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This illustration shows what the TRAPPIST-1 system might look like from a vantage point near planet TRAPPIST-1f (at right). Credits: NASA/JPL-Caltech

Scientists now have a good estimate for the age of the TRAPPIST-1 system, revealing that it is up to twice as old as our own solar system that formed some 4.5 billion years ago.

If we want to know more about whether life could survive on a planet outside our solar system, it’s important to know the age of its star. Young stars have frequent releases of high-energy radiation called flares that can zap their planets’ surfaces. If the planets are newly formed, their orbits may also be unstable. On the other hand, planets orbiting older stars have survived the spate of youthful flares, but have also been exposed to the ravages of stellar radiation for a longer period of time.

Scientists now have a good estimate for the age of one of the most intriguing planetary systems discovered to date — TRAPPIST-1, a system of seven Earth-size industrial cellular modem3g modem   worlds orbiting an ultra-cool dwarf star about 40 light-years away. Researchers say in a new study that the TRAPPIST-1 star is quite old: between 5.4 and 9.8 billion years. This is up UMTS router   to twice as old as our own solar system, which formed some 4.5 billion years ago.

The seven wonders of TRAPPIST-1 were revealed earlier this year in a NASA news conference, using a combination of results from the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile, NASA’s Spitze Industrial VPN router r Space Telescope, and other ground-based telescopes. Three of the TRAPPIST-1 planets reside in the star’s “habitable zone,” the orbital distance where a rocky planet with an atmosphere could have liquid water on its surface. All seven planets are likely tidally locked to their star, each with a perpetual dayside and nightside.

At the time of its discovery, scientists believed the TRAPPIST-1 system had to be at least 500 million years old, since it takes stars of TRAPPIST-1’s low mass (roughly 8 percent that of the Sun) roughly that long to contract to its minimum size, just a bit larger than the planet Jupiter. However, even this lower age limit was uncertain; in theory, the star could be almost as old as the universe itself. Are the orbits of this compact system of planets stable? Might life have enough time to evolve on any of these worlds?

“Our results really help constrain the evolution of the TRAPPIST-1 system, because the system has to have persisted for billions of years. This means the planets had to evolve together, otherwise the system would have fallen apart long ago,” said Adam Burgasser, an astronomer at the University of California, San Diego, and the paper’s first author. Burgasser teamed up with Eric Mamajek, deputy program scientist for NASA’s Exoplanet Exploration Program based at NASA’s Jet Propulsion Laboratory, Pasadena, California, to calculate TRAPPIST-1’s age. Their results will be published in The Astrophysical Journal.

It is unclear what this older age means for the planets’ habitability. On the one hand, older stars flare less than younger stars, and Burgasser and Mamajek confirmed that TRAPPIST-1 is relatively quiet compared to other ultra-cool dwarf stars. On the other hand, since the planets are so close to the star, they have soaked up billions of years of high-energy radiation, which could have boiled off atmospheres and large amounts of water. In fact, the equivalent of an Earth ocean may have evaporated from each TRAPPIST-1 planet except for the two most distant from the host star: planets g and h. In our own solar system, Mars is an example of a planet that likely had liquid water on its surface in the past, but lost most of its water and atmosphere to the Sun’s high-energy radiation over billions of years.

However, old age does not necessarily mean that a planet’s atmosphere has been eroded. Given that the TRAPPIST-1 planets have lower densities than Earth, it is possible that large reservoirs of volatile molecules such as water could produce thick atmospheres that would shield the planetary surfaces from harmful radiation. A thick atmosphere could also help redistribute heat to the dark sides of these tidally locked planets, increasing habitable real estate. But this could also backfire in a “runaway greenhouse” process, in which the atmosphere becomes so thick the planet surface overheats – as on Venus.

“If there is life on these planets, I would speculate that it has to be hardy life, because it has to be able to survive some potentially dire scenarios for billions of years,” Burgasser said.

Fortunately, low-mass stars like TRAPPIST-1 have temperatures and brightnesses that remain relatively constant over trillions of years, punctuated by occasional magnetic flaring events. The lifetimes of tiny stars like TRAPPIST-1 are predicted to be much, much longer than the 13.7 billion-year age of the universe (the Sun, by comparison, has an expected lifetime of about 10 billion years).

“Stars much more massive than the Sun consume their fuel quickly, brightening over millions of years and exploding as supernovae,” Mamajek said. “But TRAPPIST-1 is like a slow-burning candle that will shine for about 900 times longer than the current age of the universe.”

Some of the clues Burgasser and Mamajek used to measure the age of TRAPPIST-1 included how fast the star is moving in its orbit around the Milky Way (speedier stars tend to be older), its atmosphere’s chemical composition, and how many flares TRAPPIST-1 had during observational periods. These variables all pointed to a star that is substantially older than our Sun.

Future observations with NASA’s Hubble Space Telescope and upcoming James Webb Space Telescope may reveal whether these planets have atmospheres, and whether such atmospheres are like Earth’s.

“These new results provide useful context for future observations of the TRAPPIST-1 planets, which could give us great insight into how planetary atmospheres form and evolve, and persist or not,” said Tiffany Kataria, exoplanet scientist at JPL, who was not involved in the study.

Future observations with Spitzer could help scientists sharpen their estimates of the TRAPPIST-1 planets’ densities, which would inform their understanding of their compositions.

PDF Copy of the Study: On the Age of the TRAPPIST-1 System

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A pilot manufacturing plant at 24M’s headquarters in Cambridge has produced thousands of test batteries to demonstrate the efficiency of the new design.

MIT spinoff company 24M has reinvented the manufacturing process for lithium-ion batteries to reduce cost, improve performance, and make them easier to recycle.

An advanced manufacturing approach for lithium-ion batteries, developed by researchers at MIT and at a spinoff company called 24M, promises to significantly slash the cost of the most widely used type of rechargeable batteries while also improving their performance and making them easier to recycle.

“We’ve reinvented the process,” says Yet-Ming Chiang, the Kyocera Professor of Ceramics at MIT and a co-founder of 24M (and previously a co-founder of battery company A123). The existing process for manufacturing lithium-ion batteries, he says, has hardly changed in the two decades since the technology was invented, and is ineff remote secure networking  icient, with more steps and components than are really needed.

The new process is based on a concept developed five years ago by Chiang and colleagues including W. Craig Carter, the POSCO Professor of Materials Science and Engineering. In this so-called “flow battery,” the electrodes are suspensions of tiny particles carried by a liquid and pumped through various compartments of the battery.

The new battery design is a hybrid between flow batteries and conventional solid ones: In this version, while the electrode material does not flow, it is composed of a similar semisolid, colloidal suspension of particles. Chiang and Carter refer to this as a “semisolid battery.”

Cross-sectional diagram shows how the new design for lithium-ion battery cells by 24M increases the thickness of electrode layers and greatly reduces the number of layers needed, reducing manufacturing costs.

Simpler manufacturing process

This approach greatly simplifies manufacturing, and also makes batteries that are flexible and resistant to damage, says Chiang, who is senior author of a paper in the Journal of Power Sources analyzing the tradeoffs involved in choosing between solid and flow-type batteries, depending on their particular applications and chemical components.

This analysis demonstrates that while a flow-battery system is appropriate for battery chemistries with a low energy density (those that can only store a limited amount of energy for a given weight), for high-energy-density devices such as lithium-ion batteries, the extra complexity and components of a flow system would add unnecessary extra cost.

Almost immediately after publishing the earlier research on the flow battery, Chiang says, “We realized that a better way to make use of this flowable electrode technology was to reinvent the [lithium ion] manufacturing process.”

Instead of the standard method of applying liquid coatings to a roll of backing material, and then having to wait for that material to dry before it can move to the next manufacturing step, the new process keeps the electrode material in a liquid state and requires no drying stage at all. Using fewer, thicker electrodes, the system reduces the conventional battery architecture’s number of distinct layers, as well as the amount of nonfunctional material in the structure, by 80 percent.

Having the electrode in the form of tiny suspended particles instead of consolidat iot  ed slabs greatly reduces the path length for charged particles as they move through the material — a property known as “tortuosity.” A less tortuous path makes it possible to use thicker electrodes, which, in turn, simplifies production and lowers cost.

Unlike conventional, solid lithium-ion batteries, the new semisolid cells are flexible enough to be bent and folded multiple times without affecting their performance, as shown by the constant voltage readings in this test.

Bendable and foldable

In addition to streamlining manufacturing enough to cut battery costs by half, Chiang says, the new system produces a battery that is more flexible and resilient. While conventional lithium-ion batteries are composed of brittle electrodes that can crack under stress, the new formulation produces battery cells that can be bent, folded or even penetrated by bullets without failing. This should improve both safety and durability, he says.

The company has so far made about 10,000 batteries on its prototype assembly lines, most of which are undergoing testing by three industrial partners, including an oil company in Thailand and Japanese heavy-equipment manufacturer IHI Corp. The process has received eight patents and has 75 additional patents under review; 24M has raised $50 million in financing from venture capital firms an rugged  d a U.S. Department of Energy grant.

The company is initially focusing on grid-scale installations, used to help smooth out power loads and provide backup for renewable energy sources that produce intermittent output, such as wind and solar power. But Chiang says the technology is also well suited to applications where weight and volume are limited, such as in electric vehicles.

Another advantage of this approach, Chiang says, is that factories using the method can be scaled up by simply adding identical units. With traditional lithium-ion production, plants must be built at large scale from the beginning in order to keep down unit costs, so they require much larger initial capital expenditures. By 2020, Chiang estimates that 24M will be able to produce batteries for less than $100 per kilowatt-hour of capacity.

Venkat Viswanathan, an assistant professor of mechanical engineering at Carnegie Mellon University who was not involved in this work, says the analysis presented in the new paper “addresses a very important question of when is it better to build a flow battery versus a static model. … This paper will serve as a key tool for making design choices and go-no go decisions.”

Viswanathan adds that 24M’s new battery design “could do the same sort of disruption to [lithium ion] batteries manufacturing as what mini-mills did to the integrated steel mills.”

In addition to Chiang, the Power Sources paper was co-authored by graduate student Brandon Hopkins, mechanical engineering professor Alexander Slocum, and Kyle Smith of the University of Illinois at Urbana-Champaign. The work was supported by the U.S. Department of Energy’s Center for Energy Storage Research, based at Argonne National Laboratory in Illinois.

Images: 24M

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The reconstruction image made by Zhao Chuang shows the species Hamipterus tianshanensis according to the discoveries in a desert in Hami, northwest China’s Xinjiang Uygur Autonomous Region. Over 200 three-dimensionally preserved eggs of pterosaurs have been unearthed in China, providing new insight into the life history of the rulers of the skies in the age of dinosaurs. (Xinhua)

The pterosaur record is generally poor, and pterosaur eggs are even rarer. Only a handful of isolated occurrences of eggs and embryos have been reported so far. Three-dimensionally preserved eggs include one from Argentina and five reported from the Turpan-Hami Basin, Xinjiang, northwestern China in 2014. Our understanding of several biological questions, including their ontogenetic development and reproductive strategy for pterosaurs is very limited.

After many extensive fieldwork in the past years, Dr. WANG Xiaolin, Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences (CAS), and his team reported on hundreds of three-dimensional (3D) pter m2m connectivity  osaur eggs of the species Hamipterus tianshanensis from a Lower Cretaceous site in the Turpan-Hami Basin, 16 of which contain embryonic remains, allowing for an unexpected look at the embryology and reproductive strategy of these flying reptiles. Their study was published online 30 November in Science.

“The specimens can be attributed to Hamipterus tianshanensis, the sole species in this bonebed. The most important section is a sandstone block (3.28 m2) that yielded 215 eggs, but up to 300 may be present, because several more appear to be buried under the exposed ones,” said Dr. WANG Xiaolin, lead author of the study and project designer of the IVPP.

The eggs are in an accumulation without a preferential orientation, clearly showing transport. Their external surface shows crackin 3g  g and crazing, and all are deformed to a certain extent, which indicate their pliable nature. Although most eggs are complete, small fissures resulting from decomposition and compression during burial must have occurred because all eggs are filled with sandstone, which ultimately accounts for their three-dimensionality.

Internal content could be observed in 42 eggs, either through computed tomography (CT) scanning or micropreparation. From these, 16 had embryonic remains (38% of the sample). Bones are distributed along the egg, and mostly disarticulated and displaced from their natural position.

No embryo is complete, with osteological material varying from one to several bones. This can be explained by several factors, including the presence of embryos in distinct embryological stages, differential preservation of bones, and loss of elements during transport and burial, with part of the egg content expelled. The skull roof was not well ossified before the animal hatched, and no teeth were found in any of the embryos.

More than 200 eggs of Hamipterus tianshanensis preserved in sandstones (IVPP V 18941 to 18943), scale bar 200 mm. Image by WANG Xiaolin

“Although the current available material cannot provide a complete view of the ontogenetic development of Hamipterus, and despite some uncertainty in regarding these embryos as representing late embryonic stages, some general observations can be made that considerably expand our knowledge about the embryology and ontogeny of pterosaurs,” said co-corresponding author Dr. Alexander Kellner, Department of Geology and Paleontology, Museu Nacional-Universidade Federal do Rio de Janeiro, Brazil, “computed tomography scanning, osteohistology, and micropreparation reveal that some bones lack extensive ossification in potentially late-term embryos, hatchlings were likely to move around but were not able to fly, leading to the hypothesis that Hamipterus might have been less precocious than previously assumed for flying reptiles in general and probably needed some parental care.”

Most eggs were collected from white to gray, middle- to fine-grained sandstones that were deposited in a fluvio-lacustrine environment where mudstone pellets and localized lenses of mudstone are present, suggesting that events of high energy such as storms have passed over a nesting site, which might have caused the eggs to be moved inside the lake where they floated for a short period of time, becoming concentrated and eventually buried along with disarticulated skeletons.

“Our findings further demonstrate the exceptional conditions ne intelligent substation  cessary for the preservation of such fragile material and can explain the notable paucity of pterosaur eggs and embryos in the paleontological record compared to other reptiles, because the preservation potential of soft-shelled specimens is regarded as very poor,” said co-author Dr. JIANG Shunxing of the IVPP.

“Furthermore, this occurrence implies colonial breeding for Hamipterus tianshanensis, as demonstrated by the osteohistological identification of individuals in different growth stages, a hypothesis previously speculated for pterosaurs on the basis of very limited evidence. Our discovery may indicate that gregarious behavior and potential nesting site fidelity might have been widespread among derived pterosaurs,” said Dr. JIANG Shunxing.

Publication: Xiaolin Wang, et al., “Egg accumulation with 3D embryos provides insight into the life history of a pterosaur,” Science 01 Dec 2017: Vol. 358, Issue 6367, pp. 1197-1201; DOI: 10.1126/science.aan2329

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The Southern Ocean, the vast belt of water circling Antarctica, is a turbulent part of the ocean conveyor, where vast reservoirs of heat and carbon may rise to the surface, interacting with the atmosphere. The region, researchers say, plays a critical role in climate change. Image: Google Earth

Researchers at MIT and Florida State University found evidence that the missing piece in the model of world’s oceans circulation of heat, water and carbon around the planet may lie in the Southern Ocean. Their research has lead them to draw up a new schematic for ocean circulation and according to their observations and models, the Southern Ocean is a site where strong winds dredge waters that play a role in climate change.

The world’s oceans act as a massive conveyor, circulating heat, water and carbon around the planet. This global system plays a key role in climate change, storing and releasing heat throughout the world. To study how this system affe Vending Touchscreen  cts climate, scientists have largely focused on the North Atlantic, a major basin where water sinks, burying carbon and heat deep in the ocean’s interior.

But what goes down must come back up, and it’s been a mystery where, and how, deep waters circulate back to the surface. Filling in this missing piece of the circulation, and developing theories and models that capture it, may help researchers understand and predict the ocean’s role in climate and climate change.

Recently, scientists have found evidence that the missing piece may lie in the Southern Ocean — the vast ribbon of water encircling Antarctica. The Southern Ocean, according to observations and models, is a site where strong winds blowing along the Antarctic Circumpolar Current dredge waters up from the depths.

“There’s a lot of carbon and heat in the interior ocean,” says John Marshall, the Cecil and Ida Green Professor of Oceanography at MIT. “The Southern Ocean is the window by which the interior of the ocean connects to the atmosphere above.”

Marshall and Kevin Speer, a professor of physical oceanography at Florida State University, have published a paper in Nature Geoscience in which they review past work, examine the Southern Ocean’s influence on climate and draw up a new schematic for ocean circulation.

A revised conveyor

For decades, a “conveyor belt” model, developed by paleoclimatologist Wallace Broecker, has served as a simple cartoon of ocean circulation. The diagram depicts warm water moving northward, plunging deep into the North Atlantic; then coursing south as cold water toward Antarctica; then back north again, where waters rise and warm in the North Pacific.

However, evidence has shown that waters rise to the surface not so much in the North Pacific, but in the Southern Ocean — a distinction that Marshall and Speer illustrate in their updated diagram.

A new schematic emphasizes the role of the Southern Ocean in the world’s ocean circulation. The upper regions of ocean circulation are fed predominantly by broad upwelling across surfaces at mid-depth over the main ocean basins (rising blue-green-yellow arrows). Upwelling to the ocean surface occurs mainly around Antarctica in the Southern Ocean (rising yellow-red arrows) with wind and eddies playing a central role. Image: John Marshall and Kevin Speer

Marshall says winds and eddies along the Southern Ocean drag deep waters — and any buried carbon — to the surface around Antarctica. He and Speer write that the updated diagram “brings the Southern Ocean to the forefront” of the global circulation system, highlighting its role as a powerful climate mediator.

Indeed, Marshall and Speer review evidence that the Southern Ocean may have had a part in thawing the planet out of the last Ice Age. While it’s unclear what caused Earth to warm initially, this warming may have driven surface wind patterns poleward, pulling up deep water and carbon — which would have been released into the atmosphere, further warming the climate.

Shifting winds

In a cooling world, it appears that winds shift slightly closer to the Equator, and are buffeted by the continents. In a warming world, winds shift toward the poles; in the Southern Ocean, unimpeded winds  router industrial  whip up deep waters. The researchers note that two manmade atmospheric trends — ozone depletion and greenhouse gas emissions from fossil fuels — have a large effect on winds over the Southern Ocean: As the ozone hole recovers, greenhouse gases rise and the planet warms, winds over the Southern Ocean are likely to shift, affecting the delicate balance at play. In the future, if the Southern Ocean experiences stronger winds displaced slightly south of their current position, Antarctica’s ice shelves may be more vulnerable to melting — a phenomenon that may also have contributed to the end of the Ice Age.

“There are huge reservoirs of carbon in the interior of the ocean,” Marshall says. “If the climate changes and makes it easier for that carbon to get into the atmosphere, then there will be an additional warming effect.”

Jorge Sarmiento, a professor of atmospheric and oceanic sciences at Princeton University, says the Southern Ocean has been a difficult area to study. To fully understand the Southern Ocean’s dynamics requires models with high resolution — a significant challenge, given the ocean’s size.

“Because it’s so hard to observe the Southern Ocean, we’re still in the process of learning things,” says Sarmiento, who was not involved with this research. “So I think this is a very nice snapshot of our current understanding, based on models and observations, and it will sort of be a touchstone for future developments in the field.”

Marshall and Speer are now working with a multi-institution team led by MIT’s collaborator, the Woods Hole Oceanographic Institution, to measure how waters upwell in the Southern Ocean. The researchers are studying the flow driven by eddies in the Antarctic Circumpolar Current, and have deployed tracers and deep drifters to measure its effects; temperature, salinity and oxygen content in the water also help tell them how eddies behave, and how quickly or slowly warm water rises to the surface.

“Any perturbation that is made to the atmosphere, whether it’s due to glacial cycles or ozone or greenhouse forcing, can change the b IIoT  alance over the Southern Ocean,” Marshall says. “We have to understand how the Southern Ocean works in the climate system and take that into account.”

Images: Google Earth; John Marshall and Kevin Speer

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This image is a graphical representation of the largest connected component of the network. Each node represents a unique individual. Red nodes identify subjects of a fatal or nonfatal gunshot injury; blue nodes represent people who were not subjects of gun violence. Data are from the Chicago Police Department.

New research from Yale University reveals how gun violence spreads over social networks through a process of social contagion.

Gun violence is often described as an epidemic or a public health concern, due to its alarmingly high levels in certain populations in the United States. It most often occurs within socially and economically disadvantaged minority urban communities, where rates of gun violence far exceed the national average. A new Yale study has established a model to predict how “contagious” the epidemic really is.

In a study published online on January 3 in the Journal of the American Medical Association, the researchers studied the probability of an individual becoming the victim of gun violence using an epidemiological approach.

Led by Andrew Papachristos, associate professor of sociology at Yale, the researchers analyzed a social network of individuals who were arrested during an 8-year period in Chicago, Illinois — a city that has rates of gun violence more than three times the national average. The team studied connections between people who were arrested together for the same offense, and found that more than 60% of all gun violence during this time period happened in “cascades” — or connected chains — through these particular social networks.

“We want to take this epidemic of gun violence out of the criminal justice paradigm and put it in a public health context that focuses on victims and the reduction of trauma,” says Papachristos, corresponding author on the study.

The study also determined that an individual within these social networks was at the greatest risk of being shot within a period of about 125 days after their “infector,” the person most responsible for exposing the subject to gun violence, was the subject of gun violence. These results provide evidence that gun violence is not just an epidemic, but it has specific network patterns that might provide plausible opportunities for interventions, notes Papachristos. “There is a real value in understanding the timing of these events as a way to identify victims, and where we can insert resources such as violence- and harm-reduction programs into these networks.”

“If we want to drop gun violence rates in this country, we have to care about the young men with criminal records who become victims of gun violence,” says Papachristos. “By and large these are young men of color who have criminal records. Their lives are worth saving.”

Other authors on the study included Ben Green ’14 and Thibaut Horel from Harvard University.

S ethernet switch  tudy: Ben Green, et al., “Mo remote PLC programming  deling Contagion Through Social Networks to E wireless networking  xplain and Predict Gunshot Violence in Chicago, 2006 to 2014,” JAMA Intern Med., 2017; doi:10.1001/jamainternmed.2016.8245

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Nucleons consist (left) of quarks (matter particles) and gluons (force particles). A glueball (right) is made up purely of gluons.

Scientists from Vienna University believe they may have discovered the long-sought-after glueball, a particle composed of pure force.

For decades, scientists have been looking for so-called “glueballs”. Now it seems they have been found at last. A glueball is an exotic particle, made up entirely of gluons – the “sticky” particles that keep nuclear particles together. Glueballs are unstable and can only be detected indirectly, by analyzing their decay. This decay process, however, is not yet fully understood.

Professor Anton Rebhan and Frederic Brünner from TU Wien (Vienna) have now employed a new theoretical approach to calculate glueball decay. Their results agree extremely well with data from particle accelerator experiments. This is strong evidence that a resonance called &ldquo VPN router  ;f0(1710)”, which has been found in various experiments, is in fact the long-sought glueball. Further experimental results are to be expected in the next few months.

Forces are Particles too

Protons and neutrons consist of even smaller elementary particles called quarks. These quarks are bound together by strong nuclear force. “In particle physics, every force is mediated by a special kind of force particle, and the force particle of the strong nuclear force is the gluon”, says Anton Rebhan (TU Wien).

Gluons can be seen as more complicated versions of the photon. The massless photons are responsible for the forces of electromagnetism, while eight different kinds of gluons play a similar role for the strong nuclear force. However, there is one important difference: gluons themselves are subject to their own force, photons are not. This is why there are no bound states of photons, but a particle that consists only of bound gluons, of pure nuclear force, is in fact possible.

In 1972, shortly after the theory of quarks and gluons was formulated, the physicists Murray Gell-Mann and Harald Fritsch speculated about possible bound states of pure gluons (originally called “gluonium”, today the term “glueball” is used). Several particles have been found in particle accelerator experiments which are considered to be viable candidates for glueballs, but there has never been a scientific consensus on whether or not one of these signals could in fact be the mysterious particle made of pure force. Instead of a glueball, the signals found in the experiments could also be a combination of quarks and antiquarks. Glueballs are too short-lived to detect them directly. If they exist, they have to be identified by studying their decay.

Candidate f0(1710) decays strangely

“Unfortunately, the decay pattern of glueballs cannot be calculated rigorously”, says Anton Rebhan. Simplified model calculations have shown that there are two realistic candidates for glueballs: the mesons called f0(1500) and f0(1710). For a long time, the former was considered to be the most promising candidate. The latter has a higher mass, which agrees better with computer simulations, but when it decays, it produces many heavy quarks (the so-called “strange quarks”). To many particle scientists, this seemed implausible, because gluon interactions do not usually differentiate between heavier and lighter quarks.

Anton Rebhan and his PhD-student Frederic Brünner have now made a major step forward in solving this puzzle by trying a different approach. There are fundamental connections between quantum theories describing the behavior of particles in our three dimensional world and certain kinds of gravitation theories in higher dimensional spaces. This means that certain quantum physical questions c secure web based scada  an be answered using tools from gravitational physics.

“Our calculations show that it is indeed possible for glueballs to decay predominantly into strange quarks”, says Anton Rebhan. Surprisingly, the calculated decay pattern into two lighter particles agrees extremely well with the decay pattern measured for f0(1710). In addition to that, other decays into more than two particles are possible. Their decay rates have been calculated too.

Further Data is Expected Soon

Up until now, these alternative glueball decays have not been measured, but within the next few months, two experiments at the Large Hadron Collider at CERN (TOTEM and LHCb) and one accelerator experiment in Beijing (BESIII) are expected to yield new data. “These results will be crucial for our theory”, says Anton Rebhan. “For these multi-particle processes, our theory predicts decay rates which are quite different from the predictions of other, simpler models. If the measurements agree with our calculations, this will be a remarkable success for our approach.” It would be overwhelming evidence for f0(1710) being a glueball. And in addition to that, it would once again show that higher dimensional gravity can be used to answer questions from particle physics – industrial iot   in a way it would be one more big success of Einstein’s theory of general relativity, which turns 100 years old next month.

Publication: Frederic Brünner and Anton Rebhan, “Nonchiral Enhancement of Scalar Glueball Decay in the Witten-Sakai-Sugimoto Model,” Phys. Rev. Lett., 2015, 115, 131601; doi:10.1103/PhysRevLett.115.131601

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When the waves are confined to a circular corral, they reflect back on  Android Industrial Computer  themselves, producing complex patterns (grey ripples) that steer the droplet in an apparently random trajectory (white line). But in fact, the droplet’s motion follows statistical patterns determined by the wavelength of the waves. Image: Dan Harris

MIT scientists uncover quantum behavior in fluid dynamics, offering a new perspective on wave-particle duality.

In the early days of quantum physics, in an attempt to explain the wavelike behavior of quantum particles, the French physicist Louis de Broglie proposed what he called a “pilot wave” theory. According to de Broglie, moving particles — such as electrons, or the photons in a beam of light — are borne along on waves of some type, like driftwood on a tide.

Physicists’ inability to detect de Broglie’s posited waves led them, for the most part, to abandon pilot-wave theory. Recently, however, a real pilot-wave system has been discovered, in which a drop of fluid bounces across a vibrating fluid bath, propelled by waves produced by its own collisions.

In 2006, Yves Couder and Emmanuel Fort, physicists at Université Paris Diderot, used this system to reproduce one of the most famous experiments in quantum physics: the so-called “double-slit” expe data terminal unit  riment, in which particles are fired at a screen through a barrier with two holes in it.

In the latest issue of the journal Physical Review E (PRE), a team of MIT researchers, in collaboration with Couder and his colleagues, report that they have produced the fluidic analogue of another classic quantum experiment, in which electrons are confined to a circular “corral” by a ring of ions. In the new experiments, bouncing drops of fluid mimicked the electrons’ statistical behavior with remarkable accuracy.

“This hydrodynamic system is subtle, and extraordinarily rich in terms of mathematical modeling,” says John Bush, a professor of applied mathematics at MIT and corresponding author on the new paper. “It’s the first pilot-wave system discovered and gives insight into how rational quantum dynamics might work, were such a thing to exist.”

Joining Bush on the PRE paper are lead author Daniel Harris, a graduate student in mathematics at MIT; Couder and Fort; and Julien Moukhtar, also of Université Paris Diderot. In a separate pair of papers, appearing this month in the Journal of Fluid Mechanics, Bush and Jan Molacek, another MIT graduate student in mathematics, explain the fluid mechanics that underlie the system’s behavior.

Interference inference

The double-slit experiment is seminal because it offers the clearest demonstration of wave-particle duality: As the theoretical physicist Richard Feynman once put it, “Any other situation in quantum mechanics, it turns out, can always be explained by saying, ‘You remember the case of the experiment with the two holes? It’s the same thing.’”

If a wave traveling on the surface of water strikes a barrier with two slits in it, two waves will emerge on the other side. Where the crests of those waves intersect, they form a larger wave; where a crest intersects with a trough, the fluid is still. A bank of pressure sensors struck by the waves would register an “interference pattern” — a series of alternating light and dark bands indicating where the waves reinforced or canceled each other.

Photons fired through a screen with two holes in it produce a similar interference pattern — even when they’re fired one at a time. That’s wave-particle duality: the mathematics of wave mechanics explains the statistical behavior of moving particles.

In the experiments reported in PRE, the researchers mounted a shallow tray with a circular depression in it on a vibrating stand. They filled the tray with a silicone oil and began vibrating it at a rate just below that required to produce surface waves.

They then dropped a single droplet of the same oil into the bath. The droplet bounced up and down, producing waves that pushed it along the surface.

The waves generated by the bouncing droplet reflected off the corral walls, confining the droplet within the circle and interfering with each other to create complicated patterns. As the droplet bounced off the waves, its motion appeared to be entirely random, but over time, it proved to favor certain regions of the bath over others. It was found most frequently near the center of the circle, then, with slowly diminishing frequency, in concentric rings whose distance from each other was determined by the wavelength of the pilot wave.

The statistical description of the droplet’s location is analogous to that of an electron confined to a circular quantum corral and has a similar, wavelike form.

“It’s a great result,” says Paul Milewski, a math professor at the University of Bath, in England, who specializes in fluid mechanics. “Given the number of quantum-mechanical analogues of this mechanical system already shown, it’s not an enormous surprise that the corral experiment also behaves like quantum mechanics. But they’ve done an amazingly careful job, because it takes very accurate measurements over a very long time of this droplet bouncing to get this probability distribution.”

“If you have a system that is deterministic and is what we call in the business ‘chaotic,’ or sensitive to initial conditions, sensitive to perturbations, then it can behave probabilistically,” Milewski continues. “Experiments like this weren’t available to the giants of quantum mechanics. They also didn’t know anything about chaos. Suppose these guys — who were puzzled by why the world behaves in this strange probabilistic way — actually had access to experiments like this and ha 3G 4G LTE  d the knowledge of chaos, would they have come up with an equivalent, deterministic theory of quantum mechanics, which is not the current one? That’s what I find exciting from the quantum perspective.”

Publication: Daniel M. Harris, et al., “Wavelike statistics from pilot-wave dynamics in a circular corral,” Phys. Rev. E 88, 011001(R) (2013); doi:10.1103/PhysRevE.88.011001

Related Publications:

Jan Molaceka1 and John W. M. Bush, “Drops bouncing on a vibrating bath,” Journal of Fluid Mechanics / Volume 727 / July 2013, pp 582-611; doi:10.1017/jfm.2013.279 Jan Molaceka1 and John W. M. Bush, “Drops walking on a vibrating bath: towards a hydrodynamic pilot-wave theory,” Journal of Fluid Mechanics / Volume 727 / July 2013, pp 612-647; doi:10.1017/jfm.2013.280

Image: Dan Harris

Reprinted with permission of MIT News

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Electron microscope image of a prototype chip using a ring of coupled oscillators to generate terahertz radiation. Silicon cannot oscillate in the terahertz range, but the design focuses most of the energy in a high harmonic. The signal radiates on the axis of the ring and can be aimed. Provided/Ehsan Afshari

A recently published paper describes how scientists at Cornell University developed a new method of generating terahertz signals using the familiar and inexpensive CMOS chip technology, generating power levels high enough for some medical applications.

Cornell researchers have developed a new method of generating terahertz signals on an inexpensive silicon chip, offering possible applications in medical imaging, security scanning and wireless data transfer.

Terahertz radiation, the portion of the electromagnetic spectrum between microwaves and infrared light, penetrates cloth and leather and just a few millimeters into the skin, but without the potentially damaging effects of X-rays. Terahertz scanning can identify sk cost-effective M2M router  in cancers too small to see with the naked eye. Many of the complex organic chemicals used in explosives absorb terahertz radiation at particular frequencies, creating a “signature” that detectors can read. And because higher frequencies can carry more bandwidth, terahertz signals could make a sort of super-Bluetooth that could transfer an entire high-definition movie wirelessly in a few seconds.

Current methods of generating terahertz radiation involve lasers, vacuum tubes and special circuits cooled near absolute zero, often in room-sized apparatus costing thousands of dollars. Ehsan Afshari, assistant professor of electrical and computer engineering, has Overhead Line Monitoring   developed a new method using the familiar and inexpensive CMOS chip technology, generating power levels high enough for some medical applications. With further research, higher power will be possible, Afshari said, enabling such devices as handheld scanners for law enforcement.

Afshari and graduate students Yahya Tousi and Vahnood Pourahma describe the new approach in the June 8 issue of the journal Physical Review Letters.

Schematic of a ring of oscillators (gray circles) coupled to generate terahertz frequencies. Coupling circuits (blue triangles) shift the phase of the oscillations to reinforce the fourth harmonic. Provided/Ehsan Afshari

The ability of solid-state devices to generate high frequencies is limited by the characteristics of the material — basically, how fast electrons can move back and forth in a transistor. So circuit designers make use of harmonics — signals that naturally appear at multiples of the fundamental frequency of an oscillator. That fundamental frequency is usually set by a circuit that uses a variable capacitor called a varactor, but at terahertz frequencies varactors don’t tune sharply. Afshari has come up with a new way of tuning by coupling several oscillators in a ring, producing what engineers call a high-quality signal, where all the power goes into a very narrow frequency band.

Connect two springs and set one vibrating, and the other will begin to vibrate as well, and eventually they will settle to an equilibrium. A ring of electronic oscillators does the same, and the circuits coupling the oscillators can set the frequency at which they will lock in. In Afshari’s device the couplers also shift the phase of the signals, that is, how the peaks an security  d valleys of the waves line up. With the right adjustment, the peaks and valleys cancel each other out at several harmonics but reinforce each other at one — in this case the fourth — channeling most of the power there.

In early experiments, the researchers fabricated chips that generated signals with about 10,000 times the power level previously obtained at terahertz frequencies on a silicon chip. The signal emerges along the axis of the ring, and what the researchers called an intriguing possibility is that by adjusting the couplers separately they could aim the output, making it possible to scan large areas with a narrow, high-powered beam.

The power could be increased by adding more oscillators to the ring or using multiple rings, and Afshari is working with Cornell experts on gallium nitride, a chip material that can handle both higher frequencies and higher power. But Afshari said he wants to focus on less-expensive silicon. “The goal is to make a complete device on one CMOS chip,” he said. “I can envision a tiny thing you could put in a cell phone.”

The research is funded by the National Science Foundation, the U.S. Office of Naval Research and the Semiconductor Research Corp., a consortium supported by private industry and the Defense Advanced Projects Research Administration.

Images: Provided/Ehsan Afshari; Cornell Chronicle