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A new study from physicists at Harvard and Stanford says that wormholes can exist but they're not very useful for humans to travel through. "It takes longer to get through these wormholes than to go directly, so they are not very useful for space travel," said the author of the study, Daniel Jafferis. From the report: Despite his pessimism for pan-galactic travel, he said that finding a way to construct a wormhole through which light could travel was a boost in the quest to develop a theory of quantum gravity. The new theory was inspired when Jafferis began thinking about two black holes that were entangled on a quantum level, as formulated in the ER=EPR correspondence by Juan Maldacena from the Institute for Advanced Study and Lenny Susskind from Stanford. Although this means the direct connection between the black holes is shorter than the wormhole connection -- and therefore the wormhole travel is not a shortcut -- the theory gives new insights into quantum mechanics.

"From the outside perspective, travel through the wormhole is equivalent to quantum teleportation using entangled black holes," Jafferis said. Jafferis based his theory on a setup first devised by Einstein and Rosen in 1935, consisting of a connection between two black holes (the term wormhole was coined in 1957). Because the wormhole is traversable, Jafferis said, it was a special case in which information could be extracted from a black hole. "It gives a causal probe of regions that would otherwise have been behind a horizon, a window to the experience of an observer inside a spacetime, that is accessible from the outside," said Jafferis. The physicists presented their results at the 2019 American Physical Society April Meeting in Denver, Colorado.

A new study from physicists at Harvard and Stanford says that wormholes can exist but they're not very useful for humans to travel through. "It takes longer to get through these wormholes than to go directly, so they are not very useful for space travel," said the author of the study, Daniel Jafferis. From the report: Despite his pessimism for pan-galactic travel, he said that finding a way to construct a wormhole through which light could travel was a boost in the quest to develop a theory of quantum gravity. The new theory was inspired when Jafferis began thinking about two black holes that were entangled on a quantum level, as formulated in the ER=EPR correspondence by Juan Maldacena from the Institute for Advanced Study and Lenny Susskind from Stanford. Although this means the direct connection between the black holes is shorter than the wormhole connection -- and therefore the wormhole travel is not a shortcut -- the theory gives new insights into quantum mechanics.

"From the outside perspective, travel through the wormhole is equivalent to quantum teleportation using entangled black holes," Jafferis said. Jafferis based his theory on a setup first devised by Einstein and Rosen in 1935, consisting of a connection between two black holes (the term wormhole was coined in 1957). Because the wormhole is traversable, Jafferis said, it was a special case in which information could be extracted from a black hole. "It gives a causal probe of regions that would otherwise have been behind a horizon, a window to the experience of an observer inside a spacetime, that is accessible from the outside," said Jafferis. The physicists presented their results at the 2019 American Physical Society April Meeting in Denver, Colorado.

An anonymous reader quotes a report from CNET: One of the central puzzles in particle physics is discovering what particle (or particles!) makes up dark matter — the form of matter that is responsible for 85 percent of the mass in the known universe. Some physicists believe searching for a hypothetical particle known as an "axion" could lead to a better understanding of dark matter and to hunt for it, a team of U.S. physicists have recently designed and tested a basketball-sized, donut-shaped apparatus that can seek it out.

It has been believed that axions may be detectable by looking at an unusual type of neutron star known as a "magnetar". These small, erupting stars create some of the most powerful magnetic fields in the universe. Because of their giant magnetic power, axions would be converted to radio waves in the presence of the magnetar -- and thus, detectable by telescopes on Earth. That strange cosmic phenomenon inspired theoretical physicists to create the impressively-named ABRACADABRA experiment (the full name is "A Broadband/Resonant Approach to Cosmic Axion Detection with an Amplifying B-field Ring Apparatus" so the theorists deserve a round of applause for that backcronym). The experiment consists of a donut (or "toroid") shaped device, dangled in a freezer just above absolute zero and fine-tuned to create its own magnetic field. If axions exist, the magnetic field in the middle of the donut could reveal them. The study has been published in the journal Physical Review Letters.

An anonymous reader shares a report: Scientists in India observed the highest-voltage thunderstorm ever documented with the help of a subatomic particle you might not hear much about: the muon. The researchers operate the GRAPES-3 telescope, which measures muons, particles that are similar to electrons but heavier. Specifically, the Gamma Ray Astronomy at PeV EnergieS Phase-3 (GRAPES-3) muon telescope measures high-energy particles from outer space called cosmic rays. It typically picks up 2.5 million muons each minute, mapped on a 13-by-13 grid across the sky. But during thunderstorms, it experiences quick changes to the amount of muons it receives. The GRAPES-3 researchers added electric field monitors to the experiment, and devised a way to turn these muon fluctuations into measurements of the voltage of passing storms.

A storm on December 1, 2014, led to a relatively enormous 2 percent decrease in the amount of muons that the experiment received. According to their methods, published in Physical Review Letters, this would be equivalent to a 1.3-billion-volt electric potential in the thunderhead. This doesn't refer to a single lightning bolt, but rather the strength of the electric field caused by positively charged water molecules carried by convection to the top of the cloud while negatively charged ice remains lower down. For comparison, most lightning bolts have 100 million volts of electric potential between their ends. Subway tracks carry less than 1,000 volts.

jbmartin6 shares a report from Scientific American: In a paper published in Physical Review Letters, a group of scientists has theorized that sound waves possess mass, meaning sounds would be directly affected by gravity. They suggest phonons, particle-like collective excitations responsible for transporting sound waves across a medium, might exhibit a tiny amount of mass in a gravitational field. "You would expect classical physics results like this one to have been known for a long time by now," says Angelo Esposito from Columbia University, the lead author on the paper. "It's something we stumbled upon almost by chance."

Esposito and his colleagues built on a previous paper published last year, in which Alberto Nicolis of Columbia and Riccardo Penco from Carnegie Mellon University first suggested phonons could have mass in a superfluid. The latest study, however, shows this effect should hold true for other materials, too, including regular liquids and solids, and even air itself. And although the amount of mass carried by the phonons is expected to be tiny -- comparable with a hydrogen atom, about 10^-24 grams -- it may actually be measurable. Except, if you were to measure it, you would find something deeply counterintuitive: The mass of the phonons would be negative, meaning they would fall "up." Over time their trajectory would gradually move away from a gravitational source such as Earth. "If their gravitational mass was positive, they would fall downward," Penco says. "Because their gravitational mass is negative, phonons fall upwards." And the amount they would "fall" is equally small, varying depending on the medium the phonon is traveling through. In water, where sound moves at 1.5 kilometers per second, the negative mass of the phonon would cause it to drift at about 1 degree per second. But this corresponds to a change of 1 degree over 15 kilometers, which would be exceedingly difficult to measure.

An anonymous reader quotes a report from Scientific American: In August 2014 a rocket launched the fifth and sixth satellites of the Galileo global navigation system, the European Union's $11-billion answer to the U.S.'s GPS. But celebration turned to disappointment when it became clear that the satellites had been dropped off at the wrong cosmic "bus stops." Instead of being placed in circular orbits at stable altitudes, they were stranded in elliptical orbits useless for navigation. The mishap, however, offered a rare opportunity for a fundamental physics experiment. Two independent research teams -- one led by Pacome Delva of the Paris Observatory in France, the other by Sven Herrmann of the University of Bremen in Germany -- monitored the wayward satellites to look for holes in Einstein's general theory of relativity.

Einstein's theory predicts time will pass more slowly close to a massive object, which means that a clock on Earth's surface should tick at a more sluggish rate relative to one on a satellite in orbit. This time dilation is known as gravitational redshift. Any subtle deviation from this pattern might give physicists clues for a new theory that unifies gravity and quantum physics. Even after the Galileo satellites were nudged closer to circular orbits, they were still climbing and falling about 8,500 kilometers twice a day. Over the course of three years Delva's and Herrmann's teams watched how the resulting shifts in gravity altered the frequency of the satellites' super-accurate atomic clocks. In a previous gravitational redshift test, conducted in 1976, when the Gravity Probe-A suborbital rocket was launched into space with an atomic clock onboard, researchers observed that general relativity predicted the clock's frequency shift with an uncertainty of 1.4 x 10-4. The new studies, published last December in Physical Review Letters, again verified Einstein's prediction -- and increased that precision by a factor of 5.6. So, for now, the century-old theory still reigns.

"An experiment has confirmed that quantum mechanics allows events to occur with no definite causal order," reports an article shared by long-time Slashdot readers UpnAtom and jd. Researchers at the University of Queensland in Australia believe this could link Einstein's general theory of relativity to quantum mechanics, according to Physics World: In classical physics -- and everyday life -- there is a strict causal relationship between consecutive events. If a second event (B) happens after a first event (A), for example, then B cannot affect the outcome of A. This relationship, however, breaks down in quantum mechanics because the temporal spread of a particles's wave function can be greater than the separation in time between A and B. This means that the causal order of A and B cannot be always be distinguished by a quantum particle such as a photon.

In their experiment, Romero, Costa and colleagues created a "quantum switch", in which photons can take two paths. One path involves being subjected to operation A before operation B, while in the other path B occurs before A. The order in which the operations are performed is determined by the initial polarization of the photon as it enters the switch.... The team did the experiment using several different types of operation for A and B and in all cases they found that the measured polarization of the output photons was consistent with their being no definite causal order between when A and B was applied. Indeed, the measurements backed indefinite causal order to a whopping statistical significance of 18 -- well beyond the 5 threshold that is considered a discovery in physics.
Science Magazine applauds the experiments for "obliterating our common sense notion of before and after and, potentially, muddying the concept of causality.

hackingbear writes: Researchers at the Chinese University of Science and Technology have demonstrated stable quantum entanglement with 18 qubits, surpassing the previous world record of 10, also held by the same team. This represents a step toward realizing large-scale quantum computing, according to a recent study published in the journal Physical Review Letters. Physicist Pan Jianwei and his colleagues achieved the new record by simultaneously exploiting three different degrees of freedom-paths, polarization and orbital angular momentum of six photons, the fundamental particle of light. The outcome combination resulted in a stable 18-qubit state. Full control over the number of entangled particles determines the fundamental ability for quantum information processing, according to the study. There are early-stage quantum computers out there that argue more qubits -- such as IBM's 50-qubit machine and Google's 72-qubit Bristlecone, but in those cases, the individual quantum states of the qubits aren't (fully) controllable. "The team's next step will be to realize a 50-qubit entanglement and manipulation," according to Wang Xilin, a member of the team. The same research team also held the world record on quantum communication distance as well as operating the world's first quantum communication satellite.

Yale physicists have uncovered hints of a time crystal, a form of matter that "ticks" when exposed to an electromagnetic pulse, in a child's toy. The discovery means there are now new puzzles to solve, in terms of how time crystals form in the first place. Yale News reports: Ordinary crystals such as salt or quartz are examples of three-dimensional, ordered spatial crystals. Their atoms are arranged in a repeating system, something scientists have known for a century. Time crystals, first identified in 2016, are different. Their atoms spin periodically, first in one direction and then in another, as a pulsating force is used to flip them. That's the "ticking." In addition, the ticking in a time crystal is locked at a particular frequency, even when the pulse flips are imperfect.

Monoammonium phosphate (MAP) crystals are considered so easy to grow that they are sometimes included in crystal growing kits aimed at youngsters. It would be unusual to find a time crystal signature inside a MAP crystal, [Yale Physics professor Sean Barrett] explained, because time crystals were thought to form in crystals with more internal "disorder." The researchers used nuclear magnetic resonance (NMR) to look for a DTC signature -- and quickly found it. Another unexpected thing happened, as well. "We realized that just finding the DTC signature didn't necessarily prove that the system had a quantum memory of how it came to be," said Yale graduate student Robert Blum, a co-author on the studies. "This spurred us to try a time crystal 'echo,' which revealed the hidden coherence, or quantum order, within the system," added Rovny, also a Yale graduate student and lead author of the studies. The findings are described in a pair of studies, one in the journal Physical Review Letters and the other in the journal Physical Review B.

Yale physicists have uncovered hints of a time crystal, a form of matter that "ticks" when exposed to an electromagnetic pulse, in a child's toy. The discovery means there are now new puzzles to solve, in terms of how time crystals form in the first place. Yale News reports: Ordinary crystals such as salt or quartz are examples of three-dimensional, ordered spatial crystals. Their atoms are arranged in a repeating system, something scientists have known for a century. Time crystals, first identified in 2016, are different. Their atoms spin periodically, first in one direction and then in another, as a pulsating force is used to flip them. That's the "ticking." In addition, the ticking in a time crystal is locked at a particular frequency, even when the pulse flips are imperfect.

Monoammonium phosphate (MAP) crystals are considered so easy to grow that they are sometimes included in crystal growing kits aimed at youngsters. It would be unusual to find a time crystal signature inside a MAP crystal, [Yale Physics professor Sean Barrett] explained, because time crystals were thought to form in crystals with more internal "disorder." The researchers used nuclear magnetic resonance (NMR) to look for a DTC signature -- and quickly found it. Another unexpected thing happened, as well. "We realized that just finding the DTC signature didn't necessarily prove that the system had a quantum memory of how it came to be," said Yale graduate student Robert Blum, a co-author on the studies. "This spurred us to try a time crystal 'echo,' which revealed the hidden coherence, or quantum order, within the system," added Rovny, also a Yale graduate student and lead author of the studies. The findings are described in a pair of studies, one in the journal Physical Review Letters and the other in the journal Physical Review B.

The universe will end with a bang -- and not a whimper -- reports The New York Post, citing a new study by Harvard Researchers predicting exactly when (and how) the universe will end. But Gizmodo's science writer takes issue with the media coverage: That paper predicts that the universe's lifetime would be between 10**88 and 10**241 years, but probably probably around 10**139 years. "I think people don't have a sense as to how big these numbers are," study author and physicist Matthew Schwartz from Harvard told Gizmodo. "It's such an enormous out of time. But they think 10**139 years is 139."

The universe is around 10 billion, or 10**10 years old. 10**139 is a completely unfathomable number of years... It's more than the amount of time it would take to count every atom in the universe, if you had to wait from the Big Bang until now in between counting each atom. That number of years eludes any rational attempt to understand it (Which is probably why it sounds so close -- our heads just short circuit and say, threat!!!). It is forever.

Slashdot reader astroengine writes: One of the most expensive, complex and problematic components in gravitational wave detectors like the Laser Interferometer Gravitational-wave Observatory (LIGO) — which made the first, historic detection of these ripples in space-time in September 2015 — is the 4-kilometer-long vacuum chambers that house all the interferometer optics. But what if this requirement for ground-based gravitational wave detectors isn't required? This suggestion has been made by a pair of physicists at the University of Maryland, Baltimore County (UMBC) who are developing a method that could allow extremely sensitive interferometers to operate in the "open air."

Their work, published in the journal Physical Review Letters, uses the weird quantum properties of light to counteract interference from turbulence in the air to allow interferometer measurements to be made. Their method, which is a variation on the classic Young's double-slit experiment, has been demonstrated in a tabletop experiment — but gravitational wave scientists are skeptical that it could be scaled up to remove sophisticated vacuums from their detectors.

dmoberhaus writes: An international team of mathematicians has found that there are theoretical black holes that would allow an observer to survive passage through the event horizon. This would result in the breakdown of determinism, a fundamental feature of the universe that allows physics to have predictive power, and result in the destruction of the observer's past and present them with an infinite number of futures. The findings were detailed in a report published last week in Physical Review Letters.

sciencehabit writes from a report via Science Magazine: You can't weigh the universe's smallest particles on a bathroom scale. But in a clever new experiment, physicists have found one such particle -- the proton -- is lighter than previously thought. The researchers found the mass to be 1.007276466583 atomic mass units. That's roughly 30 billionths of a percent lower than the average value from past experiments -- a seemingly tiny difference that is actually significant by three standard deviations. The result both creates and clears up mysteries, and could help explain the universe as we know it. The findings have been published in the journal Physical Review Letters.

sycodon quotes a report from The New York Times (Warning: may be paywalled; alternate source): Astronomers said Thursday that they had felt space-time vibrations known as gravitational waves from the merger of a pair of mammoth black holes resulting in a pit of infinitely deep darkness weighing as much as 49 suns, some 3 billion light-years from here. This is the third black-hole smashup that astronomers have detected since they started keeping watch on the cosmos back in September 2015, with LIGO, the Laser Interferometer Gravitational-Wave Observatory. All of them are more massive than the black holes that astronomers had previously identified as the remnants of dead stars. The latest detection was made at 10:11 GMT on January 4, and is described in a paper accepted for publication in the journal Physical Review Letters. "The analysis suggests the two black holes that coalesced had starting masses that were just over 31 times and 19 times that of our Sun," reports BBC. "And when they finally came together, they produced a single object of a little under 49 solar masses. It means the unison radiated a simply colossal quantity of pure energy."

The discovery of "non-equilibrium matter" could re-write the rules of physics. Long-time Slashdot reader jasonbrown quotes ScienceAlert: For months now, there's been speculation that researchers might have finally created time crystals — strange crystals that have an atomic structure that repeats not just in space, but in time, putting them in perpetual motion without energy. Now it's official — researchers have just reported in detail how to make and measure these bizarre crystals. And two independent teams of scientists claim they've actually created time crystals in the lab based off this blueprint, confirming the existence of an entirely new form of matter.
Both teams -- one at Harvard and the other at the University of Maryland -- have submitted their findings to peer-reviewed publications, according to the article, and "the fact that two separate teams have used the same blueprint to make time crystals out of vastly different systems is promising."

mspohr writes: The Guardian has a news article about a recently published journal entry proposing a way to test the theory that the speed of light was infinite at the birth of the universe: "The newborn universe may have glowed with light beams moving much faster than they do today, according to a theory that overturns Einstein's century-old claim that the speed of light is a constant. Joao Magueijo, of Imperial College London, and Niayesh Afshordi, of the University of Waterloo in Canada, propose that light tore along at infinite speed at the birth of the universe when the temperature of the cosmos was a staggering ten thousand trillion trillion celsius. Magueijo and Afshordi came up with their theory to explain why the cosmos looks much the same over vast distances. To be so uniform, light rays must have reached every corner of the cosmos, otherwise some regions would be cooler and more dense than others. But even moving at 1bn km/h, light was not traveling fast enough to spread so far and even out the universe's temperature differences." Cosmologists including Stephen Hawking have proposed a theory called inflation to overcome this conundrum. Inflation theorizes that the temperature of the cosmos evened out before it exploded to an enormous size. The report adds: "Magueijo and Afshordi's theory does away with inflation and replaces it with a variable speed of light. According to their calculations, the heat of universe in its first moments was so intense that light and other particles moved at infinite speed. Under these conditions, light reached the most distant pockets of the universe and made it look as uniform as we see it today. Scientists could soon find out whether light really did outpace gravity in the early universe. The theory predicts a clear pattern in the density variations of the early universe, a feature measured by what is called the 'spectral index.' Writing in the journal Physical Review, the scientists predict a very precise spectral index of 0.96478, which is close to the latest, though somewhat rough, measurement of 0.968."

An anonymous reader writes from a report via ScienceAlert: Physicists have confirmed the existence of pear-shaped nuclei, which challenges the fundamental theories of physics that explain our Universe. "We've found these nuclei literally point towards a direction in space. This relates to a direction in time, providing there's a well-defined direction in time and we will always travel from past to present," Marcus Scheck from the University of the West of Scotland told Kenneth MacDonald at BBC News. Until recently, it was generally accepted that nuclei of atoms could only be one of three shapes: spherical, discus, or rugby ball. The first discovery of a pear-shaped nucleus was back in 2013, when physicists at CERN discovered isotope Radium-224. Now, that find has been confirmed by a second study, which shows that the nucleus of the isotope Barium-144 is also asymmetrical and pear-shaped. In regard to time travel, Scheck says that this uneven distribution of mass and charge caused Barium-144's nucleus to "point" in a certain direction in spacetime, and this bias could explain why time seems to only want to go from past to present, and not backwards, even if the laws of physics don't care which way it goes.

An anonymous reader quotes a report from The Guardian: Physicists have detected ripples in the fabric of spacetime that were set in motion by the collision of two black holes far across the universe more than a billion years ago. The event marks only the second time that scientists have spotted gravitational waves, the tenuous stretching and squeezing of spacetime predicted by Einstein more than a century ago. The faint signal received by the twin instruments of the Laser Interferometer Gravitational Wave Observatory (LIGO) in the US revealed two black holes circling one another 27 times before finally smashing together at half the speed of light. The cataclysmic event saw the black holes, one eight times more massive than the sun, the other 14 times more massive, merge into one about 21 times heavier than the sun. In the process, energy equivalent to the mass of the sun radiated into space as gravitational waves. Writing in the journal Physical Review Letters on Wednesday, the LIGO team describes how a second rush of gravitational waves showed up in their instrument a few months after the first, at 3.38am UK time on Boxing Day morning 2015. An automatic search detected the signals and emailed the LIGO scientists within minutes to alert them. The latest signals arrived at the Livingston detector 1.1milliseconds before they hit the Hanford detector, allowing scientists on the team to roughly work out the position of the collision in the sky. In February, LIGO scientists officially announced the first-ever observation of gravity waves.

MikeChino quotes a report from Inhabitat: Scientists just discovered a new state of water molecules that displays some pretty unexpected characteristics. This discovery, made by researchers at the U.S. Department of Energy's Oak Ridge National Laboratory (ORNL), reveals that water molecules "tunnel" in ultra-small hexagonal channels (measuring only 5 angstrom across) of the mineral beryl. Basically, this means the molecules spread out when they are trapped in confined spaces, taking a new shape entirely. The ORNL used neutron scattering and computational modeling to reveal the "tunneling" state of water that breaks the rules of known fundamentals seen in gas, liquid, or solid state. The researchers said the discovery describes the behavior of water molecules present in tightly confined areas such as cell walls, soils, and rocks. The study was published in Physical Review Letters on April 22.

An anonymous reader writes: One of the oddest predictions of quantum theory – that a system can't change while you're watching it – has been confirmed in an experiment by Cornell physicists. Graduate students Yogesh Patil and Srivatsan Chakram created and cooled a gas of about a billion Rubidium atoms inside a vacuum chamber and suspended the mass between laser beams (abstract).

In that state the atoms arrange in an orderly lattice just as they would in a crystalline solid. But at such low temperatures the atoms can "tunnel" from place to place in the lattice. The famous Heisenberg uncertainty principle says that position and velocity of a particle are related and cannot be simultaneously measured precisely.

The researchers observed the atoms under a microscope by illuminating them with a separate imaging laser. A light microscope can't see individual atoms, but the imaging laser causes them to fluoresce, and the microscope captured the flashes of light. When the imaging laser was off, or turned on only dimly, the atoms tunneled freely. But as the imaging beam was made brighter and measurements made more frequently, the tunneling reduced dramatically.

JoshuaZ writes: Researchers from Brown University have tentatively identified an alloy of hafnium, nitrogen and carbon as having an expected melting point of about 7,460 degrees Fahrenheit (4120 Celsius). This exceeds that of the previous record-breaker, tantalum hafnium carbide, which melts at 7,128 F (3942 C). Its record stood for almost a century. At this point, the new alloy is still hypothetical, based on simulations, so the new record has not yet been confirmed by experiment. The study was published in Physical Review B (abstract), and a lay-summary is available at the Washington Post. If the simulations turn out to be correct, the new alloy may be useful in parts like jet engines, and the door will be opened to using similar simulations to search for substances with even higher melting points or with other exotic properties.

jan_jes writes: Physicists at MIT have successfully cooled molecules in a gas of sodium potassium (NaK) to a temperature of 500 nanokelvins. The researchers found that the ultracold molecules were relatively long-lived and stable, resisting reactive collisions with other molecules (abstract). The molecules also exhibited very strong dipole moments — strong imbalances in electric charge within molecules that mediate magnet-like forces between molecules over large distances. According to professor Martin Zwierlein, "We are very close to the temperature at which quantum mechanics plays a big role in the motion of molecules. So these molecules would no longer run around like billiard balls, but move as quantum mechanical matter waves. And with ultracold molecules, you can get a huge variety of different states of matter, like superfluid crystals, which are crystalline, yet feel no friction, which is totally bizarre. This has not been observed so far, but predicted. We might not be far from seeing these effects, so we’re all excited."

New submitter citpyrc sends this news from the Vienna University of Technology: The "holographic principle" asserts that a mathematical description of the universe actually requires one fewer dimension than it seems. What we perceive as three dimensional may just be the image of two dimensional processes on a huge cosmic horizon. Up until now, this principle has only been studied in exotic spaces with negative curvature. This is interesting from a theoretical point of view, but such spaces are quite different from the space in our own universe. Results obtained by scientists at Vienna (abstract) now suggest that the holographic principle even holds in a flat spacetime, like ours.

An anonymous reader writes: Scientists at MIT have created a small, tabletop particle detector capable of identifying individual electrons within a cloud of radioactive gas. "As the radioactive krypton gas decays, it emits electrons that vibrate at a baseline frequency before petering out; this frequency spikes again whenever an electron hits an atom of radioactive gas. As an electron ping-pongs against multiple atoms in the detector, its energy appears to jump in a step-like pattern." The researchers used the detector to record the activity of 100,000 different electrons within the gas (abstract). They're hoping that with enough data about how the electrons bounce around, they'll be able to pinpoint the amount of energy released during these krypton atom decay events. Once they know how much energy is released, they can figure out the mass of a neutrino, which is also emitted during the decay.

wjcofkc sends this report from R&D Magazine: If we are ever to fully harness the power of light for use in optical devices, it is necessary to understand photons — the fundamental unit of light. Achieving such understanding, however, is easier said than done. That's because the physical behavior of photons — similar to electrons and other sub-atomic particles — is characterized not by classical physics, but by quantum mechanics.

Now, in a study published in Physical Review Letters (abstract), scientists from Bar-Ilan University have observed the point at which classical and quantum behavior converge. Using a fiber-based nonlinear process, the researchers were able to observe how, and under what conditions, 'classical' physical behavior emerges from the quantum world.

HughPickens.com writes Eric Mack reports at Cnet that a team of researchers at Cornell University, inspired by the book "World War Z" by Max Brooks, have used statistical-mechanics to model how an actual zombie outbreak might unfold and determined the best long-term strategy for surviving the walking dead: Head for the hills. Specifically, you should probably get familiar now with the general location of Glacier National Park so that when it all goes down, you can start heading in that direction. The project started with differential equations to model a fully connected population, then moved on to lattice-based models, and ended with a full US-scale simulation of an outbreak across the continental US. "At their heart, the simulations are akin to modeling chemical reactions taking place between different elements and, in this case, we have four states a person can be in--human," says Alex Alemi, "infected, zombie, or dead zombie--with approximately 300 million people."

Alemi believes cities would succumb to the zombie scourge quickly, but the infection rate would slow down significantly in more sparsely populated areas and could take months to reach places like the Northern Rockies and Glacier National Park. "Given the dynamics of the disease, once the zombies invade more sparsely populated areas, the whole outbreak slows down--there are fewer humans to bite, so you start creating zombies at a slower rate," Alemi says. Once you hit Montana and Idaho, you might as well keep heading farther north into the Canadian Rockies and all the way up to Alaska where data analysis shows you're most likely to survive the zombie apocalypse. The state with the lowest survival rate? — New Jersey. Unfortunately a full scale simulation of an outbreak in the United States shows that for `realistic' parameters, we are largely doomed.

concertina226 writes: A team of physicists at University of California, Riverside have discovered how to induce magnetism in graphene in a way that still preserves the material's electronic properties, which paves the way for graphene to be used as a semiconductor.

The researchers grew a sheet of yttrium iron garnet using laser molecular beam epitaxy in a laboratory (abstract). Magnetic substances like iron are known to disrupt graphene's electrical conduction properties, but yttrium iron garnet works well as it is an electric insulator.

When a graphene sheet was placed on top of an atomically smooth sheet of yttrium iron garnet, the graphene borrowed the magnetic properties from the yttrium iron garnet and became magnetized without the need for doping.

An anonymous reader writes: A new study confirms the potential hazard of nearby gamma-ray bursts. It quantifies the probability of an event near Earth, and more generally in the Milky Way and other galaxies over time: "[Evolved] life as it exists on Earth could not take place in almost any galaxy that formed earlier than about five billion years after the Big Bang." This could explain the Fermi's paradox, or why we don't see billion-year-old civilizations all around us.

BarbaraHudson writes: In a new series of experiments, scientists report (abstract) that neutrinos, notable for how infrequently they interact with matter, can strike a glancing blow on an atom's nucleus, and the side effect is the generation of a new particle out of a vacuum. Professor Kevin McFarland says the creation of the new particle is what shields the nucleus from being blown apart by the collision. "Producing an entirely new particle – in this case a charged pion – requires much more energy than it would take to blast the nucleus apart – which is why the physicists are always surprised that the reaction happens as often as it does. McFarland adds that even painstakingly detailed theoretical calculations for this reaction 'have been all over the map.'"

TaleSlinger sends word of a newly-discovered "mathematical relationship — between material thickness, temperature, and electrical resistance — that appears to hold in all superconductors." The work (abstract), led by Yachin Irvy, comes out of MIT's Research Laboratory of Electronics. Researchers found that a particular superconductor (niobium nitride) didn't fit earlier models estimating the temperature at which it changes from normal conductivity to superconductivity. So the researchers conducted a series of experiments in which they held constant either thickness or “sheet resistance,” the material’s resistance per unit area, while varying the other parameter; they then measured the ensuing changes in critical temperature. A clear pattern emerged: Thickness times critical temperature equaled a constant — call it A — divided by sheet resistance raised to a particular power — call it B. ... The other niobium nitride papers Ivry consulted bore out his predictions, so he began to expand to other superconductors. Each new material he investigated required him to adjust the formula’s constants — A and B. But the general form of the equation held across results reported for roughly three dozen different superconductors.

Z00L00K sends this report from New Scientist: Networks shaped like delicate snowflakes are the ones that are easiest to fix when disaster strikes. Power grids, the internet and other networks often mitigate the effects of damage using redundancy: they build in multiple routes between nodes so that if one path is knocked out by falling trees, flooding or some other disaster, another route can take over. But that approach can make them expensive to set up and maintain. The alternative is to repair networks with new links as needed, which brings the price down – although it can also mean the network is down while it happens.

As a result, engineers tend to favor redundancy for critical infrastructure like power networks, says Robert Farr of the London Institute for Mathematical Sciences. So Farr and colleagues decided to investigate which network structures are the easiest to repair. They simulated a variety of networks, linking nodes in a regular square or triangular pattern and looked at the average cost of repairing different breaks, assuming that expense increases with the length of a rebuilt link. ... They found the best networks are made from partial loops around the units of the grid, with exactly one side of each loop missing (abstract). All of these partial loops link together, back to a central source. ... These networks have three levels of hierarchy – major arms sprouting from a central hub that branch and then branch again, but no further. When drawn, they look remarkably like snowflakes, which have a similar branching structure.

An anonymous reader writes A few months ago researchers announced they had discovered proof of the big bang. Now they're not so sure. Further research suggests cosmic dust might have skewed the results. "Back in March, the BICEP2 team reported a twisted pattern in the sky, which they attributed to primordial gravitational waves, wrinkles in the fabric of the universe that could have been produced when the baby universe went through an enormous growth spurt. If correct, this would confirm the theory of inflation, which says that the universe expanded exponentially in the first slivers of a second after the big bang – many believe that it continues to expand into an ever-growing multiverse. Doubts about the announcement soon emerged. The BICEP2 team identified the waves based on how they twisted, or polarised, the photons in the cosmic microwave background (CMB), the earliest light emitted in the universe around 380,000 years after the big bang. Other objects, such as the ashes of exploding stars or dust within our galaxy, can polarise light as well."

An anonymous reader writes "In 1970, Russian physicist Vitaly Efimov developed mathematical proof (PDF) that any three-particle substance, referred to as a trimer, will scale up or down in size by a factor of 22.7 and that if the particles are not all of the same type, 'the scaling factor of 22.7 decreases according to the particles' relative masses.' In 2006, physicists in Austria proved that Efimov's trimers can be created in laser-cooled environments. And now, in 2014, physicists in Austria, Germany, and the U.S. have physical proof that Efimov's trimers do indeed scale by a factor of 22.7 if they are comprised of the same particles or a lower ratio relative to their particles' masses if they are comprised of a mixture of different particles (abstract 1, abstract 2, abstract 3). 22.7 — a.k.a., the rule of three — now appears to be as significant as pi."

rjmarvin (3001897) writes "Researchers at the U.K.'s Lancaster University have reimagined the fundamental logic behind encryption, stumbling across a radically new way to encrypt data while creating software models to simulate how the human heart and lungs coordinate rhythms. The encryption method published in the American Physical Society journal and filed as a patent entitled 'Encoding Data Using Dynamic System Coupling,' transmits and receive multiple encrypted signals simultaneously, creating an unlimited number of possibilities for the shared encryption key and making it virtually impossible to decrypt using traditional methods. One of the researchers, Peter McClintock, called the encryption scheme 'nearly unbreakable.'

Daniel_Stuckey writes "The United States is currently gripped in a bout of earthquake mania, following a series of significant tremors in the West. And any time Yellowstone, LA, or San Francisco shakes, people start to wonder if it's a sign of The Big One to come. Yet even after decades of research, earthquake prediction remains notoriously hard, and not every building in quake-prone areas has an earthquake-resistant design. What if, instead of quaking in our boots, we could stop quakes in their tracks? Theoretically, it's not a crazy idea. Earthquakes propagate in waves, and if noise-canceling headphones have taught us anything, it's that waves can be absorbed, reflected, or canceled out. Today, a paper published in Physical Review Letters suggests how that might be done. It's the result of French research into the use of metamaterials—broadly, materials with properties not found in nature—to modify seismic waves, like a seismic cloaking device."

b30w0lf writes "Gravitational wave detection — i.e. the detection of propagating ripples in spacetime — is a hot subject these days, with ground-based interferometer experiments like LIGO active, and hopes for a space interferometer like LISA. However, physicist Freeman Dyson proposed back in 1969 that the earth itself could be used as a gravitational wave detector. The idea is behind the approach is that gravitational waves impact the earth's crust, causing potentially detectable seismic waves. Using Dyson's approach, Physicists at Harvard and NINP, Florence were able to put an upper limit on the intensity of gravitational background radiation based on a year of observational seismic data (abstract, full pre-print). The upper limit they found improved currently laboratory upper limits by 9 orders of magnitude."

b30w0lf writes "Gravitational wave detection — i.e. the detection of propagating ripples in spacetime — is a hot subject these days, with ground-based interferometer experiments like LIGO active, and hopes for a space interferometer like LISA. However, physicist Freeman Dyson proposed back in 1969 that the earth itself could be used as a gravitational wave detector. The idea is behind the approach is that gravitational waves impact the earth's crust, causing potentially detectable seismic waves. Using Dyson's approach, Physicists at Harvard and NINP, Florence were able to put an upper limit on the intensity of gravitational background radiation based on a year of observational seismic data (abstract, full pre-print). The upper limit they found improved currently laboratory upper limits by 9 orders of magnitude."

sciencehabit writes "As it approaches its fifth birthday, the National Ignition Facility (NIF), a troubled laser fusion facility in California, has finally produced some results that fusion scientists can get enthusiastic about. In a series of experiments late last year (abstract 1, abstract 2), NIF researchers managed to produce energy yields 10 times greater than produced before and to demonstrate the phenomenon of self-heating that will be crucial if fusion is to reach its ultimate goal of 'ignition'—a self-sustaining burning reaction that produces more energy than it consumes."

symbolset writes "Ball lightning has been reported for hundreds of years, and experimentally produced, but for the first time a natural will 'o wisp has been captured on video and amazingly, spectrograph, accidentally by researchers studying ordinary lightning."

symbolset writes "Ball lightning has been reported for hundreds of years, and experimentally produced, but for the first time a natural will 'o wisp has been captured on video and amazingly, spectrograph, accidentally by researchers studying ordinary lightning."

theodp writes "In 'The Online Education Revolution Drifts Off Course,' NPR's Eric Westervelt reports that 2013 might be dubbed the year that online education fell back to earth. Westervelt joins others in citing the higher failure rate of online students as evidence that MOOCs aren't all they're cracked up to be. But viewed another way, the ability to try and fail without dire debt or academic consequences that's afforded by MOOCs could be viewed as a feature and not a bug. Being able to learn at one's own pace is what Dr. Yung Tae Kim has long argued is something STEM education sorely lacks, and MOOCs make it feasible to allow students to try-try-again if at first they don't succeed. By the way, if you couldn't scrape together $65,000 to take CS50 in-person at Harvard this year, today's the first day of look-Ma-no-tuition CS50x (review), kids!"

sciencehabit writes "Theoretical physicists have forged a connection between the concept of entanglement — itself a mysterious quantum mechanical connection between two widely separated particles — and that of a wormhole — a hypothetical connection between black holes that serves as a shortcut through space (first abstract, second abstract). The insight could help physicists reconcile quantum mechanics and Einstein's general theory of relativity, perhaps the grandest goal in theoretical physics."

sciencehabit writes "Theoretical physicists have forged a connection between the concept of entanglement — itself a mysterious quantum mechanical connection between two widely separated particles — and that of a wormhole — a hypothetical connection between black holes that serves as a shortcut through space (first abstract, second abstract). The insight could help physicists reconcile quantum mechanics and Einstein's general theory of relativity, perhaps the grandest goal in theoretical physics."

At Kurzweil AI, an article proclaims that the next wonder material for computer chips may be an unexpectedly common one: "Move over, graphene. 'Stanene' — a single layer of tin atoms — could be the world’s first material to conduct electricity with 100 percent efficiency at the temperatures that computer chips operate, according to a team of theoretical physicists led by researchers from the U.S. Department of Energy’s (DOE) SLAC National Accelerator Laboratory and Stanford University." (Original paper is available here, but paywalled.)

New submitter ElSergio writes "In a two-part interview with the American Physical Society, Elon Musk, founder of PayPal, Tesla Motors and SpaceX, talks about how important it is to be able to think in terms of first principles, a tool learned as a physics student. Later in the interview, he recommends against obtaining an MBA, claiming, 'It teaches people all sorts of wrong things' and 'They don't teach people to think in MBA schools.' In fact. if you are in business and want to work for SpaceX, you will have a better chance getting hired if you do not have one. According to Musk, 'I hire people in spite of an MBA'. He goes on to point out that if you look at the senior managers in his companies, you will not find very many MBAs there."

New submitter ElSergio writes "In a two-part interview with the American Physical Society, Elon Musk, founder of PayPal, Tesla Motors and SpaceX, talks about how important it is to be able to think in terms of first principles, a tool learned as a physics student. Later in the interview, he recommends against obtaining an MBA, claiming, 'It teaches people all sorts of wrong things' and 'They don't teach people to think in MBA schools.' In fact. if you are in business and want to work for SpaceX, you will have a better chance getting hired if you do not have one. According to Musk, 'I hire people in spite of an MBA'. He goes on to point out that if you look at the senior managers in his companies, you will not find very many MBAs there."

Nerval's Lobster writes "University of Toronto researchers have demonstrated an invisibility cloak that hides objects within an electromagnetic field, rather than swaddling it in meta-materials as other approaches require. Instead of covering an object completely in an opaque cloak that then mimics the appearance of empty air, the technique developed by university engineering Prof. George Eleftheriades and Ph.D. candidate Michael Selvanayagam makes objects invisible using the ability of electromagnetic fields to redirect or scatter waves of energy. The approach is similar to that of 'stealth' aircraft whose skin is made of material that absorbs the energy from radar systems and deflects the rest away from the radar detectors that sent them. Rather than scattering radio waves passively due to the shape of its exterior, however, the Toronto pair's 'cloak' deflects energy using an electromagnetic field projected by antennas that surround the object being hidden. Most of the proposals in a long list of 'invisibility cloaks' announced during the past few years actually conceal objects by covering them with an opaque blanket, which becomes 'invisible' by displaying an image of what the space it occupies would look like if neither the cloak nor the object it concealed were present. An invisibility cloak concealing an adolescent wizard hiding in a corner, for example, would display an image of the walls behind it in an effort to fool observers into thinking there was no young wizard present to block their view of the empty corner. 'We've taken an electrical engineering approach, but that's what we are excited about,' Eleftheriades said in a public announcement of the paper's publication. (The full text is available as a free PDF here.)"

First time accepted submitter ydrozd writes "Until recently, most physicists believed that an observer falling into a black hole would experience nothing unusual when crossing its event horizon. As has been previously mentioned on Slashdot, there is a strong argument, initially based on observing an entangled pair at the event horizon, that suggests that the unfortunate observer would instead be burned up by a high energy quanta (a.k.a "firewall") just before crossing the black hole's event horizon. A new paper significantly improves the argument by removing reliance on quantum entanglement. The existence of black hole "firewalls" is a rare breakthrough in theoretical physics."

benonemusic writes "The commercially available D-Wave computer has demonstrated its ability to perform increasingly complex tasks. But is it a real quantum computer? A new round of research continues the debate over how much its calculations owe to exotic quantum-physics phenomena. 'One side argues there is too much noise in the D-Wave system, which prevents consistent entanglement. But in an adiabatic device, certain types of entanglement are not as vital as they are in the traditional model of a quantum computer. Some researchers are attempting to solve this conundrum by proving the presence or absence of entanglement. If they show entanglement is absent, that would be the end of the discussion. On the other hand, even if some of D-Wave's qubits are entangled, this doesn't mean the device is taking advantage of it. Another way to prove D-Wave's quantumness would be to confirm it is indeed performing quantum, and not classical, annealing. Lidar has published work to this effect, but that triggered opposition, and then a counter-point. The debate continues.'"