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    Solitonic superfluorescence paves way for high-temperature quantum materials

    A new study in Nature describes both the mechanism and the material conditions necessary for superfluorescence at room temperature. The work could serve as a blueprint for designing materials that allow exotic quantum states — such as superconductivity, superfluidity or superfluorescence — at high temperatures, paving the way for applications such as quantum computers that don’t require extremely low temperatures to operate.
    The international team that did the work was led by North Carolina State University and included researchers from Duke University, Boston University and the Institut Polytechnique de Paris.
    “In this work, we show both experimental and theoretical reasons behind macroscopic quantum coherence at high temperature,” says Kenan Gundogdu, professor of physics at NC State and corresponding author of the study. “In other words, we can finally explain how and why some materials will work better than others in applications that require exotic quantum states at ambient temperatures.”
    Picture a school of fish swimming in unison or the synchronized flashing of fireflies — examples of collective behavior in nature. When similar collective behavior happens in the quantum world — a phenomenon known as macroscopic quantum phase transition — it leads to exotic processes such as superconductivity, superfluidity, or superfluorescence. In all these processes a group of quantum particles forms a macroscopically coherent system that acts like a giant quantum particle.
    However, quantum phase transitions normally require super cold, or cryogenic, conditions to occur. This is because higher temperatures create thermal “noise” that disrupts the synchronization and prevents the phase transition.
    In a previous study, Gundogdu and colleagues had determined that the atomic structure of some hybrid perovskites protected the groups of quantum particles from the thermal noise long enough for the phase transition to occur. In these materials, large polarons — groups of atoms bound to electrons — formed, insulating light emitting dipoles from thermal interference and allowing superfluorescence.
    In the new study, the researchers found out how the insulating effect works. When they used a laser to excite the electrons within the hybrid perovskite they studied, they saw large groups of polarons coming together. This grouping is called a soliton.

    “Picture the atomic lattice as a fine cloth stretched between two points,” Gundogdu says. “If you place solid balls — which represent excitons — on the cloth, each ball deforms the cloth locally. To get an exotic state like superfluorescence you need all the excitons, or balls, to form a coherent group and interact with the lattice as a unit, but at high temperatures thermal noise prevents this.
    “The ball and its local deformation together form a polaron,” Gundogdu continues. “When these polarons transition from a random distribution to an ordered formation in the lattice, they make a soliton, or coherent unit. The soliton formation process dampens the thermal disturbances, which otherwise impede quantum effects.”
    “A soliton only forms when there is enough density of polarons excited in the material,” says Mustafa Türe, NC State Ph.D. student and co-first author of the paper. “Our theory shows that if the density of polarons is low, the system has only free incoherent polarons, whereas beyond a threshold density, polarons evolve into solitons.”
    “In our experiments we directly measured the evolution of a group of polarons from an incoherent uncorrelated phase to an ordered phase,” adds Melike Biliroglu, postdoctoral researcher at NC State and co-first author of the work. “This is one of the first direct observations of macroscopic quantum state formation.”
    To confirm that the soliton formation suppresses the detrimental effects of temperature, the group worked with Volker Blum, the Rooney Family Associate Professor of Mechanical Engineering and Materials Science at Duke, to calculate the lattice oscillations responsible for thermal interference. They also collaborated with Vasily Temnov, professor of physics at CNRS and Ecole Polytechnique, to simulate the recombination dynamics of the soliton in the presence of thermal noise. Their work confirmed the experimental results and verified the intrinsic coherence of the soliton.
    The work represents a leap forward in understanding both how and why certain hybrid perovskites are able to exhibit exotic quantum states.
    “Prior to this work it wasn’t clear if there was a mechanism behind high temperature quantum effects in these materials,” says Franky So, co-author of the paper and the Walter and Ida Freeman Distinguished Professor of Materials Science and Engineering at NC State.
    “This work shows a quantitative theory and backs it up with experimental results,” Gundogdu says. “Macroscopic quantum effects such as superconductivity are key to all the quantum technologies we are pursuing — quantum communication, cryptology, sensing and computation — and all of them are currently limited by the need for low temperatures. But now that we understand the theory, we have guidelines for designing new quantum materials that can function at high temperatures, which is a huge step forward.”
    The work is supported by the Department of Energy, Office of Science (grant no. DE-SC0024396). Researchers Xixi Qin, and Uthpala Herath from Duke University; Anna Swan from Boston University; and Antonia Ghita from the Institut Polytechnique de Paris, also contributed to the work. More

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    New chiral photonic device combines light manipulation with memory

    As fast as modern electronics have become, they could be much faster if their operations were based on light, rather than electricity. Fiber optic cables already transport information at the speed of light; to do computations on that information without translating it back to electric signals will require a host of new optical components.
    Engineering researchers at the University of Utah have now developed such a device — one that can be adjusted on the fly to give light different degrees of circular polarization. Because information can be stored in a property of light known as chirality, the researchers’ device could serve as a multifunctional, reconfigurable component of an optical computing system.
    Led by Weilu Gao, assistant professor in the Department of Electrical & Computer Engineering, and Jichao Fan, a Ph.D. candidate in his lab at the John and Marcia Price College of Engineering, a study demonstrating the device was published in the journal Nature Communications.
    Chiral light refers to electromagnetic waves that exhibit handedness; they can be either left-handed or right-handed. This “handedness” arises from the rotation of the magnetic fields as the light propagates, creating a spiral structure.
    “Traditional chiral optics were like carved stone — beautiful but frozen,” Gao said. “This made them not useful for applications requiring real-time control, like reconfigurable optical computing or adaptive sensors.”
    “We’ve created ‘living’ optical matter that evolves with electrical pulses,” Fan said, “thanks to our aligned-carbon-nanotube-phase-change-material heterostructure that merges light manipulation and memory into a single scalable platform.”
    This “heterostructure” consists of a stack of multiple different thin films, including a collection of aligned carbon nanotubes with different orientations. Other films in the stack consist of germanium-antimony-tellurium, a well-known “phase-change material” or PCM. An electrical pulse along the carbon nanotube layer introduces heat, which in turn causes the PCM layer’s internal structure to transition from amorphous to crystalline.

    “The carbon nanotubes simultaneously act as chiral optical elements and transparent electrodes for PCM switching — eliminating the need for separate control components,” Fan said.
    Critically, this change modifies the heterostructure’s circular dichroism, which means it can be made to absorb different types of circularly polarized light at different strengths. The research team’s advances in manufacturing techniques and artificial-intelligence-assisted design enabled these layers to be assembled into a stacked heterostructure without degrading their individual optical properties.
    Once assembled, the layers selectively reduce the amount of left- or right-circularly polarized light that passes through them, depending on the state of the PCM layer. And because that phase change can be initiated by an electrical pulse, the structure’s overall circular dichroism can be adjusted in real-time.
    The researchers were able to achieve this on the wafer-scale, because of the scalable manufacturing of aligned carbon nanotubes and phase-change-material films.
    Being able to modify the device’s circular dichroism gives researchers fine-grained control over which direction circularly polarized light twists, meaning its “handedness” can be used as memory in an optical circuit. In addition to light’s speed advantage over electricity, there are additional properties of light in which information can be stored in parallel.
    “By adding circular dichroism as an independent parameter, we create an orthogonal information channel,” Gao said. “Adjusting it does not interfere with other properties like amplitude or wavelength.”
    The research was supported by the National Science Foundation through Grants No. 2230727, No. 2235276, No. 2316627 and No. 2321366. More

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    Hitting the right notes to play music by ear

    Learning to play music by ear is challenging for most musicians, but research from a team at the University of Waterloo may help musicians-in-training find the right notes.
    The Waterloo team analyzed a range of YouTube videos that focused on learning music by ear and identified four simple ways music learning technology can better aid prospective musicians — helping people improve recall while listening, limiting playback to small chunks, identifying musical subsequences to memorize, and replaying notes indefinitely.
    “There are a lot of apps and electronic tools out there to help learn by ear from recorded music,” said Christopher Liscio, a recent Waterloo master’s graduate in computer science and the study’s lead author.
    “But we see evidence that musicians don’t appear to use them very much, which makes us question whether these tools are truly well-suited to the task. By studying how people teach and learn how to play music by ear in YouTube videos, we can try to understand what might actually help these ear-learning musicians.”
    The team studied 28 YouTube ear-learning lessons, breaking each down to examine how the instructors structured their teaching and how students would likely retain what they heard. Surprisingly, they found that very few creators or viewers were using existing digital learning tools to loop playback or manipulate playback speed despite their availability for over two decades.
    “We started this research planning to build a specific tool for ear learners, but then we realized we might be reinforcing a negative pattern of building tools without knowing what users actually want,” said Dan Brown, professor of Computer Science at Waterloo. “Then we got excited when we realized YouTube could be a helpful resource for that research process.” More

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    Home water-use app improves water conservation

    A UC Riverside-led study has found that a smartphone app that tracks household water use and alerts users to leaks or excessive consumption offers a promising tool for helping California water agencies meet state-mandated conservation goals.
    Led by Mehdi Nemati, an assistant professor of public policy at UCR, the study found that use of the app — called Dropcountr — reduced average household water use by 6%, with even greater savings among the highest water users.
    Dropcountr works by interpreting water-use data from smart water meters, which many utilities originally installed for remote reading to streamline billing. The app turns data from these meters into real-time feedback for consumers, showing how much water they use, how their usage compares to similar households, and how it has changed over time.
    This type of digital feedback gives users what behavioral economists call a “nudge” — a timely prompt to take water-saving actions, such as taking shorter showers, fixing leaks, or delaying using appliances like dishwashers and washing machines until they are full.
    The app also alerts users when their consumption nears costly higher-rate tiers and notifies them of possible leaks. Utilities also can use the app to send customers tips for cutting use and notify them of rebate programs, such as those for replacing lawns with drought-tolerant landscaping.
    “California water agencies are under pressure to hit individualized water-use targets and conservation goals under the ‘Making Conservation a California Way of Life’ regulation,” Nemati said. “Our study shows that this digital feedback tool can be a powerful, low-cost way to help households manage their use and reduce consumption.”
    The research focused on the City of Folsom in Northern California, where Dropcountr was offered to residential customers beginning in late 2014. About 3,600 households volunteered for the program, which collected smart meter data from 2013 to 2019. This allowed researchers to analyze more than 32 million records of daily water use.

    The findings, published in the journal Resource and Energy Economics, showed that participating households reduced their daily consumption by an average of 6.2% compared to a control group. The reduction was greater among high-volume users. The top 20% of users cut their water use by up to 12%.
    “This is a crucial outcome when every drop counts,” Nemati said. “We found strong, statistically significant reductions, especially for high-use customers.”
    Dropcountr also uses behavioral science concepts, especially the power of social norms. Users receive personalized water-use summaries that show how their consumption stacks up against more efficient nearby households, helping them set reasonable and achievable conservation goals. The app also flags possible leaks by detecting continuous usage patterns — such as when water use remains steady for 72 hours. These alerts were found to be especially effective: Water use dropped roughly 50% on the day after a leak alert was sent, followed by a 30% drop the next day, and a sustained 9% reduction even six days later. “The sharp drop suggests customers are paying attention and acting quickly,” Nemati said. “One major advantage is that they can detect leaks right away — sometimes before they cause damage or result in costly bills. That’s difficult with traditional billing systems, where usage is only seen after 30 or 60 days.” Importantly, the study also found that these behavioral changes lasted. “We looked at water use 50 months out and still found sustained reductions,” Nemati said. “People weren’t just reacting once and forgetting. They stayed engaged.”
    The app works best with homes equipped with smart meters, while many homes in California still rely on older, manually read meters. Fortunately, adoption of advanced metering infrastructure continues to expand.
    Still, Nemati noted, many agencies that do have smart meters continue to rely on outdated methods — like mailed letters — to notify customers of high usage or leaks.
    “People get water bills, but the information may not be salient. Most bills report usage in cubic feet or units, which aren’t easy to interpret,” Nemati said. “What platforms like Dropcountr do well is make the data meaningful. People want to use water wisely. They just need timely, clear, and actionable feedback. These platforms give them that — and they work.”
    With California preparing to enforce stricter drought and efficiency standards, Nemati said more utilities should consider deploying digital tools like Dropcountr.
    “We have the data,” he said. “Now we just need to use it in smarter ways. This study shows how a relatively inexpensive solution can help homeowners conserve and ease pressure on our water systems.”
    The study is titled “High-frequency analytics and residential water consumption: Estimating heterogeneous effects.” Co-authors are Steven Buck of the University of Kentucky and Hilary Soldati of Cal Poly San Luis Obispo. More

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    The magic of light: Dozens of images hidden in a single screen

    From smartphones and TVs to credit cards, technologies that manipulate light are deeply embedded in our daily lives, many of which are based on holography. However, conventional holographic technologies have faced limitations, particularly in displaying multiple images on a single screen and in maintaining high-resolution image quality. Recently, a research team led by Professor Junsuk Rho at POSTECH (Pohang University of Science and Technology) has developed a groundbreaking metasurface technology that can display up to 36 high-resolution images on a surface thinner than a human hair. This research has been published in Advanced Science.
    This achievement is driven by a special nanostructure known as a metasurface. Hundreds of times thinner than a human hair, the metasurface is capable of precisely manipulating light as it passes through. The team fabricated nanometer-scale pillars using silicon nitride, a material known for its robustness and excellent optical transparency. These pillars, referred to as meta-atoms, allow for fine control of light on the metasurface.
    A remarkable aspect of this technology is its ability to project entirely different images depending on both the wavelength (color) and spin (polarization direction) of light. For example, left-circularly polarized red light may reveal an image of an apple, while right-circularly polarized red light may produce an image of a car. Using this technique, the researchers successfully encoded 36 images at 20 nm intervals within the visible spectrum, and 8 images spanning from the visible to the near-infrared region — all onto a single metasurface.
    What makes this innovation particularly notable is not only its simplified design and fabrication process, but also its enhanced image quality. The team addressed previous issues of image crosstalk and background noise by incorporating a noise suppression algorithm, resulting in clearer images with minimal interference between channels.
    “This is the first demonstration of multiplexing spin and wavelength information through a single phase-optimization process while achieving low noise and high image fidelity,” said Professor Rho. “Given its scalability and commercial viability, this technology holds strong potential for a wide range of optical applications, including high-capacity optical data storage, secure encryption systems, and multi-image display technologies.”
    This research was supported by the POSCO Holdings N.EX.T Impact Program, as well as the Pioneer Program for Converging Technology of the National Research Foundation of Korea, funded by the Ministry of Science and ICT. More

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    A chip with natural blood vessels

    How can we investigate the effects of a new drug? How can we better understand the interaction between different organs to grasp the systemic response? In biomedical research, so-called organs-on-a-chip, also referred to as microphysiological systems, are becoming increasingly important: by cultivating tissue structures in precisely controlled microfluidic chips, it is possible to conduct research much more accurately than in experiments involving living humans or animals.
    However, there has been a major obstacle: such mini-organs are incomplete without blood vessels. To facilitate systematic studies and ensure meaningful comparisons with living organisms, a network of perfusable blood vessels and capillaries must be created — in a way that is precisely controllable and reproducible. This is exactly what has now been achieved at TU Wien: the team established a method using ultrashort laser pulses to create tiny blood vessels in a rapid and reproducible manner. Experiments show that these vessels behave just like those in living tissue. Liver lobules have been created on a chip with great success.
    Real Cells in Artificial Microchannels
    “If you want to study how certain drugs are transported, metabolized and absorbed in different human tissues, you need the finest vascular networks,” says Alice Salvadori, a member of the Research Group 3D Printing and Biofabrication established by Prof. Aleksandr Ovsianikov at TU Wien.
    Ideally such blood vessels have to be created directly within special materials called hydrogels. Hydrogels provide structural support for living cells, while being permeable similarly to natural tissues. By creating tiny channels within these hydrogels, it becomes possible to guide the formation of blood vessel-like structures: endothelial cells — the cells that line the inside of real blood vessels in the human body — can settle inside these channel networks. This creates a model that closely mimics the structure and function of natural blood vessels.
    The major challenge so far has been geometry: the shape and size of these microvascular networks have been difficult to control. In self-organization based approaches, vessel geometry varies significantly from one sample to another. This makes it impossible to run reproducible, precisely controlled experiments — yet that is exactly what is needed for reliable biomedical research.
    Improved Hydrogel and Laser Precision
    The team at TU Wien therefore relied on advanced laser technology: with the help of ultrashort laser pulses in the femtosecond range, highly precise3D structures can be written directly into the hydrogel — quickly and efficiently.

    “We can create channels spaced only a hundred micrometers apart. That’s essential when you would like to replicate the natural density of blood vessels in specific organs,” says Aleksandr Ovsianikov.
    But it’s not just about precision: the artificial blood vessels have to be formed quickly and also remain structurally stable once they are populated with living cells. “We know that cells actively remodel their environment. That can lead to deformations or even to the collapse of vessels,” explains Alice Salvadori. “That’s why we also improved the material preparation process.”
    Instead of using the standard single-step gelation method, the team used a two-step thermal curing process: the hydrogel is warmed in two phases, using different temperature, rather than just one. This alters its network structure, producing a more stable material. The vessels formed within such material remain open and maintain their shape over time.
    “We have not only shown that we can produce artificial blood vessels that can actually be perfused. The even more important thing is: We have developed a scalable technology that can be used on an industrial scale,” says Aleksanr Ovsianikov. “It takes only 10 minutes to pattern 30 channels, which is at least 60 times faster than other techniques.”
    Simulating Inflammation: Natural Reactions on a Chip
    If biological processes are to be realistically modeled on a chip, the artificial tissues must behave like their natural counterparts. And this, too, has now been demonstrated:
    “We showed that these artificial blood vessels are colonized by endothelial cells that respond just like real ones in the body,” says Alice Salvadori. “For example, they react to inflammation in the same way — becoming more permeable, just like real blood vessels.”

    This marks an important step toward establishing lab-on-a-chip technology as an industrial standard in many fields of medical research.
    Big Success with Liver Tissue
    “Using this approach, we were able to vascularize a liver model. In collaboration with Keio University (Japan), we developed a liver lobule-on-chip that incorporates a controlled 3D vascular network, closely mimicking the in vivo arrangement of the central vein and sinusoids,” says Aleksandr Ovsianikov.
    “Replicating the liver’s dense and intricate microvasculature has long been a challenge in organ-on-chip research. By building multiple layers of microvessels spanning the entire tissue volume, we were able to ensure adequate nutrient and oxygen supply — which, in turn, led to improved metabolic activity in the liver model. We believe that these advancements bring us a step closer to integrating Organ-on-a-chip technology into preclinical drug discovery,” says Masafumi Watanabe (Keio University).
    “OoC technology and advanced laser technology work well together to create more reliable models of blood vessels and liver tissues. One important breakthrough is the ability to build tiny tissues on a chip that allow liquid to flow through them, similar to how blood flows in the body. This helps researchers better understand how blood flow affects cells. OoC technology also makes it possible to closely observe how cells react under a microscope. These models will help scientists study how the body works and may lead to better treatments and healthcare in the future,” says Prof. Ryo Sudo at Keio University. More

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    Emotional responses crucial to attitudes about self-driving cars

    When it comes to public attitudes toward using self-driving cars, understanding how the vehicles work is important — but so are less obvious characteristics like feelings of excitement or pleasure and a belief in technology’s social benefits.
    Those are key insights of a new study from researchers at Washington State University, who are examining attitudes toward self-driving cars as the technology creeps toward the commercial market — and as questions persist about whether people will readily adopt them.
    The study, published in the journal Transportation Research, surveyed 323 people on their perceptions of autonomous vehicles. Researchers found that considerations such as how much people understand and trust the cars are important in determining whether they would eventually choose to use them.
    “But in addition, we found that some of the non-functional aspects of autonomous vehicles are also very important,” said Wei Peng, an assistant professor in the Edward R. Murrow College of Communication at WSU.
    These included the emotional value associated with using the cars, such as feelings of excitement, enjoyment or novelty; beliefs about the broader impact on society; and curiosity about learning how the technology works and its potential role in the future, Peng said.
    In addition, they found that respondents would want to give the technology a test drive before adopting it.
    “This is not something where you watch the news and say, ‘I want to buy it or I want to use it,'” Peng said. “People want to try it first.”
    The new paper is the latest research on the subject from Peng and doctoral student Kathryn Robinson-Tay. In a paper published in 2023, they examined whether people believed the vehicles were safe, finding that simply knowing more about how the cars work did not improve perceptions about risk — people needed to have more trust in them, too.

    The new study examined the next step in the decision-making chain: What would motivate people to actually use an autonomous vehicle?
    Answering that question is important as the technology moves toward becoming a reality on the roads. Already, carmakers are adding autonomous features to models, and self-driving taxis have begun operating in a handful of U.S, cities, such as Phoenix, San Francisco and Los Angeles. Fully self-driving vehicles could become available by 2035.
    It is estimated they could prevent 90% of accidents while improving mobility for people with limited access to transportation. However, achieving those benefits would require widespread, rapid adoption — a big hurdle given that public attitudes toward the cars have been persistently negative and the rollout of “robotaxies” have been bumpy, with some high-profile accidents and recalls. In a national survey by AAA released in February, 60 percent of respondents said they were afraid to use the cars.
    Widespread adoption would be crucial because roadways shared by self-driving and human-driven cars may not bring about safety improvements, in part because self-drivers may not be able to predict and respond to unpredictable human drivers.
    One surprise in the study is that respondents did not trust vehicles more when they discovered they were easy to use — which opens a new question for future research: “What is it about thinking the car is easy to use that makes people trust it less?” Robinson-Tay asked.
    Attitudes about self-driving cars depend heavily on individual circumstances, and can be nuanced in surprising ways. For example, those with a strong “car-authority identity” — a personal investment in driving and displaying knowledge about automobiles — and more knowledge about self-driving cars were more likely to believe the cars would be easy to use.

    But respondents with more knowledge were less likely to view the cars as useful — a separate variable from ease of use.
    Other considerations also play a role. Those who can’t drive due to disability or other reasons may have a stronger motivation to use them, as might drivers with significant concerns about heavy traffic or driving in inclement weather.
    “If I really worry about snowy weather, like we experience in Pullman in winter, is it going to help?” Peng said. “If I really worry about weather, I might get a car like that if it would help me steer clear of dangerous weather conditions.” More

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    Controlling quantum motion and hyper-entanglement

    Manuel Endres, professor of physics at Caltech, specializes in finely controlling single atoms using devices known as optical tweezers. He and his colleagues use the tweezers, made of laser light, to manipulate individual atoms within an array of atoms to study fundamental properties of quantum systems. Their experiments have led to, among other advances, new techniques for erasing errors in simple quantum machines; a new device that could lead to the world’s most precise clocks; and a record-breaking quantum system controlling more than 6,000 individual atoms.
    One nagging factor in this line of work has been the normal jiggling motion of atoms, which make the systems harder to control. Now, reporting in the journal Science, the team has flipped the problem on its head and used this atomic motion to encode quantum information, a process underlying quantum technologies.
    “We show that atomic motion, which is typically treated as a source of unwanted noise in quantum systems, can be turned into a strength,” says Adam Shaw (PhD ’24), a co-lead author on the study along with Pascal Scholl and Ran Finkelstein. Shaw was formerly a graduate student at Caltech during these experiments and is now a postdoctoral scholar at Stanford University. Scholl served as a postdoc at Caltech and is now working at the quantum computing company Pasqal. Finkelstein held the Troesh Postdoctoral Prize Fellowship at Caltech and is now a professor at Tel Aviv University.
    Ultimately, the experiment not only encoded quantum information in the motion of the atoms but also led to a state known as hyper-entanglement. In basic entanglement, two particles remain connected even when separated by vast distances. When researchers measure the particles’ states, they observe this correlation: For example, if one particle is in a state known as spin up (in which the orientation of the angular momentum is pointing up), the other will always be spin down.
    In hyper-entanglement, two characteristics of a particle pair are correlated. As a simple analogy, this would be like a set of twins separated at birth having both the same names and same types of cars: The two traits are correlated between the twins. In the new study, Endres and his team were able to hyper-entangle pairs of atoms such that their individual states of motion and their individual electronic states — their internal energy levels — were correlated among the atoms. What is more, this experimental demonstration implies that even more traits could be entangled at the same time.
    “This allows us to encode more quantum information per atom,” Endres explains. “You get more entanglement with fewer resources.”
    The experiment is the first demonstration of hyper-entanglement in massive particles, such as neutral atoms or ions (earlier demonstrations used photons).

    For these experiments, the team cooled down an array of individual alkaline-earth neutral atoms confined inside optical tweezers. They demonstrated a novel form of cooling via “detection and subsequent active correction of thermal motional excitations,” says Endres, which he compares to James Clerk Maxwell’s famous 1867 thought experiment invoking a demon that measures and sorts particles in a chamber. “We essentially measure the motion of each atom and apply an operation depending on the outcome, atom-by-atom, similar to Maxwell’s demon.”
    The method, which outperformed the best-known laser cooling techniques, caused the atoms to come to nearly a complete standstill.
    From there, the researchers induced the atoms to oscillate like a swinging pendulum, but with an amplitude of approximately100 nanometers, which is much smaller than the width of a human hair. They were able to excite the atoms into two distinct oscillations simultaneously, causing the motion to be in a state of superposition. Superposition is a quantum state in which a particle exhibits opposite traits simultaneously, like a particle’s spin being both up and down at the same time.
    “You can think of an atom moving in this superposition state like a kid on a swing who starts getting pushed by two parents on opposite sides, but simultaneously,” Endres says. “In our everyday world, this would certainly lead to a parental conflict; in the quantum world, we can remarkably make use of this!”
    They then entangled the individual, swinging atoms to partner atoms, creating a correlated state of motion over several micrometers of distance. After the atoms were entangled, the team then hyper-entangled them in such a way that both the motion and the electronic states of the atoms were correlated.
    “Basically, the goal here was to push the boundaries on how much we could control these atoms,” Endres says. “We are essentially building a toolbox: We knew how to control the electrons within an atom, and we now learned how to control the external motion of the atom as a whole. It’s like an atom toy that you have fully mastered.”
    The findings could lead to new ways to perform quantum computing as well as quantum simulations designed to probe fundamental questions in physics. “Motional states could become a powerful resource for quantum technology, from computing to simulation to precision measurements,” Endres says. More