Researchers from the Austrian Academy of Sciences and the University of Vienna have experimentally demonstrated what was previously only a theoretical possibility. Together with quantum physicists from the University of Science and Technology of China, they have succeeded in teleporting complex high-dimensional quantum states. The research teams report this international first in the journal Physical Review Letters.

In their study, the researchers teleported the quantum state of one photon (light particle) to another distant one. Previously, only two-level states (“qubits”) had been transmitted, i.e., information with values “0” or “1”. However, the scientists succeeded in teleporting a three-level state, a so-called “qutrit”. In quantum physics, unlike in classical computer science, “0” and “1” are not an ‘either/or’ – both simultaneously, or anything in between, is also possible. The Austrian-Chinese team has now demonstrated this in practice with a third possibility “2”.

[…]

The quantum state to be teleported is encoded in the possible paths a photon can take. One can picture these paths as three optical fibers. Most interestingly, in quantum physics a single photon can also be located in all three optical fibers at the same time. To teleport this three-dimensional quantum state, the researchers used a new experimental method. The core of quantum teleportation is the so-called Bell measurement. It is based on a multiport beam splitter, which directs photons through several inputs and outputs and connects all optical fibers together. In addition, the scientists used auxiliary photons—these are also sent into the multiple beam splitter and can interfere with the other photons.

Through clever selection of certain interference patterns, the quantum information can be transferred to another photon far from the input photon, without the two ever physically interacting. The experimental concept is not limited to three dimensions, but can in principle be extended to any number of dimensions, as Erhard emphasizes.

Higher information capacities for quantum computers

With this, the international research team has also made an important step towards practical applications such as a future quantum internet, since high-dimensional quantum systems can transport larger amounts of information than qubits. “This result could help to connect quantum computers with information capacities beyond qubits”, says Anton Zeilinger, quantum physicist at the Austrian Academy of Sciences and the University of Vienna, about the innovative potential of the new method.

[…]

In future work, the quantum physicists will focus on how to extend the newly gained knowledge to enable teleportation of the entire quantum state of a single photon or atom.

Source: Complex quantum teleportation achieved for the first time

thanks to the work of Shabir Barzanjeh at the Institute of Science and Technology Austria and a few colleagues. This team has used entangled microwaves to create the world’s first quantum radar. Their device, which can detect objects at a distance using only a few photons, raises the prospect of stealthy radar systems that emit little detectable electromagnetic radiation.

The device is simple in essence. The researchers create pairs of entangled microwave photons using a superconducting device called a Josephson parametric converter. They beam the first photon, called the signal photon, toward the object of interest and listen for the reflection.

In the meantime, they store the second photon, called the idler photon. When the reflection arrives, it interferes with this idler photon, creating a signature that reveals how far the signal photon has traveled. Voila—quantum radar!

This technique has some important advantages over conventional radar. Ordinary radar works in a similar way but fails at low power levels that involve small numbers of microwave photons. That’s because hot objects in the environment emit microwaves of their own.

In a room temperature environment, this amounts to a background of around 1,000 microwave photons at any instant, and these overwhelm the returning echo. This is why radar systems use powerful transmitters.

Entangled photons overcome this problem. The signal and idler photons are so similar that it is easy to filter out the effects of other photons. So it becomes straightforward to detect the signal photon when it returns.

Of course, entanglement is a fragile property of the quantum world, and the process of reflection destroys it.  Nevertheless, the correlation between the signal and idler photons is still strong enough to distinguish them from background noise.

[…]

A big advantage is the low levels of electromagnetic radiation required. “Our experiment shows the potential as a non-invasive scanning method for biomedical applications, e.g., for imaging of human tissues or non-destructive rotational spectroscopy of proteins,” say Barzanjeh and co.

Then there is the obvious application as a stealthy radar that is difficult for adversaries to detect over background noise. The researchers say it could be useful for short-range low-power radar for security applications in closed and populated environments.

Source: Quantum radar has been demonstrated for the first time – MIT Technology Review

We highlight the five most important takeaways from the IPCC’s recent 1,400+ page report on climate change and land use.

Source: Our Impact on Climate Change and Global Land Use in 5 Charts

A study led by University of Toronto researchers, published today in the American Heart Association journal Circulation: Cardiovascular Imaging, found that blood pressure can be measured accurately by taking a quick video selfie.

Kang Lee, a professor of applied psychology and human development at the Ontario Institute for Studies in Education and Canada Research Chair in developmental neuroscience, was the lead author of the study, working alongside researchers from the Faculty of Medicine’s department of physiology, and from Hangzhou Normal University and Zhejiang Normal University in China.

Using a technology co-discovered by Lee and his postdoctoral researcher Paul Zheng called transdermal optical imaging, researchers measured the blood pressure of 1,328 Canadian and Chinese adults by capturing two-minute videos of their faces on an iPhone. Results were compared to standard devices used to measure blood pressure.

The researchers found they were able to measure three types of blood pressure with 95 to 96 per cent accuracy.

[…]

Transdermal optical imaging works by capitalizing on the translucent nature of facial skin. When the light reaches the face, it penetrates the skin and reaches hemoglobin underneath it, which is red. This technology uses the optical sensor on a smartphone to capture the reflected red light from hemoglobin, which allows the technology to visualize and measure blood flow changes under the skin.

“From the video captured by the technology, you can see how the blood flows in different parts of the face and through this ebb and flow of blood in the face, you can get a lot of information,” says Lee.

He understood that the transdermal optical imaging technology had significant practical implications, so, with the help of U of T and MaRS, he formed a startup company called Nuralogix alongside entrepreneur Marzio Pozzuoli, who is now the CEO.

[…]

Nuralogix has developed a smartphone app called Anura that allows people to try out the transdermal optical imaging software for themselves. In the publicly available version of the app, people can record a 30-second video of their face and will receive measurements for stress levels and resting heart rate. In the fall, the company will release a version of the app in China that includes blood pressure measurements.

Lee says there is more research to be done to ensure that health measurements using transdermal optical imaging are as accurate as possible. In the recent study, for example, only people with regular or slightly higher blood pressure were measured. The study sample also did not have people with very dark or very fair skin. More diverse research subjects will make measurements more accurate, says Lee, but there are challenges when looking for people with very high and low blood pressure.

“In order to improve our app to make it usable, particularly for people with hypertension, we need to collect a lot of data from them, which is very, very hard because a lot of them are already taking medicine,” says Lee. “Ethically, we cannot tell them not to take medicine, but from time to time, we get participants who do not take medicine so we can get hypertensive and hypotensive people this way.”

While there are a wide range of applications for transdermal optical imaging technology, Lee says data privacy is of utmost concern. He says when a person uses the software by recording a video of their face, only the results are uploaded to the cloud but the video is not.

“We only extract blood flow information from your face and send that to the cloud. So from the cloud, if I look at your blood flow, I couldn’t tell it is you,” he says.

[…]

The research team also hopes to expand the capabilities of the technology to measure other health markers, including blood-glucose levels, hemoglobin and cholesterol.

Nuralogix plans on monetizing the technology by making an app that allows consumers to pay a low monthly fee to access more detailed health data. They are also licensing the technology through a product called DeepAffex, a cloud-based AI engine that can be used by businesses who are interested in the transdermal optical imaging technology in a range of industries from health care to security.

Source: Preventative health at your fingertips: U of T researchers accurately measure blood pressure using phone camera

The majority of YouTube videos about the climate crisis oppose the scientific consensus and “hijack” technical terms to make them appear credible, a new study has found. Researchers have warned that users searching the video site to learn about climate science may be exposed to content that goes against mainstream scientific belief.

Dr Joachim Allgaier of RWTH Aachen University in Germany analysed 200 YouTube videos to see if they adhered to or challenged the scientific consensus. To do so, he chose 10 search terms:

• Chemtrails
• Climate
• Climate change
• Climate engineering
• Climate hacking
• Climate manipulation
• Climate modification
• Climate science
• Geoengineering
• Global warming

The videos were then assessed to judge how closely they adhered to the scientific consensus, as represented by the findings of reports by UN Intergovernmental Panel on Climate Change (IPCC) from 2013 onwards.

These concluded that humans have been the “dominant cause” of global warming since the 1950s. However, Allgaier found that the message of 120 of the top 200 search results went against this view.

To avoid personalised results, Allgaier used the anonymisation tool Tor, which hides a computer’s IP address and means YouTube treats each search as coming from a different user.

The results for the search terms climate, climate change, climate science and global warming mostly reflected the scientific consensus view. Allgaier said this was because many contained excerpts from TV news programmes or documentaries.

The same could not be said for the results of searches related to chemtrails, climate engineering, climate hacking, climate manipulation, climate modification and geoengineering. Very few of these videos explained the scientific rationale behind their ideas, Allgaier said.

Source: Most YouTube climate change videos ‘oppose the consensus view’ | Technology | The Guardian

Using a technique to 3D-print liquids, the scientists created millimeter-size droplets from water, oil and iron-oxides. The liquid droplets keep their shape because some of the iron-oxide particles bind with surfactants — substances that reduce the surface tension of a liquid. The surfactants create a film around the liquid water, with some iron-oxide particles creating part of the filmy barrier, and the rest of the particles enclosed inside, Russell said.

The team then placed the millimeter-size droplets near a magnetic coil to magnetize them. But when they took the magnetic coil away, the droplets demonstrated an unseen behavior in liquids — they remained magnetized. (Magnetic liquids called ferrofluids do exist, but these liquids are only magnetized when in the presence of a magnetic field.)

When those droplets approached a magnetic field, the tiny iron-oxide particles all aligned in the same direction. And once they removed the magnetic field, the iron-oxide particles bound to the surfactant in the film were so jam-packed that they couldn’t move and so remained aligned. But those free-floating inside the droplet also remained aligned.

The scientists don’t fully understand how these particles hold onto the field, Russell said. Once they figure that out, there are many potential applications. For example, Russell imagines printing a cylinder with a non-magnetic middle and two magnetic caps. “The two ends would come together like a horseshoe magnet,” and be used as a mini “grabber,” he said.

In an even more bizarre application, imagine a mini liquid person — a smaller-scale version of the liquid T-1000 from the second “Terminator” movie — Russell said. Now imagine that parts of this mini liquid man are magnetized and parts aren’t. An external magnetic field could then force the little person to move its limbs like a marionette.

“For me, it sort of represents a sort of new state of magnetic materials,” Russell said. The findings were published on July 19 in the journal Science.

Source: In a Lab Accident, Scientists Create the First-Ever Permanently Magnetic Liquid

The scientific consensus that humans are causing global warming is likely to have passed 99%, according to the lead author of the most authoritative study on the subject, and could rise further after separate research that clears up some of the remaining doubts.

Three studies published in Nature and Nature Geoscience use extensive historical data to show there has never been a period in the last 2,000 years when temperature changes have been as fast and extensive as in recent decades.

It had previously been thought that similarly dramatic peaks and troughs might have occurred in the past, including in periods dubbed the Little Ice Age and the Medieval Climate Anomaly. But the three studies use reconstructions based on 700 proxy records of temperature change, such as trees, ice and sediment, from all continents that indicate none of these shifts took place in more than half the globe at any one time.

The Little Ice Age, for example, reached its extreme point in the 15th century in the Pacific Ocean, the 17th century in Europe and the 19th century elsewhere, says one of the studies. This localisation is markedly different from the trend since the late 20th century when records are being broken year after year over almost the entire globe, including this summer’s European heatwave.

[…]

“There is no doubt left – as has been shown extensively in many other studies addressing many different aspects of the climate system using different methods and data sets,” said Stefan Brönnimann, from the University of Bern and the Pages 2K consortium of climate scientists.

Commenting on the study, other scientists said it was an important breakthrough in the “fingerprinting” task of proving how human responsibility has changed the climate in ways not seen in the past.

“This paper should finally stop climate change deniers claiming that the recent observed coherent global warming is part of a natural climate cycle. This paper shows the truly stark difference between regional and localised changes in climate of the past and the truly global effect of anthropogenic greenhouse emissions,” said Mark Maslin, professor of climatology at University College London.

Previous studies have shown near unanimity among climate scientists that human factors – car exhausts, factory chimneys, forest clearance and other sources of greenhouse gases – are responsible for the exceptional level of global warming.

A 2013 study in Environmental Research Letters found 97% of climate scientists agreed with this link in 12,000 academic papers that contained the words “global warming” or “global climate change” from 1991 to 2011. Last week, that paper hit 1m downloads, making it the most accessed paper ever among the 80+ journals published by the Institute of Physics, according to the authors.

Source: ‘No doubt left’ about scientific consensus on global warming, say experts | Science | The Guardian

“While neuronally encoded behavior isn’t thought to be inherited across generations, we wanted to test the possibility that environmentally triggered modifications could allow ‘memory’ of parental experiences to be inherited,” explains Julianna “Lita” Bozler, a Ph.D. candidate in the Bosco Lab at the Geisel School of Medicine, who served as lead author on the study.

When exposed to parasitoid wasps—which deposit their eggs into and kill the larvae of fruit flies—Drosophila melanogaster females are known to shift their preference to food containing ethanol as an egg laying substrate, which protects their larvae from wasp infection.

For the study, the fruit flies were cohabitated with female wasps for four days before their eggs were collected. The embryos were separated into two cohorts—a wasp-exposed and unexposed (control) group—and developed to maturity without any contact with adult flies or wasps. One group was used to propagate the next generation and the other was analyzed for ethanol preference.

“We found that the original wasp-exposed flies laid about 94 percent of their eggs on ethanol food, and that this behavior persisted in their offspring, even though they’d never had direct interaction with wasps,” says Bozler.

The ethanol preference was less potent in the first-generation offspring, with 73 percent of their eggs laid on ethanol food. “But remarkably, this inherited ethanol preference persisted for five generations, gradually reverting back to a pre-wasp exposed level,” she says. “This tells us that inheritance of ethanol preference is not a permanent germline change, but rather a reversible trait.”

Importantly, the research team determined that one of the critical factors driving ethanol preference behavior is the depression of Neuropeptide-F (NPF) that is imprinted in a specific region of the female fly’s brain. While this change, based in part on visual signals, was required to initiate transgenerational inheritance, both male and female progeny were able to pass on ethanol preference to their offspring.

Source: Study finds that parental ‘memory’ is inherited across generations

Indoor levels of carbon dioxide could be clouding our thinking and may even pose a wider danger to human health, researchers say.

While air pollutants such as tiny particles and nitrogen oxides have been the subject of much research, there have been far fewer studies looking into the health impact of CO₂.

However, the authors of the latest study – which reviews current evidence on the issue – say there is a growing body of research suggesting levels of CO₂ that can be found in bedrooms, classrooms and offices might have harmful effects on the body, including affecting cognitive performance.

“There is enough evidence to be concerned, not enough to be alarmed. But there is no time to waste,” said Dr Michael Hernke, a co-author of the study from the University of Wisconsin-Madison, stressing further research was needed.

Writing in the journal Nature Sustainability, Hernke and colleagues report that they considered 18 studies of the levels of CO₂ humans are exposed to, as well as its health impacts on both humans and animals.

Traditionally, the team say, it had been thought that CO₂ levels would need to reach a very high concentration of at least 5,000 parts per million (ppm) before they would affect human health. But a growing body of research suggests CO₂ levels as low as 1,000ppm could cause health problems, even if exposure only lasts for a few hours.

The team say crowded or poorly ventilated classrooms, office environments and bedrooms have all been found to have levels of CO₂ that exceed 1,000ppm, and are spaces that people often remain in for many hours at a time. Air-conditioned trains and planes have also been found to exceed 1,000ppm.

[…]

The team found a number of studies have looked at the impact of such levels on human cognitive performance and productivity. In one study of 24 employees, cognitive scores were 50% lower when the participants were exposed to 1,400ppm of CO₂ compared with 550ppm during a working day.

The team additionally looked at the impact of CO₂ levels on animals, finding that a few hours’ exposure to 2,000 ppm was linked to inflammatory responses that could lead to damage to blood vessels. There is also tentative evidence suggesting that prolonged exposure to levels between 2,000 and 3,000ppm is linked to effects including stress, kidney calcification and bone demineralisation.

Source: Indoor carbon dioxide levels could be a health hazard, scientists warn | Environment | The Guardian

Another reason to limit creation of it

Researchers in a warming Arctic are discovering organisms, frozen and presumed dead for millennia, that can bear life anew. These ice age zombies range from simple bacteria to multicellular animals, and their endurance is prompting scientists to revise their understanding of what it means to survive.

“You wouldn’t assume that anything buried for hundreds of years would be viable,” said La Farge, who researches mosses at the University of Alberta. In 2009, her team was scouring Teardrop’s margin to collect blackened plant matter spit out by the shrinking glacier. Their goal was to document the vegetation that long ago formed the base of the island’s ecosystem.

“The material had always been considered dead. But by seeing green tissue, “I thought, ‘Well, that’s pretty unusual,’ ” La Farge said about the centuries-old moss tufts she found.

She brought dozens of these curious samples back to Edmonton, lavishing them with nutrient-rich soils in a bright, warm laboratory. Almost a third of the samples burst forth with new shoots and leaves. “We were pretty blown away,” La Farge said. The moss showed few ill effects of its multi-centennial deep-freeze.

[,,,]

Tatiana Vishnivetskaya has studied ancient microbes long enough to make the extreme feel routine. A microbiologist at the University of Tennessee, Vishnivetskaya drills deep into the Siberian permafrost to map the web of single-celled organisms that flourished ice ages ago. She has coaxed million-year-old bacteria back to life on a petri dish. They look “very similar to bacteria you can find in cold environments (today),” she said.

But last year, Vishnivetskaya’s team announced an “accidental finding” – one with a brain and nervous system – that shattered scientists’ understanding of extreme endurance.

As usual, the researchers were seeking singled-celled organisms, the only life-forms thought to be viable after millennia locked in the permafrost. They placed the frozen material on petri dishes in their room-temperature lab and noticed something strange. Hulking among the puny bacteria and amoebae were long, segmented worms complete with a head at one end and anus at the other – nematodes.

“Of course we were surprised and very excited,” Vishnivetskaya said. Clocking in at a half-millimeter long, the nematodes that wriggled back to life were the most complex creatures Vishnivetskaya – or anyone else – had ever revived after a lengthy deep freeze.

She estimated one nematode to be 41,000 years old – by far the oldest living animal ever discovered.

Source: Ancient life awakens amid thawing ice caps and permafrost – SFGate

Scientists have long known about such properties of light as wavelength. More recently, researchers have found that light can also be twisted, a property called angular momentum. Beams with highly structured angular momentum are said to have orbital angular momentum (OAM), and are called vortex beams. They appear as a helix surrounding a common center, and when they strike a flat surface, they appear as doughnut-shaped. In this new effort, the researchers were working with OAM beams when they found the light behaving in a way that had never been seen before.

The experiments involved firing two lasers at a cloud of argon gas—doing so forced the beams to overlap, and they joined and were emitted as a single beam from the other side of the argon cloud. The result was a type of vortex beam. The researchers then wondered what would happen if the lasers had different orbital angular momentum and if they were slightly out of sync. This resulted in a beam that looked like a corkscrew with a gradually changing twist. And when the beam struck a flat surface, it looked like a crescent moon. The researchers noted that looked at another way, a single photon at the front of the beam was orbiting around its center more slowly than a photon at the back of the beam. The researchers promptly dubbed the new property self-torque—and not only is it a newly discovered property of light, it is also one that has never even been predicted.

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The researchers suggest that it should be possible to use their technique to modulate the orbital angular momentum of light in ways very similar to modulating frequencies in communications equipment. This could lead to the development of novel devices that make use of manipulating extremely tiny materials.

Source: New property of light discovered

Researchers from the Yokohama National University have teleported quantum information securely within the confines of a diamond. The study has big implications for quantum information technology—the future of sharing and storing sensitive information. The researchers published their results on June 28, 2019, in Communications Physics.

“Quantum teleportation permits the transfer of quantum information into an otherwise inaccessible space,” said Hideo Kosaka, a professor of engineering at Yokohama National University and an author on the study. “It also permits the transfer of information into a quantum memory without revealing or destroying the stored quantum information.”

The inaccessible space, in this case, consisted of carbon atoms in diamond. Made of linked, yet individually contained, carbon atoms, a diamond holds the perfect conditions for quantum teleportation.

A carbon atom holds six protons and six neutrons in its nucleus, surrounded by six spinning electrons. As the atoms bond into a diamond, they form a notably strong lattice. However, diamonds can have complex defects, such as when a nitrogen atom exists in one of two adjacent vacancies where carbon atoms should be. This defect is called a nitrogen vacancy center.

Surrounded by carbon atoms, the nucleus structure of the nitrogen atom creates what Kosaka calls a nanomagnet.

To manipulate an electron and a carbon isotope in the vacancy, Kosaka and the team attached a wire about a quarter the width of a human hair to the surface of a diamond. They applied a microwave and a radio wave to the wire to build an oscillating magnetic field around the diamond. They shaped the microwave to create the optimal, controlled conditions for the transfer of quantum information within the diamond.

Kosaka then used the nitrogen nanomagnet to anchor an electron. Using the microwave and radio waves, Kosaka forced the electron spin to entangle with a carbon nuclear spin—the angular momentum of the electron and the nucleus of a carbon atom. The electron spin breaks down under a magnetic field created by the nanomagnet, making it susceptible to entanglement. Once the two pieces are entangled, meaning their physical characteristics are so intertwined they cannot be described individually, a photon that holds quantum information is introduced, and the electron absorbs the photon. The absorption allows the polarization state of the photon to be transferred into the carbon, which is mediated by the entangled electron, demonstrating a teleportation of information at the quantum level.

“The success of the photon storage in the other node establishes the entanglement between two adjacent nodes,” Kosaka said. Called quantum repeaters, the process can take individual chunks of information from node to node, across the quantum field.

“Our ultimate goal is to realize scalable quantum repeaters for long-haul quantum communications and distributed quantum computers for large-scale quantum computation and metrology,” Kosaka said.

Source: Researchers teleport information within a diamond

A novel magnet half the size of a cardboard toilet tissue roll usurped the title of “world’s strongest magnetic field” from the metal titan that had held it for two decades at the Florida State University-headquartered National High Magnetic Field Laboratory.

And its makers say we ain’t seen nothing yet: By packing an exceptionally high-field magnet into a coil you could pack in a purse, MagLab scientists and engineers have shown a way to build and use electromagnets that are stronger, smaller and more versatile than ever before.

Their work is outlined in an article published today in the journal Nature.

“We are really opening a new door,” said MagLab engineer Seungyong Hahn, the mastermind behind the new magnet and an associate professor at the FAMU-FSU College of Engineering. “This technology has a very good potential to entirely change the horizons of high-field applications because of its compact nature.”

[…]

Both the 45-T magnet and the 45.5-T test magnet are built in part with superconductors, a class of conductors boasting special properties, including the ability to carry electricity with perfect efficiency.

The superconductors used in the 45-T are niobium-based alloys, which have been around for decades. But in the 45.5-T proof-of-principle magnet, Hahn’s team used a newer compound called REBCO (rare earth barium copper oxide) with many advantages over conventional superconductors.

Notably, REBCO can carry more than twice as much current as a same-sized section of niobium-based superconductor. This current density is crucial: After all, the electricity running through an electromagnet generates its field, so the more you can cram in, the stronger the field.

Also critical was the specific REBCO product used—paper-thin, tape-shaped wires manufactured by SuperPower Inc.

MagLab Chief Materials Scientist David Larbalestier, who is also a professor at the FAMU-FSU College of Engineering, saw the product’s promise to pack more power into a potential world-record magnet, and encouraged Hahn to give it a go.

The other key ingredient was not something they put in, but rather something they left out: insulation.

Today’s electromagnets contain insulation between conducting layers, which directs the current along the most efficient path. But it also adds weight and bulk.

Hahn’s innovation: A superconducting magnet without insulation. In addition to yielding a sleeker instrument, this design protects the magnet from a malfunction known as a quench. Quenches can occur when damage or imperfections in the conductor block the current from its designated path, causing the material to heat up and lose its superconducting properties. But if there is no insulation, that current simply follows a different path, averting a quench.

“The fact that the turns of the coil are not insulated from each other means that they can share current very easily and effectively in order to bypass any of these obstacles,” explained Larbalestier, corresponding author on the Nature paper.

There’s another slimming aspect of Hahn’s design that relates to quenches: Superconducting wires and tapes must incorporate some copper to help dissipate heat from potential hot spots. His “no-insulation” coil, featuring tapes a mere 0.043-mm thick, requires much less copper than do conventional magnets.

Source: National MagLab creates world-record magnetic field with small, compact coil

Yale researchers have figured out how to catch and save Schrödinger’s famous cat, the symbol of quantum superposition and unpredictability, by anticipating its jumps and acting in real time to save it from proverbial doom. In the process, they overturn years of cornerstone dogma in quantum physics.

The discovery enables researchers to set up an early warning system for imminent jumps of artificial atoms containing quantum information. A study announcing the discovery appears in the June 3 online edition of the journal Nature.

[…]

The quantum jump is the discrete (non-continuous) and random change in the state when it is observed.

The experiment, performed in the lab of Yale professor Michel Devoret and proposed by lead author Zlatko Minev, peers into the actual workings of a quantum jump for the first time. The results reveal a surprising finding that contradicts Danish physicist Niels Bohr’s established view—the jumps are neither abrupt nor as random as previously thought.

For a tiny object such as an electron, molecule, or an artificial atom containing quantum information (known as a qubit), a quantum jump is the sudden transition from one of its discrete energy states to another. In developing quantum computers, researchers crucially must deal with the jumps of the qubits, which are the manifestations of errors in calculations.

The enigmatic quantum jumps were theorized by Bohr a century ago, but not observed until the 1980s, in atoms.

“These jumps occur every time we measure a qubit,” said Devoret, the F.W. Beinecke Professor of Applied Physics and Physics at Yale and member of the Yale Quantum Institute. “Quantum jumps are known to be unpredictable in the long run.”

“Despite that,” added Minev, “We wanted to know if it would be possible to get an advance warning signal that a jump is about to occur imminently.”

Minev noted that the experiment was inspired by a theoretical prediction by professor Howard Carmichael of the University of Auckland, a pioneer of quantum trajectory theory and a co-author of the study.

In addition to its fundamental impact, the discovery is a potential major advance in understanding and controlling quantum information. Researchers say reliably managing quantum data and correcting errors as they occur is a key challenge in the development of fully useful quantum computers.

The Yale team used a special approach to indirectly monitor a superconducting artificial atom, with three microwave generators irradiating the atom enclosed in a 3-D cavity made of aluminum. The doubly indirect monitoring method, developed by Minev for superconducting circuits, allows the researchers to observe the atom with unprecedented efficiency.

Microwave radiation stirs the artificial atom as it is simultaneously being observed, resulting in quantum jumps. The tiny quantum signal of these jumps can be amplified without loss to room temperature. Here, their signal can be monitored in real time. This enabled the researchers to see a sudden absence of detection photons (photons emitted by an ancillary state of the atom excited by the microwaves); this tiny absence is the advance warning of a quantum jump.

“The beautiful effect displayed by this experiment is the increase of coherence during the jump, despite its observation,” said Devoret. Added Minev, “You can leverage this to not only catch the jump, but also reverse it.”

This is a crucial point, the researchers said. While quantum jumps appear discrete and random in the long run, reversing a quantum jump means the evolution of the quantum state possesses, in part, a deterministic and not random character; the jump always occurs in the same, predictable manner from its random starting point.

“Quantum jumps of an atom are somewhat analogous to the eruption of a volcano,” Minev said. “They are completely unpredictable in the long term. Nonetheless, with the correct monitoring we can with certainty detect an advance warning of an imminent disaster and act on it before it has occurred.

Source: Physicists can predict the jumps of Schrodinger’s cat (and finally save it)

To catch and reverse a quantum jump mid-flight

Physicists have confirmed predictions of Stephen Hawking’s namesake theory of black holes using a black hole they constructed in their lab, according to a new paper.

This black hole isn’t like the black holes out in space, where gravity creates a region of spacetime so warped that light can’t escape. Instead, the researchers built a black hole analog using a strange quantum material called a Bose-Einstein condensate, in which the point of no return is for sound rather than light. Still, it’s an important verification Hawking’s work.

“I’m interested in learning whatever we can about real black holes and real gravity,” study author Jeff Steinhauer, physicist at the Technion-Israel Institute of Technology, told Gizmodo.

Stephen Hawking’s landmark theory is called Hawking radiation. When trying to apply the physical laws governing heat to black holes, he realized that black holes must emit radiation from their surfaces. The mechanism marks a combination of quantum mechanics (the science of the smallest things) with gravity (the science of interactions between the most massive things). But astronomers haven’t been able to peer close enough to a black hole to prove or disprove the theory. Some scientists have instead turned to analogues in the lab.

The scientists created an elongated Bose-Einstein condensate by trapping 8,000 rubidium atoms in a focused laser beam. Bose-Einstein condensates are systems of ultra-cold atoms where strange quantum physical phenomena become more visible on larger scales. They are often used for analog-type experiments like these.

A second laser increases the potential energy on one side of the Bose-Einstein condensate, making it denser on that side. A sharp transition separates the denser area (considered to be outside the black hole) and the less dense area (inside the black hole). This transition moves at a constant speed through the condensate, but from the point of view of the experimenters, it appears to be stationary; instead, it looks as if all of the rubidium atoms are moving. Outside the black hole in the denser region, the speed of sound is faster than the speed of this flow, so sound waves can move in either direction. But in the less dense region—inside the black hole—the speed of sound is slower, so sound waves only travel away from the sharp transition and further into the black hole, as described in the paper published in Nature.

This experiment mimics one of the most important features of the black hole—outside the black hole, light can either move away from or into the black hole. But once inside the black hole, it cannot escape. The laboratory analogue replaces light with sound, and the researchers can measure sound waves both outside and inside inside their black hole’s “event horizon.” The signal of the Hawking radiation is a correlation between these two kinds of waves.

Steinhauer’s team previously observed Hawking radiation in this system back in 2016. But this time around, they made at least 21 improvements to the system in order to get a better signal. This was enough to pull out important information about the system’s radiation, namely that it has a thermal spectrum with a temperature determined only by the system’s analogous equivalent to gravity, a relationship between the speed of sound and its flow. This means that it emitted a continuous spectrum of wavelengths, rather than preferred wavelengths. These observations, and the temperatures, were exactly as predicted in Hawking’s theories.

“The way I see it, what we saw was that Hawking’s calculations were correct,” Steinhauer said. By correct, he means that they’re a real effect that happens in these kinds of systems. Whether they happen in real black holes in space, well, we don’t quite know yet. But they do show that if Hawking was correct, then any information that falls into a black hole is lost, the subject of an important black hole paradox.

Mathematician Silke Weinfurtner at the University of Nottingham in the United Kingdom wrote in a Nature commentary that the research was “promising” and that the scheme the researchers used to extract the temperature of the radiation was “clever.” Perhaps, she wrote, the setup will be useful in measuring other interesting quantum phenomenon expected to occur near the black hole’s event horizon.

This research is yet another example of scientists using analogues to access physical phenomena that might otherwise be impossible to observe. It can serve as an important verification of the theories that drive our understanding of inaccessible things.

Next up, the researchers hope to repeatedly redo the experiment in order to determine how this Hawking radiation changes over time. And who knows, maybe one day we really will be able to measure these properties in actual black holes.

Source: Laboratory Black Hole Shows Stephen Hawking Was Right, Obviously

A mind-controlled hearing aid that allows the wearer to focus on particular voices has been created by scientists, who say it could transform the ability of those with hearing impairments to cope with noisy environments.

The device mimics the brain’s natural ability to single out and amplify one voice against background conversation. Until now, even the most advanced hearing aids work by boosting all voices at once, which can be experienced as a cacophony of sound for the wearer, especially in crowded environments.

Nima Mesgarani, who led the latest advance at Columbia University in New York, said: “The brain area that processes sound is extraordinarily sensitive and powerful. It can amplify one voice over others, seemingly effortlessly, while today’s hearing aids still pale in comparison.”

This can severely hinder a wearer’s ability to join in conversations, making busy social occasions particularly challenging.

[…]

The hearing aid first uses an algorithm to automatically separate the voices of multiple speakers. It then compares these audio tracks to the brain activity of the listener. Previous work by Mesgarani’s lab found that it is possible to identify which person someone is paying attention to, as their brain activity tracks the sound waves of that voice most closely.

The device compares the audio of each speaker to the brain waves of the person wearing the hearing aid. The speaker whose voice pattern most closely matches the listener’s brain waves is amplified over the others, allowing them to effortlessly tune in to that person.

The scientists developed an earlier version of the system in 2017 that, while promising, had the major limitation that it had to be pre-trained to recognise speakers’ voices. Crucially, the latest device works for voices it has never heard before.

[…]

The current version of the hearing aid, which involved direct implants into the brain, would be unsuitable for mainstream use. But the team believe it will be possible to create a non-invasive version of the device within the next five years, which would monitor brain activity using electrodes placed inside the ear, or under the skin of the scalp.

In theory, Mesgarani said, the device could also be used like a pair of audio “binoculars” to covertly listen in on people’s conversations, although this was not the intended application.

Source: Scientists create mind-controlled hearing aid | Society | The Guardian

Uncontrolled bleeding during surgery can cause death. What if, instead of slow surgical stitching, you could rapidly glue a wound together?

A new “bio-glue” — an experimental adhesive gel that is activated by a flash of light — has been proven to stop high pressure bleeding in the hearts of pigs.

Additional research confirming the safety of this product is needed before experiments can begin in humans, according to the authors of a study published Wednesday in the journal Nature Communications.

Around the globe, more than 234 million surgeries are performed each year, the World Health Organization estimates.

Surgical suturing is especially difficult when dealing with diseased, damaged or small blood vessels, according to the study authors. Existing surgical products, such as Fibrin Glue and Surgiflo, have been effective in stopping bleeding during surgeries, but they take minutes to set and in some cases require additional stitching.

Numerous attempts have been made to create improved and swifter-acting surgical adhesives, but few nontoxic materials can meet the criteria of holding fast on wet tissues while resisting pressure and the movement of a beating heart.

A team of researchers from Zhejiang University School of Medicine in Hangzhou, China, accepted the challenge.

Inspired by the matrix composition of human connective tissues, they created a gel composed of a network of proteins and other molecules. The product, which requires ultraviolet light to activate, can adhere within seconds and then bond to wet biological tissue surfaces.

In early experiments, the research team showed that their bio-glue could seal wounds to pig livers.

Next, they demonstrated that wounds and punctures of hearts — among the most difficult of surgical challenges — could also be sealed using only the bio-glue, no stitches.

Source: Bio-glue that moves with a beating heart can repair wounds in pigs – CNN

The lab-made microbe, a strain of bacteria that is normally found in soil and the human gut, is similar to its natural cousins but survives on a smaller set of genetic instructions.

The bug’s existence proves life can exist with a restricted genetic code and paves the way for organisms whose biological machinery is commandeered to make drugs and useful materials, or to add new features such as virus resistance.

In a two-year effort, researchers at the laboratory of molecular biology, at Cambridge University, read and redesigned the DNA of the bacterium Escherichia coli (E coli), before creating cells with a synthetic version of the altered genome.

[…]

The Cambridge team set out to redesign the E coli genome by removing some of its superfluous codons. Working on a computer, the scientists went through the bug’s DNA. Whenever they came across TCG, a codon that makes an amino acid called serine, they rewrote it as AGC, which does the same job. They replaced two more codons in a similar way.

More than 18,000 edits later, the scientists had removed every occurrence of the three codons from the bug’s genome. The redesigned genetic code was then chemically synthesised and, piece by piece, added to E coli where it replaced the organism’s natural genome. The result, reported in Nature, is a microbe with a completely synthetic and radically altered DNA code. Known as Syn61, the bug is a little longer than normal, and grows more slowly, but survives nonetheless.

Source: Cambridge scientists create world’s first living organism with fully redesigned DNA | Science | The Guardian

All matter particles have a corresponding antimatter particle, which shares most of the same properties but is a mirror image of the particle and has the opposite charge. Decades ago, scientists determined that when regular-matter particles pass through a pair of parallel slits, they create an interference pattern as if they were waves. The new experiment from researchers in Italy and Switzerland unsurprisingly affirms that antimatter behaves the same way—but conducting the research required overcoming some difficulties.

The double-slit experiment serves as a foundation for our understanding of matter. Light, when passed through a pair of parallel slits onto a photosensitive detector, reveals a pattern of bright and dark spots. This proves that light travels as a wave; it splits upon hitting the slits, and the waves either cancel each other out or magnify the strength of the signal, creating the pattern. Surprisingly, beams of matter particles like electrons will also form this diffraction pattern, even if you send the electrons one at a time. This demonstrates the probabilistic, dual wave-particle behavior of matter and light that is the foundation of quantum mechanics.

Physicists have already performed diffraction experiments on antimatter that demonstrate its dual wave-particle nature, but this is the first demonstration of a double-slit analog in antimatter, according to the paper published in Science Advances.

Antimatter is rarer than matter, but it exists here on Earth most commonly in the form of positrons, or anti-electrons, produced by certain kinds of radioactive decay. The Laboratory for Nanostructure Epitaxy and Spintronics on Silicon (L-NESS) facility in Italy produces a focused beam of approximately 5,000 positrons per second. The scientists shined the beam through two gold-coated silicon nitride gratings, each with a different distance between the grates. The beam then hit a detector, a 50-micrometer-thick gelatin full of silver bromide crystals, which served as a three-dimensional photographic film.

Upon analyzing the results, the researchers found that the antimatter beam had produced evidence of the expected interference pattern, according to the paper. They concluded that positrons had hit the gratings, interacted with one another as matter waves, and produced the expected interference pattern on the film.

This is only a first step for the QUPLAS (QUantum interferometry with Positrons and LASers) program, which is devoted to performing these interference pattern-based studies on antimatter. They next plan to perform studies on other antimatter particles, like positronium (positrons bound to electrons in an exotic atom) and antihydrogen (an antiproton orbited by a positron). Eventually, they hope to use antimatter to make measurements of Earth’s gravitational field, and to see if other laws of physics hold up when tested on antimatter instead of the regular matter we know and love.

Source: Scientists Recreate Hallmark Quantum Physics Experiment Using Antimatter

Columbia Engineering researchers design new desalination method for hypersaline brines that is low-cost, efficient, and effective; could address the growing water challenges across the globe

About the Study

The study is titled “Membrane-less and Non-evaporative Desalination of Hypersaline Brines by Temperature Swing Solvent Extraction.”

A New Paradigm for Desalination

New York, NY—May 6, 2019—Hypersaline brines—water that contains high concentrations of dissolved salts and whose saline levels are higher than ocean water—are a growing environmental concern around the world. Very challenging and costly to treat, they result from water produced during oil and gas production, inland desalination concentrate, landfill leachate (a major problem for municipal solid waste landfills), flue gas desulfurization in fossil-fuel power plants, and effluent from industrial processes.

If hypersaline brines are improperly managed, they can pollute both surface and groundwater resources. But if there were a simple, inexpensive way to desalinate the brines, vast quantities of water would be available for all kinds of uses, from agriculture to industrial applications, and possibly even for human consumption.

A Columbia Engineering team led by Ngai Yin Yip, assistant professor of earth and environmental engineering, reports today that they have developed a radically different desalination approach—“temperature swing solvent extraction (TSSE)”—for hypersaline brines. The study, published online in Environmental Science & Technology Letters, demonstrates that TSSE can desalinate very high-salinity brines, up to seven times the concentration of seawater. This is a good deal more than reverse osmosis, the gold-standard for seawater desalination, and can handle approximately twice the seawater salt concentrations.

 

Amine solvents (top phase) extracting water from hypersaline brines (bottom phase).

Illustration showing fresh water production from hypersaline brines by temperature swing solvent extraction.

Currently, hypersaline brines are desalinated either by membrane (reverse osmosis) or water evaporation (distillation). Each approach has limitations. Reverse osmosis methods are ineffective for high-saline brines because the pressures applied in reverse osmosis scale with the amount of salt: hypersaline brines require prohibitively high pressurizations. Distillation techniques, which evaporate the brine, are very energy-intensive.

Yip has been working on solvent extraction, a separation method widely employed for chemical engineering processes. The relatively inexpensive, simple, and effective separation technique is used in a wide range of industries, including production of fine organic compounds, purification of natural products, and extraction of valuable metal complexes.

Source: Radical Desalination Approach May Disrupt the Water Industry | Columbia Engineering

Scientists have developed a brain implant that can read people’s minds and turn their thoughts to speech.

[…]

They add that their findings, published in the journal Nature, could help people when disease robs them of their ability to talk.

[…]

The mind-reading technology works in two stages.

First an electrode is implanted in the brain to pick up the electrical signals that manoeuvre the lips, tongue, voice box and jaw.

Then powerful computing is used to simulate how the movements in the mouth and throat would form different sounds.

This results in synthesised speech coming out of a “virtual vocal tract”.

Why do it like that?

You might think it would be easier to scour the brain for the pattern of electrical signals that code for each word.

However, attempts to do so have only had limited success.

Instead it was focusing on the shape of the mouth and the sounds it would produce that allowed the scientists to achieve a world first.

[…]

It is not perfect.

If you listen to this recording of synthesised speech:

You can tell it is not crystal clear (the recording says “the proof you are seeking is not available in books”).

The system is better with prolonged sounds like the “sh” in ship than with abrupt sounds such as the “buh” sound in “books”.

In experiments with five people, who read hundreds of sentences, listeners were able to discern what was being spoken up to 70% of the time when they were given a list of words to choose from.

[…]

The participants in the study were told not to make any specific mouth movements.

Prof Chang said: “There were just asked to do the very simple thing of reading some sentences.

“So it’s a very natural act that the brain translates into movements itself.”

Source: ‘Exhilarating’ implant turns thoughts to speech – BBC News

Rob Wisse, eye doctor at the University Medical Centre of Utrecht used the application on 100 people and compared the results with that of an optometrist. He presented his results at the NOG congres.

Source: ‘Computer kan online bril voorschrijven’ – Emerce