Researchers take a step toward novel quantum simulators

A scanning electron microscope image of the "two-island" device, which researchers hope will pave the way toward a quantum simulator. 
Image Credit: Winston Pouse/Stanford University

Some of the most exciting topics in modern physics, such as high-temperature superconductors and some proposals for quantum computers, come down to the exotic things that happen when these systems hover between two quantum states.

Unfortunately, understanding what's happening at those points, known as quantum critical points, has proved challenging. The math is frequently too hard to solve, and today's computers are not always up to the task of simulating what happens, especially in systems with any appreciable number of atoms involved.

Now, researchers at Stanford University and the Department of Energy's SLAC National Accelerator Laboratory and their colleagues have taken a step toward building an alternative approach, known as a quantum simulator. Although the new device, for now, only simulates the interactions between two quantum objects, the researchers argue in a paper published in Nature Physics that it could be scaled up relatively easily. If so, researchers could use it to simulate more complicated systems and begin answering some of the most tantalizing questions in physics. 

Engineers invent vertical, full-color microscopic LEDs

MIT engineers have developed a new way to make sharper, defect-free displays. Instead of patterning red, green, and blue diodes side by side in a horizontal patchwork, the team has invented a way to stack the diodes to create vertical, multicolored pixels.
Image Credit: Illustration by Younghee Lee

Take apart your laptop screen, and at its heart you’ll find a plate patterned with pixels of red, green, and blue LEDs, arranged end to end like a meticulous Lite Brite display. When electrically powered, the LEDs together can produce every shade in the rainbow to generate full-color displays. Over the years, the size of individual pixels has shrunk, enabling many more of them to be packed into devices to produce sharper, higher-resolution digital displays.

But much like computer transistors, LEDs are reaching a limit to how small they can be while also performing effectively. This limit is especially noticeable in close-range displays such as augmented and virtual reality devices, where limited pixel density results in a “screen door effect” such that users perceive stripes in the space between pixels.

Now, MIT engineers have developed a new way to make sharper, defect-free displays. Instead of replacing red, green, and blue light-emitting diodes side by side in a horizontal patchwork, the team has invented a way to stack the diodes to create vertical, multicolored pixels.

The moon is too hot and too cold; now it could be just right for humans, thanks to newly available science

Issam Mudawar’s research on heat transfer could enable space habitats to be built in extreme environments like the moon.
Photo Credit: Purdue University / John Underwood

With temperatures on the moon ranging from minus 410 to a scorching 250 degrees Fahrenheit, it’s an understatement to say that humans will need habitats with heat and air conditioning to survive there long term.

But heating and cooling systems won’t be effective enough to support habitats for lunar exploration or even longer trips to Mars without an understanding of what reduced gravity does to boiling and condensation. Engineers haven’t been able to crack this science – until now.

“Every refrigerator, every air conditioning system we have on Earth involves boiling and condensation. Those same mechanisms are also prevalent in numerous other applications, including steam power plants, nuclear reactors and both chemical and pharmaceutical industries,” said Issam Mudawar, Purdue University’s Betty Ruth and Milton B. Hollander Family Professor of Mechanical Engineering. “We have developed over a hundred years’ worth of understanding of how these systems work in Earth’s gravity, but we haven’t known how they work in weightlessness.”

A team of engineers at Purdue led by Mudawar, who is collaborating with NASA’s Glenn Research Center in Cleveland, has spent 11 years developing a facility to investigate these phenomena.

Serious eating disorder ARFID is highly heritable, according to new twin study

Cynthia Bulik, PhD, founding director of the UNC Center of Excellence for Eating Disorders, is senior author of the article published in JAMA Psychiatry.
Photo Credit: Courtesy of University of North Carolina School of Medicine

ARFID is a serious eating disorder that leads to malnutrition and nutritional deficiencies. Researchers estimate that between one to five percent of the population is affected by the eating disorder.

Unlike anorexia, ARFID is not about the patient’s experience of their own body and fear of gaining weight. Instead, the disease is characterized by the avoidance of certain types of food due to a sensory discomfort because of the characteristics or appearance of food, or for example, the fear of choking, a food poisoning phobia or lack of appetite.

17,000 pairs of twins involved in the study

Researchers at Karolinska Institutet and the University of North Carolina School of Medicine have now investigated the importance of genetic factors for developing ARFID. A cohort of almost 17,000 pairs of twins in Sweden born between 1992 and 2010 participated in the study. A total of 682 children with ARFID between the ages of six and twelve years could be identified.

A quasiparticle that can transfer heat under electrical control

Because thermal conductivity in this class of materials can be changed with application of an external electric field at room temperature, they hold promise for use in heat switches for everyday applications, like collection of solar power.
Photo Credit: American Public Power Association

Scientists have found the secret behind a property of solid materials known as ferroelectrics, showing that quasiparticles moving in wave-like patterns among vibrating atoms carry enough heat to turn the material into a thermal switch when an electrical field is applied externally.

A key finding of the study is that this control of thermal conductivity is attributable to the structure of the material rather than any random collisions among atoms. Specifically, the researchers describe quasiparticles called ferrons whose polarization changes as they “wiggle” in between vibrating atoms – and it’s that ordered wiggling and polarization, receptive to the externally applied electrical field, that dictates the material’s ability to transfer the heat at a different rate.

“We figured out that this change in position of these atoms, and the change of the nature of the vibrations, must carry heat, and therefore the external field which changes this vibration must affect the thermal conductivity,” said senior author Joseph Heremans, professor of mechanical and aerospace engineering, materials science and engineering, and physics at The Ohio State University. 

319-million-year-old fish preserves the earliest fossilized brain of a backboned animal

 

Video Credit: University of Michigan

The CT-scanned skull of a 319-million-year-old fossilized fish, pulled from a coal mine in England more than a century ago, has revealed the oldest example of a well-preserved vertebrate brain.

The brain and its cranial nerves are roughly an inch long and belong to an extinct bluegill-size fish. The discovery opens a window into the neural anatomy and early evolution of the major group of fishes alive today, the ray-finned fishes, according to the authors of a University of Michigan-led study scheduled for publication Feb. 1 in Nature.

The serendipitous find also provides insights into the preservation of soft parts in fossils of backboned animals. Most of the animal fossils in museum collections were formed from hard body parts such as bones, teeth and shells.

The CT-scanned brain analyzed for the new study belongs to Coccocephalus wildi, an early ray-finned fish that swam in an estuary and likely dined on small crustaceans, aquatic insects and cephalopods, a group that today includes squid, octopuses and cuttlefish. Ray-finned fishes have backbones and fins supported by bony rods called rays.

A new way to explore proton’s structure with neutrinos yields first results

One of two magnetic focusing horns used in the beamline at Fermilab that produces intense neutrino beams for MINERvA and other neutrino experiments.
Photo Credit: Reidar Hahn, Fermilab

Physicists used MINERvA, a Fermilab neutrino experiment, to measure the proton’s size and structure using a neutrino-scattering technique.

For the first time, particle physicists have been able to precisely measure the proton’s size and structure using neutrinos. With data gathered from thousands of neutrino-hydrogen scattering events collected by MINERvA, a particle physics experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory, physicists have found a new lens for exploring protons. The results were published today in the scientific journal Nature.

This measurement is also important for analyzing data from experiments that aim to measure the properties of neutrinos with great precision, including the future Deep Underground Neutrino Experiment, hosted by Fermilab.

“The MINERvA experiment has found a novel way for us to see and understand proton structure, critical both for our understanding of the building blocks of matter and for our ability to interpret results from the flagship DUNE experiment on the horizon,” said Bonnie Fleming, Fermilab deputy director for science and technology.

SwRI investigations reveal more evidence that Mimas is a stealth ocean world

Resized Image using AI by SFLORG
Image Credit: Courtesy of NASA/JPL/SSI/SwRI

When a Southwest Research Institute scientist discovered surprising evidence that Saturn’s smallest, innermost moon could generate the right amount of heat to support a liquid internal ocean, colleagues began studying Mimas’ surface to understand how its interior may have evolved. Numerical simulations of the moon’s Herschel impact basin, the most striking feature on its heavily cratered surface, determined that the basin’s structure and the lack of tectonics on Mimas are compatible with a thinning ice shell and geologically young ocean.

“In the waning days of NASA’s Cassini mission to Saturn, the spacecraft identified a curious libration, or oscillation, in Mimas’ rotation, which often points to a geologically active body able to support an internal ocean,” said SwRI’s Dr. Alyssa Rhoden, a specialist in the geophysics of icy satellites, particularly those containing oceans, and the evolution of giant planet satellite systems. She is the second author of a new Geophysical Research Letters paper on the subject. “Mimas seemed like an unlikely candidate, with its icy, heavily cratered surface marked by one giant impact crater that makes the small moon look much like the Death Star from Star Wars. If Mimas has an ocean, it represents a new class of small, ‘stealth’ ocean worlds with surfaces that do not betray the ocean’s existence.”

Soil tainted by air pollution expels carbon

How climate change is fueling itself
Photo Credit: Nöel Puebla

New UC Riverside research suggests nitrogen released by gas-powered machines causes dry soil to let go of carbon and release it back into the atmosphere, where it can contribute to climate change. 

Industrial manufacturing, agricultural practices, and significantly, vehicles, all burn fossil fuels that release nitrogen into the air. As a result, levels of nitrogen in Earth’s atmosphere have tripled since 1850. The research team wanted to understand whether this extra nitrogen is affecting soil’s ability to hold onto carbon and keep it from becoming a greenhouse gas.

“Because nitrogen is used as a fertilizer for plants, we expected additional nitrogen would promote plant growth as well as microbial activity, thereby increasing carbon put into soils,” said Peter Homyak, study co-author and assistant professor in UCR’s Department of Environmental Sciences. 

In dryland soil, the type that covers much of Southern California, this is not what they saw.

Instead, the team found that under certain conditions, extra nitrogen causes dryland soil to acidify and leach calcium. Calcium binds to carbon, and the two elements then leave the soil together. This finding is detailed in the journal Global Change Biology. 

Learning with all your senses: Multimodal enrichment as the optimal learning strategy of the future

Illustration Credit: John Hain

Neuroscientist Katharina von Kriegstein from Technische Universität Dresden and Brian Mathias from the University of Aberdeen have compiled extensive interdisciplinary findings from neuroscience, psychology, computer modelling and education on the topic of "learning" in a recent review article in the journal Trends in Cognitive Sciences. The results of the interdisciplinary review reveal the mechanisms the brain uses to achieve improved learning outcome by combining multiple senses or movements in learning. This kind of learning outcome applies to a wide variety of domains, such as letter and vocabulary acquisition, reading, mathematics, music, and spatial orientation.

Many educational approaches assume that integrating complementary sensory and motor information into the learning experience can enhance learning, for example gestures help in learning new vocabulary in foreign language classes. In her recent publication, neuroscientist Katharina von Kriegstein from Technische Universität Dresden and Brian Mathias of the University of Aberdeen summarize these methods under the term "multimodal enrichment." This means enrichment with multiple senses and movement. Numerous current scientific studies prove that multimodal enrichment can enhance learning outcomes. Experiments in classrooms show similar results.