by results collected so far at the LHC...

By concentrating laser light into a very small spot within a waveguide made of a glass block, he can temporarily change the refractive index of the glass so that it slows down subsequent laser pulses and ultimately repels them. "What makes these analogue experiments so powerful is that from a photon or a water wave's perspective, it has no way of distinguishing whether it is crossing the event horizon of a real black hole or is in a waveguide under some weird constraints," he says.

Wednesday, March 5, 2014

First step towards 'programmable materials'

First step towards 'programmable materials': The working model used by the researchers consists of a one-meter by one-centimeter aluminum plate that is one millimeter thick. This sheet-metal strip can vibrate at different frequencies. In order to control the wave propagation, ten small aluminum cylinders (7 mm thick, 1 cm high) are attached to the metal. Between the sheet and the cylinders sit piezo discs, which can be stimulated electronically and change their thickness in a flash. This ultimately enables the team headed by project supervisor Andrea Bergamini to control exactly whether and how waves are allowed to propagate in the sheet-metal strip. The aluminum strip thus turns into a so-called adaptive phononic crystal – a material with adaptable properties.

Tuesday, March 4, 2014

Team models photosynthesis and finds room for improvement

Team models photosynthesis and finds room for improvement: "We've modeled the whole system, and added all the components in a cyanobacterial system one at a time to our computer simulation to see if they give us an advantage."

The team found that some of the carboxysome genes hindered, while others greatly enhanced photosynthetic efficiency in crop plants such as soybean, rice and cassava...

"And if we put in about eight components of the carboxysome system, the model says that we could get a 60 percent increase in photosynthesis," he said.

Monday, March 3, 2014

Standard-Candle Supernovae are Still Standard, but Why? � Berkeley Lab News Center

Standard-Candle Supernovae are Still Standard, but Why? � Berkeley Lab News Center: ... a new analysis of normal Type Ia supernovae... shows that in fact they have a range of masses. Most are near or slightly below the Chandrasekhar mass, and about one percent somehow manage to exceed it...

A supernova eruption thoroughly trashes its white dwarf progenitor, so the most practical way to tell how much stuff was in the progenitor is by spectrographically “weighing” the leftover debris, the ejected mass...

The SNfactory team compared masses and other factors with light curves: the shape of the graph, whether narrow or wide, that maps how swiftly a supernova achieves its brightest point, how bright it is, and how hastily or languorously it fades away. The typical method of “standardizing” Type Ia supernovae is to compare their light curves and spectra....

“The conventional wisdom holds that the light curve width is determined primarily or exclusively by the nickel-56 mass,” Scalzo says, “whereas our results show that there must also be a deep connection with the ejected mass, or between the ejected mass and the amount of nickel-56 created in a particular supernova.”

Prime number enigma could be solved by simple networks - physics-math - 03 March 2014 - New Scientist

Prime number enigma could be solved by simple networks - physics-math - 03 March 2014 - New Scientist:

To investigate, Marián Boguñá of the University of Barcelona, Spain, and his colleagues turned the numbers from 2 to 1 billion into a network by linking composites to their prime building blocks. They also devised a way to generate similar networks using other simple rules to link the numbers, and wondered if they could get these networks to reproduce the pattern of links between primes and composites.

Their rules depend on probabilities, so the generated networks are different each time. On average, the researchers found that the webs are very close to the real network of primes and composites...

Tuesday, February 25, 2014

Scientists twist sound with metamaterials

Scientists twist sound with metamaterials: ...the team reports a simple design for a device, called an acoustic field rotator, which can twist wavefronts inside it so that they appear to be propagating from another direction...

Another surprise the team discovered was that acoustic and electromagnetic rotators can be designed based on the same principles. In this case, the researchers used anisotropic metamaterials, which possess physical properties that differ along different directions.


Thursday, February 20, 2014

Spinning Yarn Into Muscles | Science/AAAS | News

Spinning Yarn Into Muscles | Science/AAAS | News: Baughman, along with colleagues in Texas, Australia, and China, twisted plastic fibers and threads into yarns. Then when they applied heat, they found that the yarns contracted by up to 50%, a result they report today in Science. And cooling the plastic muscles returns them to their original length. Natural muscles, by comparison, only contract by 20%. Twisting together a bundle of polyethylene fishing lines, whose total diameter is only about 10 times larger than a human hair, produces a coiled polymer muscle that can lift 7.2 kilograms, the team found. Operated in parallel, an arrangement that increases their power and is similar to the way natural muscles are configured, a hundred of these polymer muscles could lift about 725 kilograms, Baughman says. Producing this force requires only off-the-shelf materials that cost about $5 per kilogram.

Tuesday, February 18, 2014

After 400 years, mathematicians find a new class of solid shapes

After 400 years, mathematicians find a new class of solid shapes: During the imagined bulging process, even one that involves replacing the bulge with multiple hexagons, as Craven points out, there will be formation of internal angles. These angles formed between lines of the same faces – referred to as dihedral angle discrepancies – means that, according to Schein and Gayed, the shape is no longer a polyhedron. Instead they claimed to have found a way of making those angles zero, which makes all the faces flat, and what is left is a true convex polyhedron...

Thursday, February 13, 2014

Superconductivity in orbit: Scientists find new path to loss-free electricity

Superconductivity in orbit: Scientists find new path to loss-free electricity: "For the first time, we obtained direct experimental evidence of the subtle changes in electron orbitals by comparing an unaltered, non-superconducting material with its doped, superconducting twin," said Brookhaven Lab physicist and project leader Yimei Zhu...

The Brookhaven researchers used a technique called quantitative convergent beam electron diffraction (CBED) to reveal the orbital clouds with subatomic precision...

The researchers first examined the electron clouds of non-superconducting samples of barium iron arsenic. The CBED data revealed that the arsenic atoms—placed above and below the iron in a sandwich-like shape (see image)—exhibited little shift or polarization of valence electrons. However, when the scientists transformed the compound into a superconductor by doping it with cobalt, the electron distribution radically changed.

Wednesday, January 29, 2014

Physicists create synthetic magnetic monopole predicted more than 80 years ago

Physicists create synthetic magnetic monopole predicted more than 80 years ago: Hall's team adopted an innovative approach to investigating Dirac's theory, creating and identifying synthetic magnetic monopoles in an artificial magnetic field generated by a Bose-Einstein condensate, an extremely cold atomic gas tens of billionths of a degree warmer than absolute zero. The team relied upon theoretical work published by Möttönen and his student Ville Pietilä that suggested a particular sequence of changing external magnetic fields could lead to the creation of the synthetic monopole...

...the team was rewarded with photographs that confirmed the monopoles' presence at the ends of tiny quantum whirlpools within the ultracold gas...

Friday, January 24, 2014

Stephen Hawking: 'There are no black holes' : Nature News & Comment

Stephen Hawking: 'There are no black holes' : Nature News & Comment: Now Hawking proposes a third, tantalizingly simple, option. Quantum mechanics and general relativity remain intact, but black holes simply do not have an event horizon to catch fire. The key to his claim is that quantum effects around the black hole cause space-time to fluctuate too wildly for a sharp boundary surface to exist.

In place of the event horizon, Hawking invokes an “apparent horizon”, a surface along which light rays attempting to rush away from the black hole’s core will be suspended. In general relativity, for an unchanging black hole, these two horizons are identical, because light trying to escape from inside a black hole can reach only as far as the event horizon and will be held there, as though stuck on a treadmill. However, the two horizons can, in principle, be distinguished. If more matter gets swallowed by the black hole, its event horizon will swell and grow larger than the apparent horizon.

Publishers withdraw more than 120 gibberish papers : Nature News & Comment

Publishers withdraw more than 120 gibberish papers : Nature News & Comment:

Over the past two years, computer scientist Cyril Labbé of Joseph Fourier University in Grenoble, France, has catalogued computer-generated papers that made it into more than 30 published conference proceedings between 2008 and 2013...

Labbé developed a way to automatically detect manuscripts composed by a piece of software called SCIgen, which randomly combines strings of words to produce fake computer-science papers...

Most of the conferences took place in China, and most of the fake papers have authors with Chinese affiliations...

 His detection technique, described in a study1 published in Scientometrics in 2012, involves searching for characteristic vocabulary generated by SCIgen...

Labbé emphasizes that the nonsense computer science papers all appeared in subscription offerings. In his view, there is little evidence that open-access publishers — which charge fees to publish manuscripts — necessarily have less stringent peer review than subscription publishers.

Thursday, January 16, 2014

The symphony of life, revealed - News Center

The symphony of life, revealed - News Center: Using a technique they developed based on terahertz near-field microscopy, scientists... have for the first time observed in detail the vibrations of lysozyme, an antibacterial protein found in many animals.

The team found that the vibrations, which were previously thought to dissipate quickly, actually persist in molecules like the “ringing of a bell...”

To observe the protein vibrations, Markelz’ team relied on an interesting characteristic of proteins: The fact that they vibrate at the same frequency as the light they absorb...

Markelz and her colleagues exposed a sample to light of different frequencies and polarizations, and measured the types of light the protein absorbed.

Thursday, January 9, 2014

First light-bending calculator designed with metamaterials - physics-math - 09 January 2014 - New Scientist

First light-bending calculator designed with metamaterials - physics-math - 09 January 2014 - New Scientist: The metamaterial computer works because light waves can draw mathematical curves in space, akin to a graph. In calculus, differentiation describes the slope of that curve at various points, while integration gives the area under the curve.

The team's metamaterial block can perform these calculations by modifying the light wave's profile. For example, if you shine a light wave describing a parabola (which corresponds to the equation y = x2) into a metamaterial that computes differentiation, it will come out the other side looking like a straight line described by y = 2x.siu

Monday, January 6, 2014

RAMBO allows high-magnetic-field experiments on a tabletop

RAMBO allows high-magnetic-field experiments on a tabletop: "We can literally see the sample inside the magnet," Kono said. "We have direct optical access, whereas if you go to a national high magnetic field facility, you have a monster magnet, and you can only access the sample through a very long optical fiber. You cannot do any nonlinear or ultrafast optical spectroscopy...

Kono's group built the system to analyze very small, if not microscopic, samples. A sample plate sits on a long sapphire cylinder that passes through the coil's container and juts through one end of the magnet to place it directly in the center of the magnetic field.

The cylinder provides one direct window to the experiment; a port on the other side of the container looks directly down upon the sample. The coil is bathed in liquid nitrogen to keep it cool at around 80 kelvins (-315 degrees Fahrenheit). The sample temperature can be independently controlled from about 10 K to room temperature by adjusting the flow of liquid helium to the sapphire cylinder.

Friday, January 3, 2014

Supercomputers join search for 'cheapium'

Supercomputers join search for 'cheapium': The identification of the new platinum-group compounds hinges on databases and algorithms that Curtarolo and his group have spent years developing. Using theories about how atoms interact to model chemical structures from the ground up, Curtarolo and his group screened thousands of potential materials for high probabilities of stability. After nearly 40,000 calculations, the results identified 37 new binary alloys in the platinum-group metals, which include osmium, iridium ruthenium, rhodium, platinum and palladium.

These metals are prized for their catalytic properties, resistance to chemical corrosion and performance in high-temperature environments, among other properties.


Thursday, January 2, 2014

Whoa: Watch Scientists Use Sound Waves to Make Things Levitate | Wired Design | Wired.com

Whoa: Watch Scientists Use Sound Waves to Make Things Levitate | Wired Design | Wired.com: ...scientists have been experimenting with acoustic levitation for decades, using sound waves to suspend materials in mid-air. What’s new here, though, is the ability to move those materials in three dimensions.

That’s made possible by the unique arrangement of the speakers themselves. Where former setups bounced sound waves off a solid plate, the Tokyo researchers instead use four panels of speakers, all facing each other. These walls combine to create an “ultrasonic focal point,” which can be moved—along with the object trapped in it—by adjusting the output from each speaker array.

Thursday, December 19, 2013

A Micro-Muscular Break Through � Berkeley Lab News Center

A Micro-Muscular Break Through � Berkeley Lab News Center: ...a micro-sized robotic torsional muscle/motor made from vanadium dioxide that for its size is a thousand times more powerful than a human muscle, able to catapult objects 50 times heavier than itself over a distance five times its length within 60 milliseconds...

Wu and his colleagues fabricated their micro-muscle on a silicon substrate from a long “V-shaped” bimorph ribbon comprised of chromium and vanadium dioxide. When the V-shaped ribbon is released from the substrate it forms a helix consisting of a dual coil that is connected at either end to chromium electrode pads. Heating the dual coil actuates it, turning it into either a micro-catapult, in which an object held in the coil is hurled when the coil is actuated, or a proximity sensor, in which the remote sensing of an object (meaning without touching it) causes a “micro-explosion,” a rapid change in the micro-muscle’s resistance and shape that pushes the object away...

The vanadium dioxide micro-muscles demonstrated reversible  torsional motion over one million cycles with no degradation. They also showed a rotational speed of up to approximately 200,000 rpm, amplitude of 500 to 2,000 degrees per millimeters in length, and an energy power density up to approximately 39 kilowatts/kilogram.

Tuesday, November 26, 2013

Fire ants writhe to make unsinkable rafts - life - 26 November 2013 - New Scientist

Fire ants writhe to make unsinkable rafts - life - 26 November 2013 - New Scientist: A raft of live fire ants, on the other hand, resists and dissipates external forces equally well on all scales. The ants can act as tiny, resistive springs by flexing and extending their legs, and they break and reform connections with their neighbours to create a flow around external forces, like being prodded with sticks. Importantly, rafts of live ants are significantly more elastic than those made of flash-frozen dead ants.

Thursday, November 14, 2013

Astronomers Discover Largest Structure in the Universe — The Physics arXiv Blog — Medium

Astronomers Discover Largest Structure in the Universe — The Physics arXiv Blog — Medium: But Horvath and co say they’ve found a significant irregularity. They say there are far more gamma ray bursts at a distance of about ten billion light years than would be expected if the distribution was uniform.

These gamma ray bursts form a structure that is some ten billion light years in size, significantly larger than even the Huge-LQG. So this thing, presumably another wall of even more distant galaxies, is the new largest structure in the universe.

Tuesday, November 5, 2013

A new topological insulator breaks symmetry, and that's a good thing

A new topological insulator breaks symmetry, and that's a good thing: Most topological insulators operate as either a p-type or n-type material on both top and bottom surfaces. But BiTeCl is asymmetric: p-type on its top surface and n-type on its bottom. This means the edges of the material could function as p-n junctions – or even many microscopic p-n junctions layered on top of each other. Even better, when the material is placed in a magnetic field, these p-n junctions develop unique edge channels that can conduct electricity with zero resistance, Chen said – and this opens all sorts of possibilities.

Moreover, this unique type of material can demonstrate many other phenomena. For instance, placing it in a static electric field can induce useful magnetic properties in the material, a phenomenon known as the topological magneto-electric effect, first predicted by theorist Shoucheng Zhang of the Stanford Institute for Materials and Energy Sciences and his group. You could even use an electric charge to induce magnetic monopoles – theorized magnets that have just one pole, north or south, rather than the usual two – and then use this exotic magnetic state to do practical work, such as storing information on a hard drive, Chen said. "This is very bizarre," he said, "because people have never found magnetic monopoles as fundamental particles."


Monday, October 28, 2013

New generation laser will herald technological breakthrough

New generation laser will herald technological breakthrough: In a paper recently published in Physical Review B, researchers from the Department of Physics demonstrate their work into bosonic lasers which emit terahertz radiation.
Such lasers have been around for years, commonly found in satellites, for environmental monitoring, astronomy, security and non-destructive testing, imaging, and medical applications. But they are considered bulky, impractical and expensive.

Sunday, October 27, 2013

New material for quantum computing discovered out of the blue

New material for quantum computing discovered out of the blue: The pigment, copper phthalocyanine (CuPc), which is similar to the light harvesting section of the chlorophyll molecule, is a low-cost organic semiconductor that is found in many household products...

...the electrons in CuPc can remain in 'superposition' ...  for surprisingly long times...

CuPc possesses many other attributes that could exploit the spin of electrons, rather than their charge, to store and process information which are highly desirable in a more conventional quantum technology. For example, the pigment strongly absorbs visible light and is easy to modify chemically and physically, so its magnetic and electrical properties can be controlled.

Friday, October 25, 2013

Neuroscientists find cortical columns in brain not uniform, challenging large-scale simulation models | KurzweilAI

Neuroscientists find cortical columns in brain not uniform, challenging large-scale simulation models | KurzweilAI: The study was based on recent advances in high-resolution imaging and reconstruction techniques (confocal microscopy and automated image-processing routines)... enabling researchers to automatically and reliably detect the 3D location and type of every nerve cell throughout the entire brain...
“By determining the exact numbers and distributions of nerve cells within almost 100 cortical columns, the substantial differences observed across columns within the same animal argue against the principle of cortical uniformity.”

Material looks cool while heating up | Science News

Material looks cool while heating up | Science News:  The compound vanadium dioxide makes such a transition around 70o Celsius, switching abruptly from being an electrical insulator to a conductor...

... the researchers heated the vanadium dioxide-sapphire sample and, with an infrared camera, measured how much infrared light the sample emitted as it warmed. The color gradually shifted from blue to red as the sample's temperature increased from 60o to 74o, as is typical for a warming object. But then something strange happened: Even though the sample’s temperature continued to rise up to 100o, the camera readout returned to an icy blue and stayed there.