Computers Math

Physicists have developed a breakthrough concept in quantum encryption that makes private communication more secure over significantly longer distances, surpassing state-of-the-art technologies. For decades, experts believed such a technology upgrade required perfect optical hardware, namely, light sources that strictly emit one light particle (photon) at a time — something extremely difficult and expensive to build. But the new approach uses innovative encryption protocols applied to tiny, engineered materials called quantum dots to send encrypted information securely, even with imperfect light sources. Real-world tests show it can outperform even the best of current systems, potentially bringing quantum-safe communication closer to everyday use.
A team of physicists has made a breakthrough that could bring secure quantum communication closer to everyday use — without needing flawless hardware.
The research, led by PhD students Yuval Bloom and Yoad Ordan, under the guidance of Professor Ronen Rapaport from theRacah Institute of Physics at Hebrew University in collaboration with researchers from Los-Alamos National Labs, and published in PRX Quantum, introduces a new practical approach that significantly improve how we send quantum encrypted information using light particles — even when using imperfect equipment.
Cracking a 40-Year-Old Challenge in Quantum Communication
For four decades, the holy grail of quantum key distribution (QKD) — the science of creating unbreakable encryption using quantum mechanics — has hinged on one elusive requirement: perfectly engineered single-photon sources. These are tiny light sources that can emit one particle of light (photon) at a time. But in practice, building such devices with absolute precision has proven extremely difficult and expensive.
To work around that, the field has relied heavily on lasers, which are easier to produce but not ideal. These lasers send faint pulses of light that contain a small, but unpredictable, number of photons — a compromise that limits both security and the distance over which data can be safely transmitted, as a smart eavesdropper can “steal” the information bits that are encoded simultaneously on more than one photon.
A Better Way with Imperfect Tools
Bloom, Ordan, and their team flipped the script. Instead of waiting for perfect photon sources, they developed two new protocols that work with what we have now — sub-Poissonian photon sources based on quantum dots, which are tiny semiconductor particles that behave like artificial atoms.

By dynamically engineering the optical behavior of these quantum dots and pairing them with nanoantennas, the team was able to tweak how the photons are emitted. This fine-tuning allowed them to suggest and demonstrate two advanced encryption strategies: A truncated decoy state protocol: A new version of a widely used quantum encryption approach, tailored for imperfect single photon sources, that weeds out potential hacking attempts due to multi-photon events. A heralded purification protocol: A new method that dramatically improves signal security by “filtering” the excess photons in real time, ensuring that only true single photon bits are recorded.In simulations and lab experiments, these techniques outperformed even the best versions of traditional laser-based QKD methods — extending the distance over which a secure key can be exchanged by more than 3 decibels, a substantial leap in the field.
A Real-World Test and a Step Toward Practical Quantum Networks
To prove it wasn’t just theory, the team built a real-world quantum communication setup using a room-temperature quantum dot source. They ran their new reinforced version of the well-known BB84 encryption protocol — the backbone of many quantum key distribution systems — and showed that their approach was not only feasible but superior to existing technologies.
What’s more, their approach is compatible with a wide range of quantum light sources, potentially lowering the cost and technical barriers to deploying quantum-secure communication on a large scale.
“This is a significant step toward practical, accessible quantum encryption,” said Professor Rapaport. “It shows that we don’t need perfect hardware to get exceptional performance — we just need to be smarter about how we use what we have.”
Co-Lead author Yuval Bloom added, “We hope this work helps open the door to real-world quantum networks that are both secure and affordable. The cool thing is that we don’t have to wait, it can be implemented with what we already have in many labs world-wide” More

Quantum computers have the potential to solve problems far beyond the reach of today’s fastest supercomputers. But today’s machines are notoriously fragile. The quantum bits, or “qubits,” that store and process information are easily disrupted by their environment, leading to errors that quickly accumulate.
One of the most promising approaches to overcoming this challenge is topological quantum computing, which aims to protect quantum information by encoding it in the geometric properties of exotic particles called anyons. These particles, predicted to exist in certain two-dimensional materials, are expected to be far more resistant to noise and interference than conventional qubits.
“Among the leading candidates for building such a computer are Ising anyons, which are already being intensely investigated in condensed matter labs due to their potential realization in exotic systems like the fractional quantum Hall state and topological superconductors,” said Aaron Lauda, professor of mathematics, physics and astronomy at the USC Dornsife College of Letters, Arts and Sciences and the study’s senior author. “On their own, Ising anyons can’t perform all the operations needed for a general-purpose quantum computer. The computations they support rely on ‘braiding,’ physically moving anyons around one another to carry out quantum logic. For Ising anyons, this braiding only enables a limited set of operations known as Clifford gates, which fall short of the full power required for universal quantum computing.”
But in a new study published in Nature Communications, a team of mathematicians and physicists led by USC researchers has demonstrated a surprising workaround. By adding a single new type of anyon, which was previously discarded in traditional approaches to topological quantum computation, the team shows that Ising anyons can be made universal, capable of performing any quantum computation through braiding alone. The team dubbed these rescued particles “neglectons,” a name that reflects both their overlooked status and their newfound importance. This new anyon emerges naturally from a broader mathematical framework and provides exactly the missing ingredient needed to complete the computational toolkit.
From mathematical trash to quantum treasure
The key lies in a new class of mathematical theories called non-semisimple topological quantum field theories (TQFTs). These extend the standard “semisimple” frameworks that physicists typically use to describe anyons. Traditional models simplify the underlying math by discarding objects with so-called “quantum trace zero,” effectively declaring them useless.
“But those discarded objects turn out to be the missing piece,” Lauda explained. “It’s like finding treasure in what everyone else thought was mathematical garbage.”
The new framework retains these neglected components and reveals a new type of anyon — the neglecton — which, when combined with Ising anyons, allows for universal computation using braiding alone. Crucially, only one neglecton is needed, and it remains stationary while the computation is performed by braiding Ising anyons around it.

A house with unstable rooms
The discovery wasn’t without its mathematical challenges. The non-semisimple framework introduces irregularities that violate unitarity, a fundamental principle ensuring that quantum mechanics preserve probability. Most physicists would have seen this as a fatal flaw.
But Lauda’s team found an elegant workaround. They designed their quantum encoding to isolate these mathematical irregularities away from the actual computation. “Think of it like designing a quantum computer in a house with some unstable rooms,” Lauda explained. “Instead of fixing every room, you ensure all of your computing happens in the structurally sound areas while keeping the problematic spaces off-limits.”
“We’ve effectively quarantined the strange parts of the theory,” Lauda said. “By carefully designing where the quantum information lives, we make sure it stays in the parts of the theory that behave properly, so the computation works even if the global structure is mathematically unusual.”
From pure math to quantum reality
The breakthrough illustrates how abstract mathematics can solve concrete engineering problems in unexpected ways.

“By embracing mathematical structures that were previously considered useless, we unlocked a whole new chapter for quantum information science,” Lauda said.
The research opens new directions both in theory and in practice. Mathematically, the team is working to extend their framework to other parameter values and to clarify the role of unitarity in non-semisimple TQFTs. On the experimental side, they aim to identify specific material platforms where the stationary neglecton could arise and to develop protocols that translate their braiding-based approach into realizable quantum operations.
“What’s particularly exciting is that this work moves us closer to universal quantum computing with particles we already know how to create,” Lauda said. “The math gives a clear target: If experimentalists can find a way to realize this extra stationary anyon, it could unlock the full power of Ising-based systems.”
In addition to Lauda, other authors include the study’s first author, Filippo Iulianelli, and Sung Kim of USC, and Joshua Sussan of Medgar Evers College of The City University of New York.
The study was supported by National Science Foundation (NSF) Grants (DMS-1902092, DMS-2200419, DMS-2401375), Army Research Office (W911NF-20-1-0075), Simons Foundation Collaboration Grant on New Structures in Low-Dimensional Topology, Simons Foundation Travel Support Grant, NSF Graduate Research Fellowship (DGE- 1842487) and PSC CUNY Enhanced Award (66685-00 54). More

Astronomers used a UC Santa Cruz-led AI system to detect a rare supernova, SN 2023zkd, within hours of its explosion, allowing rapid follow-up observations before the fleeting event faded. Evidence suggests the blast was triggered by a massive star’s catastrophic encounter with a black hole companion, either partially swallowing the star or tearing it apart before it could explode on its own. Researchers say the same real-time anomaly-detection AI used here could one day be applied to fields like medical diagnostics, national security, and financial-fraud prevention.The explosion of a massive star locked in a deadly orbit with a black hole has been discovered with the help of artificial intelligence used by an astronomy collaboration led by the University of California, Santa Cruz, that hunts for stars shortly after they explode as supernovae.The blast, named SN 2023zkd, was first discovered in July 2023 with the help of a new AI algorithm designed to scan for unusual explosions in real time. The early alert allowed astronomers to begin follow-up observations immediately — an essential step in capturing the full story of the explosion.
By the time the explosion was over, it had been observed by a large set of telescopes, both on the ground and from space. That included two telescopes at the Haleakalāa Observatory in Hawaiʻi used by the Young Supernova Experiment (YSE) based at UC Santa Cruz.
“Something exactly like this supernova has not been seen before, so it might be very rare,” said Ryan Foley, associate professor of astronomy and astrophysics at UC Santa Cruz. “Humans are reasonably good at finding things that ‘aren’t like the others,’ but the algorithm can flag things earlier than a human may notice. This is critical for these time-sensitive observations.”
Time-bound astrophysics
Foley’s team runs YSE, which surveys an area of the sky equivalent to 6,000 times the full moon (4% of the night sky) every three days and has discovered thousands of new cosmic explosions and other astrophysical transients — dozens of them just days or hours after explosion.

The scientists behind the discovery of SN 2023zkd said the most likely interpretation is that a collision between the massive star and the black hole was inevitable. As energy was lost from the orbit, their separation decreased until the supernova was triggered by the star’s gravitational stress as it was partially swallowed the black hole.
The discovery was published on August 13 in the Astrophysical Journal. “Our analysis shows that the blast was sparked by a catastrophic encounter with a black hole companion, and is the strongest evidence to date that such close interactions can actually detonate a star,” said lead author Alexander Gagliano, a fellow at the NSF Institute for Artificial Intelligence and Fundamental Interactions.
An alternative interpretation considered by the team is that the black hole completely tore the star apart before it could explode on its own. In that case, the black hole quickly pulled in the star’s debris and bright light was generated when the debris crashed into the gas surrounding it. In both cases, a single, heavier black hole is left behind.
An unusual, gradual glow up
Located about 730 million light-years from Earth, SN 2023zkd initially looked like a typical supernova, with a single burst of light. But as the scientists tracked its decline over several months, it did something unexpected: It brightened again. To understand this unusual behavior, the scientists analyzed archival data, which showed something even more unusual: The system had been slowly brightening for more than four years before the explosion. That kind of long-term activity before the explosion is rarely seen in supernovae.
Detailed analysis done in part at UC Santa Cruz revealed that the explosion’s light was shaped by material the star had shed in the years before it died. The early brightening came from the supernova’s blast wave hitting low-density gas. The second, delayed peak was caused by a slower but sustained collision with a thick, disk-like cloud. This structure — and the star’s erratic pre-explosion behavior — suggest that the dying star was under extreme gravitational stress, likely from a nearby, compact companion such as a black hole.

Foley said he and Gagliano had several conversations about the spectra, leading to the eventual interpretation of the binary system with a black hole. Gagliano led the charge in that area, while Foley played the role of “spectroscopy expert” and served as a sounding board — and often, skeptic.
At first, the idea that the black hole triggered the supernova almost sounded like science fiction, Foley recalled. So it was important to make sure all of the observations lined up with this explanation, and Foley said Gagliano methodically demonstrated that they did.
“Our team also built the software platform that we use to consolidate data and manage observations. The AI tools used for this study are integrated into this software ecosystem,” Foley said. “Similarly, our research collaboration brings together the variety of expertise necessary to make these discoveries.”
Co-author Enrico Ramirez-Ruiz, also a professor of astronomy and astrophysics, leads the theory team at UC Santa Cruz. Fellow co-author V. Ashley Villar, an assistant professor of astronomy in the Harvard Faculty of Arts and Sciences, provided AI expertise. The team behind this discovery was led by the Center for Astrophysics | Harvard & Smithsonian and the Massachusetts Institute of Technology as part of YSE.
This work was funded by the National Science Foundation, NASA, the Moore Foundation, and the Packard Foundation. Several students, including Gagliano, are or were NSF graduate research fellows, Foley said.
Societal costs of uncertainty
But currently, Foley said the funding situation and outlook for continued support is very uncertain, forcing the collaboration to take fewer risks, resulting in decreased science output overall. “The uncertainty means we are shrinking,” he said, “reducing the number of students who are admitted to our graduate program — many of them being forced out of the field or to take jobs outside the U.S.”
Although predicting the path this AI approach will take is difficult, Foley said this research is cutting edge. “You can easily imagine similar techniques being used to screen for diseases, focus attention for terrorist attacks, treat mental health issues early, and detect financial fraud,” he explained. “Anywhere real-time detection of anomalies could be useful, these techniques will likely eventually play a role.” More

To build a large-scale quantum computer that works, scientists and engineers need to overcome the spontaneous errors that quantum bits, or qubits, create as they operate.
Scientists encode these building blocks of quantum information to suppress errors in other qubits so that a minority can operate in a way that produces useful outcomes.
As the number of useful (or logical) qubits grows, the number of physical qubits required grows even further. As this scales up, the sheer number of qubits needed to create a useful quantum machine becomes an engineering nightmare.
Now, for the first time, quantum scientists at the Quantum Control Laboratory at the University of Sydney Nano Institute have demonstrated a type of quantum logic gate that drastically reduces the number physical qubits needed for its operation.
To do this, they built an entangling logic gate on a single atom using an error-correcting code nicknamed the ‘Rosetta stone’ of quantum computing. It earns that name because it translates smooth, continuous quantum oscillations into clean, digital-like discrete states, making errors easier to spot and fix, and importantly, allowing a highly compact way to encode logical qubits.
GKP Codes: A Rosetta Stone for Quantum Computing
This curiously named Gottesman-Kitaev-Preskill (GKP) code has for many years offered a theoretical possibility for significantly reducing the physical number of qubits needed to produce a functioning ‘logical qubit’. Albeit by trading efficiency for complexity, making the codes very difficult to control.

Research published on August 21 in Nature Physics demonstrates this as a physical reality, tapping into the natural oscillations of a trapped ion (a charged atom of ytterbium) to store GKP codes and, for the first time, realizing quantum entangling gates between them.
Led by Sydney Horizon Fellow Dr Tingrei Tan at the University of Sydney Nano Institute, scientists have used their exquisite control over the harmonic motion of a trapped ion to bridge the coding complexity of GKP qubits, allowing a demonstration of their entanglement.
“Our experiments have shown the first realization of a universal logical gate set for GKP qubits,” Dr Tan said. “We did this by precisely controlling the natural vibrations, or harmonic oscillations, of a trapped ion in such a way that we can manipulate individual GKP qubits or entangle them as a pair.”
Quantum Logic Gate and Software Innovation
A logic gate is an information switch that allows computers – quantum and classical – to be programmable to perform logical operations. Quantum logic gates use the entanglement of qubits to produce a completely different sort of operational system to that used in classical computing, underpinning the great promise of quantum computers.
First author Vassili Matsos is a PhD student in the School of Physics and Sydney Nano. He said: “Effectively, we store two error-correctable logical qubits in a single trapped ion and demonstrate entanglement between them.

“We did this using quantum control software developed by Q-CTRL, a spin-off start-up company from the Quantum Control Laboratory, with a physics-based model to design quantum gates that minimize the distortion of GKP logical qubits, so they maintain the delicate structure of the GKP code while processing quantum information.”
A Milestone in Quantum Technology
What Mr Matsos did is entangle two ‘quantum vibrations’ of a single atom. The trapped atom vibrates in three dimensions. Movement in each dimension is described by quantum mechanics and each is considered a ‘quantum state’. By entangling two of these quantum states realized as qubits, Mr Matsos created a logic gate using just a single atom, a milestone in quantum technology.
This result massively reduces the quantum hardware required to create these logic gates, which allow quantum machines to be programmed.
Dr Tan said: “GKP error correction codes have long promised a reduction in hardware demands to address the resource overhead challenge for scaling quantum computers. Our experiments achieved a key milestone, demonstrating that these high-quality quantum controls provide a key tool to manipulate more than just one logical qubit.
“By demonstrating universal quantum gates using these qubits, we have a foundation to work towards large-scale quantum-information processing in a highly hardware-efficient fashion.”
Across three experiments described in the paper, Dr Tan’s team used a single ytterbium ion contained in what is known as a Paul trap. This uses a complex array of lasers at room temperature to hold the single atom in the trap, allowing its natural vibrations to be controlled and utilized to produce the complex GKP codes.
This research represents an important demonstration that quantum logic gates can be developed with a reduced physical number of qubits, increasing their efficiency.
The authors declare no competing interests. Funding was received from the Australian Research Council, Sydney Horizon Fellowship, the US Office of Naval Research, the US Army Research Office, the US Air Force Office of Scientific Research, Lockheed Martin, Sydney Quantum Academy and private funding from H. and A. Harley. More

The entry of quantum computers into society is currently hindered by their sensitivity to disturbances in the environment. Researchers from Chalmers University of Technology in Sweden, and Aalto University and the University of Helsinki in Finland, now present a new type of exotic quantum material, and a method that uses magnetism to create stability. This breakthrough can make quantum computers significantly more resilient – paving the way for them to be robust enough to tackle quantum calculations in practice.
At the atomic scale, the laws of physics deviate from those in our ordinary large-scale world. There, particles adhere to the laws of quantum physics, which means they can exist in multiple states simultaneously and influence each other in ways that are not possible within classical physics. These peculiar but powerful phenomena hold the key to quantum computing and quantum computers, which have the potential to solve problems that no conventional supercomputer can handle today.
But before quantum calculations can benefit society in practice, physicists need to solve a major challenge. Qubits, the basic units of a quantum computer, are extremely delicate. The slightest change in temperature, magnetic field, or even microscopic vibrations causes the qubits to lose their quantum states – and thus also their ability to perform complex calculations reliably.
To solve the problem, researchers in recent years have begun exploring the possibility of creating materials that can provide better protection against these types of disturbances and noise in their fundamental structure – their topology. Quantum states that arise and are maintained through the structure of the material used in qubits are called topological excitations and are significantly more stable and resilient than others. However, the challenge remains to find materials that naturally support such robust quantum states.
Newly developed material protects against disturbances
Now, a research team from Chalmers University of Technology, Aalto University, and the University of Helsinki has developed a new quantum material for qubits that exhibits robust topological excitations. The breakthrough is an important step towards realising practical topological quantum computing by constructing stability directly into the material’s design.
“This is a completely new type of exotic quantum material that can maintain its quantum properties when exposed to external disturbances. It can contribute to the development of quantum computers robust enough to tackle quantum calculations in practice,” says Guangze Chen, postdoctoral researcher in applied quantum physics at Chalmers and lead author of the study published in Physical Review Letters.

‘Exotic quantum materials’ is an umbrella term for several novel classes of solids with extreme quantum properties. The search for such materials, with special resilient properties, has been a long-standing challenge.
Magnetism is the key in the new strategy
Traditionally, researchers have followed a well-established ‘recipe’ based on spin-orbit coupling, a quantum interaction that links the electron’s spin to its movement orbit around the atomic nucleus to create topological excitations. However, this ‘ingredient’ is relatively rare, and the method can therefore only be used on a limited number of materials.
In the study, the research team presents a completely new method that uses magnetism – a much more common and accessible ingredient – to achieve the same effect. By harnessing magnetic interactions, the researchers were able to engineer the robust topological excitations required for topological quantum computing.
“The advantage of our method is that magnetism exists naturally in many materials. You can compare it to baking with everyday ingredients rather than using rare spices,” explains Guangze Chen. “This means that we can now search for topological properties in a much broader spectrum of materials, including those that have previously been overlooked.”
Paving the way for next-generation quantum computer platforms
To accelerate the discovery of new materials with useful topological properties, the research team has also developed a new computational tool. The tool can directly calculate how strongly a material exhibits topological behaviour.
“Our hope is that this approach can help guide the discovery of many more exotic materials,” says Guangze Chen. “Ultimately, this can lead to next-generation quantum computer platforms, built on materials that are naturally resistant to the kind of disturbances that plague current systems.” More

Cornell University researchers have developed a low-power microchip they call a “microwave brain,” the first processor to compute on both ultrafast data signals and wireless communication signals by harnessing the physics of microwaves.
Detailed today in the journal Nature Electronics, the processor is the first, true microwave neural network and is fully integrated on a silicon microchip. It performs real-time frequency domain computation for tasks like radio signal decoding, radar target tracking and digital data processing, all while consuming less than 200 milliwatts of power.
“Because it’s able to distort in a programmable way across a wide band of frequencies instantaneously, it can be repurposed for several computing tasks,” said lead author Bal Govind, a doctoral student who conducted the research with Maxwell Anderson, also a doctoral student. “It bypasses a large number of signal processing steps that digital computers normally have to do.”
That capability is enabled by the chip’s design as a neural network, a computer system modeled on the brain, using interconnected modes produced in tunable waveguides. This allows it to recognize patterns and learn from data. But unlike traditional neural networks that rely on digital operations and step-by-step instructions timed by a clock, this network uses analog, nonlinear behavior in the microwave regime, allowing it to handle data streams in the tens of gigahertz – much faster than most digital chips.
“Bal threw away a lot of conventional circuit design to achieve this,” said Alyssa Apsel, professor of engineering, who was co-senior author with Peter McMahon, associate professor of applied and engineering physics. “Instead of trying to mimic the structure of digital neural networks exactly, he created something that looks more like a controlled mush of frequency behaviors that can ultimately give you high-performance computation.”
The chip can perform both low-level logic functions and complex tasks like identifying bit sequences or counting binary values in high-speed data. It achieved at or above 88% accuracy on multiple classification tasks involving wireless signal types, comparable to digital neural networks but with a fraction of the power and size.
“In traditional digital systems, as tasks get more complex, you need more circuitry, more power and more error correction to maintain accuracy,” Govind said. “But with our probabilistic approach, we’re able to maintain high accuracy on both simple and complex computations, without that added overhead.”
The chip’s extreme sensitivity to inputs makes it well-suited for hardware security applications like sensing anomalies in wireless communications across multiple bands of microwave frequencies, according to the researchers.

“We also think that if we reduce the power consumption more, we can deploy it to applications like edge computing,” Apsel said, “You could deploy it on a smartwatch or a cellphone and build native models on your smart device instead of having to depend on a cloud server for everything.”
Though the chip is still experimental, the researchers are optimistic about its scalability. They are experimenting with ways to improve its accuracy and integrate it into existing microwave and digital processing platforms.
The work emerged from an exploratory effort within a larger project supported by the Defense Advanced Research Projects Agency and the Cornell NanoScale Science and Technology Facility, which is funded in part by the National Science Foundation. More

A public-private partnership between Commonwealth Fusion Systems (CFS), the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) and Oak Ridge National Laboratory has led to a new artificial intelligence (AI) approach that is faster at finding what’s known as “magnetic shadows” in a fusion vessel: safe havens protected from the intense heat of the plasma.
Known as HEAT-ML, the new AI could lay the foundation for software that significantly speeds up the design of future fusion systems. Such software could also enable good decision-making during fusion operations by adjusting the plasma so that potential problems are thwarted before they start.
“This research shows that you can take an existing code and create an AI surrogate that will speed up your ability to get useful answers, and it opens up interesting avenues in terms of control and scenario planning,” said Michael Churchill, co-author of a paper in Fusion Engineering and Design about HEAT-ML and head of digital engineering at PPPL.
Fusion, the reaction that fuels the sun and stars, could provide potentially limitless amounts of electricity on Earth. To harness it, researchers need to overcome key scientific and engineering challenges. One such challenge is handling the intense heat coming from the plasma, which reaches temperatures hotter than the sun’s core when confined using magnetic fields in a fusion vessel known as a tokamak. Speeding up the calculations that predict where this heat will hit and what parts of the tokamak will be safe in the shadows of other parts is key to bringing fusion power to the grid.
“The plasma-facing components of the tokamak might come in contact with the plasma, which is very hot and can melt or damage these elements,” said Doménica Corona Rivera, an associate research physicist at PPPL and first author on the paper on HEAT-ML. “The worst thing that can happen is that you would have to stop operations.”
PPPL amplifies its impact through public-private partnership
HEAT-ML was specifically made to simulate a small part of SPARC: a tokamak currently under construction by CFS. The Massachusetts company hopes to demonstrate net energy gain by 2027, meaning SPARC would generate more energy than it consumes.

Simulating how heat impacts SPARC’s interior is central to this goal and a big computing challenge. To break down the challenge into something manageable, the team focused on a section of SPARC where the most intense plasma heat exhaust intersects with the material wall. This particular part of the tokamak, representing 15 tiles near the bottom of the machine, is the part of the machine’s exhaust system that will be subjected to the most heat.
To create such a simulation, researchers generate what they call shadow masks. Shadow masks are 3D maps of magnetic shadows, which are specific areas on the surfaces of a fusion system’s internal components that are shielded from direct heat. The location of these shadows depends on the shape of the parts inside the tokamak and how they interact with the magnetic field lines that confine the plasma.
Creating simulations to optimize the way fusion systems operate
Originally, an open-source computer program called HEAT, or the Heat flux Engineering Analysis Toolkit, calculated these shadow masks. HEAT was created by CFS Manager Tom Looby during his doctoral work with Matt Reinke, now leader of the SPARC Diagnostic Team, and was first applied on the exhaust system for PPPL’s National Spherical Torus Experiment-Upgrade machine.
HEAT-ML traces magnetic field lines from the surface of a component to see if the line intersects other internal parts of the tokamak. If it does, that region is marked as “shadowed.” However, tracing these lines and finding where they intersect the detailed 3D machine geometry was a significant bottleneck in the process. It could take around 30 minutes for a single simulation and even longer for some complex geometries.
HEAT-ML overcomes this bottleneck, accelerating the calculations to a few milliseconds. It uses a deep neural network: a type of AI that has hidden layers of mathematical operations and parameters that it applies to the data to learn how to do a specific task by looking for patterns. HEAT-ML’s deep neural network was trained using a database of approximately 1,000 SPARC simulations from HEAT to learn how to calculate shadow masks.
HEAT-ML is currently tied to the specific design of SPARC’s exhaust system; it only works for that small part of that particular tokamak and is an optional setting in the HEAT code. However, the research team hopes to expand its capabilities to generalize the calculation of shadow masks for exhaust systems of any shape and size, as well as the rest of the plasma-facing components inside a tokamak.
DOE supported this work under contracts DE-AC02-09CH11466 and DE-AC05-00OR22725, and it also received support from CFS. More

Animals like bats, whales and insects have long used acoustic signals for communication and navigation. Now, an international team of scientists have taken a page from nature’s playbook to model micro-sized robots that use sound waves to coordinate into large swarms that exhibit intelligent-like behavior. The robot groups could one day carry out complex tasks like exploring disaster zones, cleaning up pollution, or performing medical treatments from inside the body, according to team lead Igor Aronson, Huck Chair Professor of Biomedical Engineering, Chemistry, and Mathematics at Penn State.
“Picture swarms of bees or midges,” Aronson said. “They move, that creates sound, and the sound keeps them cohesive, many individuals acting as one.”
The researchers published their work on August 12 in the journal Physical Review X.
Since the miniature, sound-broadcasting swarms of micromachines are self-organizing, they can navigate tight spaces and even re-form themselves if deformed. The swarms’ collective — or emergent — intelligence could one day be harnessed to carry out tasks like cleaning up pollution in contaminated environments, Aronson explained.
Beyond the environment, the robot swarms could potentially work inside the body, delivering drugs directly to a problem area, for example. Their collective sensing also helps in detecting changes in surroundings, and their ability to “self-heal” means they can keep functioning as a collective unit even after breaking apart, which could be especially useful for threat detection and sensor applications, Aronson said.
“This represents a significant leap toward creating smarter, more resilient and, ultimately, more useful microrobots with minimal complexity that could tackle some of our world’s toughest problems,” he said. “The insights from this research are crucial for designing the next generation of microrobots, capable of performing complex tasks and responding to external cues in challenging environments.”
For the study, the team developed a computer model to track the movements of tiny robots, each equipped with an acoustic emitter and a detector. They found that acoustic communication allowed the individual robotic agents to work together seamlessly, adapting their shape and behavior to their environment, much like a school of fish or a flock of birds.

While the robots in the paper were computational agents within a theoretical — or agent-based — model, rather than physical devices that were manufactured, the simulations observed the emergence of collective intelligence that would likely appear in any experimental study with the same design, Aronson said.
“We never expected our models to show such a high level of cohesion and intelligence from such simple robots,” Aronson said. “These are very simple electronic circuits. Each robot can move along in some direction, has a motor, a tiny microphone, speaker and an oscillator. That’s it, but nonetheless it’s capable of collective intelligence. It synchronizes its own oscillator to the frequency of the swarm’s acoustic field and migrates toward the strongest signal.”
The discovery marks a new milestone for a budding field called active matter, the study of the collective behavior of self-propelled microscopic biological and synthetic agents, from swarms of bacteria or living cells to microrobots. It shows for the first time that sound waves can function as a means of controlling the micro-sized robots, Aronson explained. Up until now, active matter particles have been controlled predominantly through chemical signaling.
“Acoustic waves work much better for communication than chemical signaling,” Aronson said. “Sound waves propagate faster and farther almost without loss of energy — and the design is much simpler. The robots effectively ‘hear’ and ‘find’ each other, leading to collective self-organization. Each element is very simple. The collective intelligence and functionality arise from minimal ingredients and simple acoustic communication.”
The other authors on the paper are Alexander Ziepke, Ivan Maryshev and Erwin Frey of the Ludwig Maximilian University of Munich. The John Templeton Foundation funded the research. More