Glimpses of Quantum Computing Phase Changes Show Researchers the Tipping Point

Tuning a quantum computer’s measurement rate provides hints of quantum phase transition

Researchers at Duke University and the University of Maryland have used the frequency of measurements on a quantum computer to get a glimpse into the quantum phenomena of phase changes – something analogous to water turning to steam.

By measuring the number of operations that can be implemented on a quantum computing system without triggering the collapse of its quantum state, the researchers gained insight into how other systems — both natural and computational — meet their tipping points between phases. The results also provide guidance for computer scientists working to implement quantum error correction that will eventually enable quantum computers to achieve their full potential.

The results appeared online in the journal Nature Physics.

When heating water to a boil, the movement of molecules evolves as the temperature changes until it hits a critical point when it starts to turn to steam. In a similar fashion, a quantum computing system can be increasingly manipulated in discrete time steps until its quantum state collapses into a single solution.

“There are deep connections between phases of matter and quantum theory, which is what’s so fascinating about it,” said Crystal Noel, assistant professor of electrical and computer engineering and physics at Duke. “The quantum computing system is behaving in the same way as quantum systems found in nature — like liquid changing to steam — even though it’s digital.”

Parasitic worms reveal new insights into the evolution of sex and sex chromosomes

Schematic picture designed by the authors: During evolution, different chromosome elements represented by the Lego bricks (NA, NB, NX..etc. in the figure) were added onto the ancestral sex chromosomes in different species, forming the great diversity of nematode sex chromosomes. These "Lego" combinations of chromosome elements are shown as corresponding colors for each ‘clade’ of nematode species.
Credit: Quzijian

Studying two highly divergent phyla of worms that contain numerous parasites that cause human and livestock diseases, the research group of Qi Zhou from the University of Vienna and Zhejiang University, sheds light on how sexual reproduction and subsequent great diversity of sex chromosomes might have evolved.

Animals or plants with separate sexes are widespread in nature, and result from independent transitions from their hermaphroditic ancestor. The actual mechanism involved in the transitions between asexual and sexual reproductive modes, in other words, how is sex originated, remains an important and unanswered question. Excluding insects, about one third of the animal species, such as earthworms, snails, and some teleosts, are hermaphroditic. A comparison with their relatives who have evolved separate sexes, might reveal, how this particular trait originated and evolved in animals.

A new paper in Nature Communications, published by Qi Zhou of Department of Neuroscience and Developmental Biology in University of Vienna and Zhejiang University in China, provides clues into how separate sexes originated and characterizes how sex chromosomes evolved in flatworms or roundworms.

NASA's Chandra Catches Pulsar in X-ray Speed Trap

G292.0+1.8: NASA's Chandra Catches Pulsar in X-ray Speed Trap
Credit: X-ray: NASA/CXC/SAO/L. Xi et al.; Optical: Palomar DSS2
Hi-Res Zoomable Image

A young pulsar is blazing through the Milky Way at a speed of over a million miles per hour. This stellar speedster, witnessed by NASA's Chandra X-ray Observatory, is one of the fastest objects of its kind ever seen. This result teaches astronomers more about how some of the bigger stars end their lives.

Pulsars are rapidly spinning neutron stars that are formed when some massive stars run out of fuel, collapse, and explode. This pulsar is racing through the remains of the supernova explosion that created it, called G292.0+1.8, located about 20,000 light-years from Earth.

"We directly saw motion of the pulsar in X-rays, something we could only do with Chandra's very sharp vision," said Xi Long of the Center for Astrophysics | Harvard & Smithsonian (CfA), who led the study. "Because it is so distant, we had to measure the equivalent of the width of a quarter about 15 miles away to see this motion."

To make this discovery, the researchers compared Chandra images of G292.0+1.8 taken in 2006 and 2016. From the change in position of the pulsar over the 10-year span, they calculated it is moving at least 1.4 million miles per hour from the center of the supernova remnant to the lower left. This speed is about 30% higher than a previous estimate of the pulsar's speed that was based on an indirect method, by measuring how far the pulsar is from the center of the explosion.

River Belt Discovery Helps Scientists Understand Ancient Rivers

A relative elevation map of the Susitna River in Alaska,
one of the 30 rivers that were mapped as part of the study.
Credit: Tian Dong.

Long after a river has dried up, its channel belt lives on.

Made up of swaths of sediment surrounding the river, channel belts, once hardened into rock, preserve the paths of rivers that once were. However, reconstructing details about an ancient river from channel belt deposits is a notoriously difficult task.

New research from scientists at The University of Texas at Austin is making progress on that front. Lead author Tian Dong, a postdoctoral researcher at the UT Jackson School of Geosciences, said that by analyzing modern rivers they have been able to come up with a rule that connects channel belts to river patterns, finding that, in general, the more channels a river has, the narrower its channel belt.

Since the physics of shaping rivers is the same over time and place, the rule should hold for ancient rivers and rivers on other planets, too, according to co-author Timothy Goudge, an assistant professor at the Jackson School.

“We can look at a river deposit from 100 million years ago on Earth or from 3.5 billion years ago on Mars and we can say something about what the actual river looked like,” he said.

The results were published in the journal Geology.

Researchers Model Accelerator Magnets' History Using Machine Learning Approach

A magnet on a test stand inside SLAC National Accelerator Laboratory. Researchers have created a machine-learning model that will help predict how magnets will perform during beam experiments, among other applications.
Credit: Scott Anderson, SLAC National Accelerator Laboratory

Knowing a magnet’s past will allow scientists to customize particle beams more precisely in the future. As accelerators stretch for higher levels of performance, understanding subtle effects, such as those introduced by magnetic history, is becoming more critical.

After a long day of work, you might feel tired or exhilarated. Either way, you are affected by what happened to you in the past.

Accelerator magnets are no different. What they went through – or what went through them, like an electric current – affects how they will perform in the future.

Without understanding a magnet’s past, researchers might need to fully reset them before starting a new experiment, a process that can take 10 or 15 minutes. Some accelerators have hundreds of magnets, and the process can quickly become time-consuming and costly.

Now a team of researchers from the Department of Energy’s SLAC National Accelerator Laboratory and other institutions have developed a powerful mathematical technique that uses concepts from machine learning to model a magnet’s previous states and make predictions about future states. This new approach eliminates the need to reset the magnets and results in improvements in accelerator performance immediately.

Bringing back native predators to tackle invasive species crisis

Source: Queen's University Belfast

Invasive species are one of the greatest threats to biodiversity globally and are the main cause for the extinction of vertebrates in the last century, with an estimated cost of at least $162 billion (USD) a year.

Native predator populations have been depleted globally, despite being essential for the functioning of the ecosystem and biodiversity. The absence of native predators facilitates the spread of invasive species leading to the extinction of native species throughout the world.

The research, published today in Global Change Biology, found that restoring native predators could provide a solution to a variety of the most damaging invasive species globally. According to the study, the evolutionary naivety of invasive species to native predators, coupled with a lack of spatial refuges from predation could underpin the abilities of native predators to provide effective control of certain established invasive species.

The research team have previously shown how the recovery of the native pine marten in the UK and Ireland has resulted in landscape-scale declines of the invasive grey squirrel. Building on this research, the team have now evaluated native predator reintroduction and restoration as a viable nature-based solution to the invasive species crisis.

Researchers discover long-extinct giant dwarf crocodile species

Researchers led by the University of Iowa have discovered two new species of crocodiles that roamed parts of Africa between 18 million and 15 million years ago and preyed on human ancestors. The Kinyang giant dwarf crocodiles (in gold) were up to four times the length of their modern relatives, dwarf crocodiles (shown in green). The new species discovery comes after analysis of the skull of a Kinyang specimen.
Credit: Christopher Brochu, University of Iowa.

Millions of years ago, giant dwarf crocodiles roamed a part of Africa with a taste for our human ancestors.

In a new study, researchers led by the University of Iowa announced the discovery of two new species of crocodiles that roamed east Africa between 15 million and 18 million years ago before mysteriously disappearing. The species, called giant dwarf crocodiles, are related to dwarf crocodiles currently found in central and west Africa.

But the giant dwarf crocodiles were a lot bigger—hence, the name—than their modern relatives. Dwarf crocodiles rarely exceed 4 or 5 feet in length, but the ancient forms measured as long as 12 feet and likely were among the fiercest threats to any animal they encountered.

“These were the biggest predators our ancestors faced,” says Christopher Brochu, professor in the Department of Earth and Environmental Sciences at Iowa and the study’s corresponding author. “They were opportunistic predators, just as crocodiles are today. It would have been downright perilous for ancient humans to head down to the river for a drink.”

Chemists Created a Sensor that Accurately Detects the Saliva pH Level

Timofey Moseev has been engaged in research work since 2015.
Credit: Regina Pidgaetskaya

Chemists at UrFU have created a sensor for determining the pH of human saliva. This is a fluorophore with strong and stable emission, which picks up the smallest fluctuations in the pH in biological fluids (tenths). The analysis is performed using microdoses of the substance and a spectrometer, in which the substance is irradiated with a special lamp (its lifetime is tens of thousands of hours). The pH data appears in 5-7 seconds. The first results of joint studies of saliva samples and the sensor, conducted by scientific groups of the Department of Organic and Biomolecular Chemistry and the Department of Analytical Chemistry of the Institute of Chemical Engineering, are described in the famous Dyes and Pigments journal.

"Modern fluorometric pH sensors are based on small organic molecules. Typically, they are very sensitive and are able to detect the desired analyte in very low concentrations, up to nanoconcentrations. Our sensor is based on a new compound. We introduced a fluorinated fragment, and this allowed us to get the photophysical and electrochemical properties we needed," explains Timofey Moseev, an engineer-researcher at the Department of Organic and Biomolecular Chemistry at UrFU.

Saliva pH analysis is an accessible and non-invasive method of clinical diagnosis. With its help at an early stage, you can detect diseases, in particular gastrointestinal diseases: gastritis, stomach ulcers, duodenitis, etc. The pH level also affects the teeth: even a slight increase in the acidity of saliva can cause tooth decay and other problems.

Researchers develop the world's first ultra-fast photonic computing processor using polarization

Photonic computing processor chip
Credit: June Sang Lee

New research uses multiple polarization channels to carry out parallel processing – enhancing computing density by several orders over conventional electronic chips.

In a paper published in Science Advances, researchers at the University of Oxford have developed a method using the polarization of light to maximize information storage density and computing performance using nanowires.

Light has an exploitable property – different wavelengths of light do not interact with each other – a characteristic used by fiberoptic to carry parallel streams of data. Similarly, different polarizations of light do not interact with each other either. Each polarization can be used as an independent information channel, enabling more information to be stored in multiple channels, hugely enhancing information density.

First author and DPhil student June Sang Lee, Department of Materials, University of Oxford said: ‘We all know that the advantage of photonics over electronics is that light is faster and more functional over large bandwidths. So, our aim was to fully harness such advantages of photonics combining with tunable material to realize faster and denser information processing.’

AI detects autism speech patterns across different languages

The researchers believe their work could provide a tool that might one day transcend cultures, because of the computer’s ability to analyze words and sounds in a quantitative way regardless of language.
 Photo Credit: by Emily Wade on Unsplash

A new study led by Northwestern University researchers used machine learning — a branch of artificial intelligence — to identify speech patterns in children with autism that were consistent between English and Cantonese, suggesting that features of speech might be a useful tool for diagnosing the condition.

Undertaken with collaborators in Hong Kong, the study yielded insights that could help scientists distinguish between genetic and environmental factors shaping the communication abilities of people with autism, potentially helping them learn more about the origin of the condition and develop new therapies.

Children with autism often talk more slowly than typically developing children, and exhibit other differences in pitch, intonation and rhythm. But those differences (called “prosodic differences'' by researchers) have been surprisingly difficult to characterize in a consistent, objective way, and their origins have remained unclear for decades.

However, a team of researchers led by Northwestern scientists Molly Losh and Joseph C.Y. Lau, along with Hong Kong-based collaborator Patrick Wong and his team, successfully used supervised machine learning to identify speech differences associated with autism.