Computers Math

Someday, scientists believe, tiny DNA-based robots and other nanodevices will deliver medicine inside our bodies, detect the presence of deadly pathogens, and help manufacture increasingly smaller electronics.
Researchers took a big step toward that future by developing a new tool that can design much more complex DNA robots and nanodevices than were ever possible before in a fraction of the time.
In a paper published today (April 19, 2021) in the journal Nature Materials, researchers from The Ohio State University — led by former engineering doctoral student Chao-Min Huang — unveiled new software they call MagicDNA.
The software helps researchers design ways to take tiny strands of DNA and combine them into complex structures with parts like rotors and hinges that can move and complete a variety of tasks, including drug delivery.
Researchers have been doing this for a number of years with slower tools with tedious manual steps, said Carlos Castro, co-author of the study and associate professor of mechanical and aerospace engineering at Ohio State.
“But now, nanodevices that may have taken us several days to design before now take us just a few minutes,” Castro said. More

A new study outlines the need for materials advances in the hardware that goes into making quantum computers if these futuristic devices are to surpass the abilities of the computers we use today.
The study, published in the journal Science by an international team, surveyed the state of research on quantum computing hardware with the goal of illustrating the challenges and opportunities facing scientists and engineers.
While conventional computers encode “bits” of information as ones and zeroes, quantum computers breeze past this binary arrangement by creating “qubits,” which can be complex, continuous quantities. Storing and manipulating information in this exotic form — and ultimately reaching “quantum advantage” where quantum computers do things that conventional computers cannot — requires sophisticated control of the underlying materials.
“There has been an explosion in developing quantum technologies over the last 20 years,” said Nathalie de Leon, assistant professor of electrical and computer engineering at Princeton University and the lead author of the paper, “culminating in current efforts to show quantum advantage for a variety of tasks, from computing and simulation to networking and sensing.”
Until recently, most of this work has aimed to demonstrate proof-of-principle quantum devices and processors, de Leon said, but now the field is poised to address real-world challenges.
“Just as classical computing hardware became an enormous field in materials science and engineering in the last century, I think the quantum technologies field is now ripe for a new approach, where materials scientists, chemists, device engineers and other scientists and engineers can productively bring their expertise to bear on the problem.”
The paper is a call to scientists who study materials to turn to the challenge of developing hardware for quantum computing, said Hanhee Paik, corresponding author and a research staff member at IBM Quantum. More

The internet seems like the place to go to get into fights. Whether they’re with a family member or a complete stranger, these arguments have the potential to destroy important relationships and consume a lot of emotional energy.
Researchers at the University of Washington worked with almost 260 people to understand these disagreements and to develop potential design interventions that could make these discussions more productive and centered around relationship-building. The team published these findings this April in the latest issue of the Proceedings of the ACM in Human Computer Interaction Computer-Supported Cooperative Work.
“Despite the fact that online spaces are often described as toxic and polarizing, what stood out to me is that people, surprisingly, want to have difficult conversations online,” said lead author Amanda Baughan, a UW doctoral student in the Paul G. Allen School of Computer Science & Engineering. “It was really interesting to see that people are not having the conversations they want to have on online platforms. It pointed to a big opportunity to design to support more constructive online conflict.”
In general, the team said, technology has a way of driving users’ behaviors, such as logging onto apps at odd times to avoid people or deleting enjoyable apps to avoid spending too much time on them. The researchers were interested in the opposite: how to make technology respond to people’s behaviors and desires, such as to strengthen relationships or have productive discussions.
“Currently many of the designed features that users leverage during an argument support a no-road-back approach to disagreement — if you don’t like someone’s content, you can unfollow, unfriend or block them. All of those things cut off relationships instead of helping people repair them or find common ground,” said senior author Alexis Hiniker, an assistant professor in the UW Information School. “So we were really driven by the question of how do we help people have hard conversations online without destroying their relationships?”
The researchers did their study in three parts. First, they interviewed 22 adults from the Seattle area about what social media platforms they used and whether they felt like they could talk about challenging topics. The team also asked participants to brainstorm potential ways that these platforms could help people have more productive conversations. More

Gas accidents such as toxic gas leakage in factories, carbon monoxide leakage of boilers, or toxic gas suffocation during manhole cleaning continue to claim lives and cause injuries. Developing a sensor that can quickly detect toxic gases or biochemicals is still an important issue in public health, environmental monitoring, and military sectors. Recently, a research team at POSTECH has developed an inexpensive, ultra-compact wearable hologram sensor that immediately notifies the user of volatile gas detection.
A joint research team led by Professor Junsuk Rho of departments of mechanical and chemical engineering and Dr. Inki Kim of Department of Mechanical Engineering with Professor Young-Ki Kim and Ph.D. candidate Won-Sik Kim of Department of Chemical Engineering at POSTECH has integrated metasurface with gas-reactive liquid crystal optical modulator to develop a sensor that provides an immediate visual holographic alarm when harmful gases are detected. The findings from this study were published in Science Advances on April 7, 2021.
For those working in hazardous environments such as petrochemical plants, gas sensors are life. However, conventional gas sensing devices are not widely used due to their high cost of being made with complex machines and electronic devices. In addition, commercial gas sensors have limitations in that they are difficult to use, and have poor portability and reaction speed.
To solve these issues, the research team utilized the metasurface, well known as a future optical device known to have the invisible cloak effect through making visible objects disappear by controlling the refractive index of light. Metasurface is especially used to transmit two-way holograms or 3D video images by freely controlling light.
Using the metasurface, the research team developed a gas sensor that can float a holographic image alarm in space in just a few seconds by using the polarization control of transmitted light that transforms due to the change in orientation of liquid crystal molecules in the liquid crystal layer inside the sensor device when exposed to gas. Moreover, this gas sensor developed by the research team requires no support from external mechanical or electronic devices, unlike other conventional commercial gas sensors. The researchers used isopropyl alcohol as the target hazardous gas, known as a toxic substance that can cause stomach pain, headache, dizziness, and even leukemia.
The newly developed sensor was confirmed to detect even the minute amount of gas of about 200ppm. In an actual experiment using a board marker, a volatile gas source in our daily life, a visual holographic alarm popped up instantaneously the moment the marker was brought to the sensor.
Moreover, the research team developed a one-step nanocomposite printing method to produce this flexible and wearable gas sensor. The metasurface structure, which was previously processed on a hard substrate, was designed to enable rapid production with a single-step nanocasting process on a curved or flexible substrate.
When the flexible sensor fabricated using this method attaches like a sticker on safety glasses, it can detect gas and display a hologram alarm. It is anticipated to be integrable with glass-type AR display systems under development at Apple, Samsung, Google, and Facebook.
Going a step further, the research team is developing a high-performance environmental sensor that can display the type and concentration level of gases or biochemicals in the surroundings with a holographic alarm, and is studying optical design techniques that can encode various holographic images. If these studies are successful, they can be used to reduce accidents caused by biochemical or gas leaks.
“This newly developed ultra-compact wearable gas sensor provides a more intuitive holographic visual alarm than the conventional auditory or simple light alarms,” remarked Prof. Junsuk Rho. “It is anticipated to be especially effective in more extreme work environments where acoustic and visual noise are intense.” More

When temperatures drop below zero degrees Celsius, water turns to ice. But does everything actually freeze if you just cool it down enough? In the classical picture, matter inherently becomes solid at low temperatures. Quantum mechanics can, however, break this rule. Therefore, helium gas, for example, can become liquid at -270 degrees, but never solid under atmospheric pressure: There is no helium ice.
The same is true for the magnetic properties of materials: at sufficiently low temperatures, the magnetic moments known as ‘spins’, for example, arrange themselves in such a way that they are oriented opposite/antiparallel to their respective neighbors. One can think of this as arrows pointing alternating up and down along a chain or in a checkerboard pattern. It gets frustrating when the pattern is based on triangles: While two spins can align in opposite directions, the third is always parallel to one of them and not to the other — no matter how you turn it.
For this problem, quantum mechanics suggests the solution that the orientation and bond of two spins are not rigid, but the spins fluctuate. The state formed is called a quantum spin liquid in which the spins constitute a quantum mechanically entangled ensemble. This idea was proposed almost fifty years ago by the American Nobel laureate Phil W. Anderson (1923-2020). After decades of research, only a handful of real materials remain in the search for this exotic state of matter. As a particularly promising “candidate” a triangular lattice in a complex organic compound was considered, in which no magnetic order with a regular up-down pattern could be observed, even at extremely low temperatures. Was this the proof that quantum spin liquids really exist?
One problem is that it is extremely challenging to measure electron spins down to such extremely low temperatures, especially along different crystal directions and in variable magnetic fields. All previous experiments have been able to probe quantum spin liquids only more or less indirectly, and their interpretation is based on certain assumptions and models. Therefore, a new method of broadband electron spin resonance spectroscopy has been developed over many years at the Institute of Physics 1 at the University of Stuttgart.
Using on-chip microwave lines, one can directly observe the properties of the spins down to a few hundredths of a degree above absolute zero. In doing so, the researchers found that the magnetic moments do not arrange themselves in the up-down pattern of a typical magnet, nor do they form a dynamic state resembling a liquid. “In fact, we observed the spins in spatially separated pairs. Thus, our experiments have shattered the dream of a quantum spin liquid for now, at least for this compound,” summarizes Prof. Martin Dressel, head of the Institute of Physics 1.
But even though the pairs did not fluctuate as hoped, this exotic ground state of matter has lost none of its fascination for the physicists. “We want to investigate whether quantum spin liquids might be detectable in other triangular lattice compounds or even in completely different systems such as honeycomb structures,” Dressel outlines the next steps. However, it could also be that such a disordered, dynamic state simply does not exist in nature. Perhaps every kind of interaction leads in one way or another to a regular arrangement if the temperature is low enough. Spins just like to pair up.
Story Source:
Materials provided by Universitaet Stuttgart. Note: Content may be edited for style and length. More

A team of researchers from QuTech in the Netherlands reports realization of the first multi-node quantum network, connecting three quantum processors. In addition, they achieved a proof-of-principle demonstration of key quantum network protocols. Their findings mark an important milestone towards the future quantum internet and have now been published in Science.
The quantum internet
The power of the Internet is that it allows any two computers on Earth to be connected with each other, enabling applications undreamt of at the time of its creation decades ago. Today, researchers in many labs around the world are working towards first versions of a quantum internet — a network that can connect any two quantum devices, such as quantum computers or sensors, over large distances. Whereas today’s Internet distributes information in bits (that can be either 0 or 1), a future quantum internet will make use of quantum bits that can be 0 and 1 at the same time. ‘A quantum internet will open up a range of novel applications, from unhackable communication and cloud computing with complete user privacy to high-precision time-keeping,’ says Matteo Pompili, PhD student and a member of the research team. ‘And like with the Internet 40 years ago, there are probably many applications we cannot foresee right now.’
Towards ubiquitous connectivity
The first steps towards a quantum internet were taken in the past decade by linking two quantum devices that shared a direct physical link. However, being able to pass on quantum information through intermediate nodes (analogous to routers in the classical internet) is essential for creating a scalable quantum network. In addition, many promising quantum internet applications rely on entangled quantum bits, to be distributed between multiple nodes. Entanglement is a phenomenon observed at the quantum scale, fundamentally connecting particles at small and even at large distances. It provides quantum computers their enormous computational power and it is the fundamental resource for sharing quantum information over the future quantum internet. By realizing their quantum network in the lab, a team of researchers at QuTech — a collaboration between Delft University of Technology and TNO — is the first to have connected two quantum processors through an intermediate node and to have established shared entanglement between multiple stand-alone quantum processors.
Operating the quantum network
The rudimentary quantum network consists of three quantum nodes, at some distance within the same building. To make these nodes operate as a true network, the researchers had to invent a novel architecture that enables scaling beyond a single link. The middle node (called Bob) has a physical connection to both outer nodes (called Alice and Charlie), allowing entanglement links with each of these nodes to be established. Bob is equipped with an additional quantum bit that can be used as memory, allowing a previously generated quantum link to be stored while a new link is being established. After establishing the quantum links Alice-Bob and Bob-Charlie, a set of quantum operations at Bob converts these links into a quantum link Alice-Charlie. Alternatively, by performing a different set of quantum operations at Bob, entanglement between all three nodes is established. More

Inspired by the workings of a bat’s ear, Rolf Mueller, a professor of mechanical engineering at Virginia Tech, has created bio-inspired technology that determines the location of a sound’s origin.
Mueller’s development works from a simpler and more accurate model of sound location than previous approaches, which have traditionally been modeled after the human ear. His work marks the first new insight for determining sound location in 50 years.
The findings were published in Nature Machine Intelligence by Mueller and a former Ph.D. student, lead author Xiaoyan Yin.
“I have long admired bats for their uncanny ability to navigate complex natural environments based on ultrasound and suspected that the unusual mobility of the animal’s ears might have something to do with this,” said Mueller.
A new model for sound location
Bats navigate as they fly by using echolocation, determining how close an object is by continuously emitting sounds and listening to the echoes. Ultrasonic calls are emitted from the bat’s mouth or nose, bouncing off the elements of its environment and returning as an echo. They also gain information from ambient sounds. Comparing sounds to determine their origin is called the Doppler effect. More

In 2018, when Professor Laurie Santos introduced her course “Psychology and the Good Life,” a class on the science of happiness, it became the most popular in the history of Yale, attracting more than 1,200 undergraduate enrollees that first semester. An online course based on those teachings became a global phenomenon. By latest count, 3.38 million people have enrolled to take the free Coursera.org course, called “The Science of Well Being.”
But the popularity of the course posed an interesting question. Does taking the course and participating in homework assignments — which include nurturing social connections, compiling a gratitude list, and meditation — really help improve a sense of well-being?
The answer is yes, according to two new studies that measured the psychological impact on individuals who took Santos’s or a similar course. The findings suggest that free online courses that teach principles of positive psychology can enrich the lives of millions of people.
In the latest study, published April 14 in the journal PLOS ONE, researchers at Johns Hopkins University and Yale found that people who took the online “Science of Well Being” course reported a greater sense of well-being than those enrolled in another Yale Coursera course, “Introduction to Psychology.” Although learners in both classes said they experienced significant improvement in their well-being after taking the courses, those who took the “Science of Well-Being” course reported greater mental health benefits than those learning about the basics of psychology.
Unlike the psychology course, “The Science of Well Being” requires participants to do exercises known to improve psychological health, such as improving sleep patterns, developing exercise routines, and practicing meditation, the authors say. Before and after taking the course, participants answered questions designed to measure factors related to psychological health such as positive emotions, engagement, and strength of relationships.
“Knowledge is great but it isn’t enough. You also have to do the work,” said lead author David Yaden, research fellow in the Department of Psychiatry and Behavioral Sciences at Johns Hopkins.
A similar study in Health Psychology Open, conducted by researchers at Yale and the University of Bristol, surveyed people who took either a live or an online credit-bearing course based on Santos’s original class and found similar psychological benefits for enrollees.
Yaden stressed, however, that the classes are not a substitute for professional treatment for those who suffer from diagnosed mental illness. “These courses are not a panacea or replacement for psychotherapy or medication,” he said.
However, both Yaden and Santos, who co-authored the study, say the findings show that massive open online courses can provide at least modest value to millions of people at no cost.
“We wanted to know if we could scale these benefits and we can,” Santos said. “Even bringing a small mental health benefit to millions of people can have a huge value.”
Other authors of the PLOS ONE paper are Jennifer Claydon,, Meghan Bathgate, and Belinda Platt of the Yale Poorvu Center for Teaching and Learning.
Story Source:
Materials provided by Yale University. Original written by Bill Hathaway. Note: Content may be edited for style and length. More