To the point:

• Bridging mathematics and physics: The study explores how algebraic and one of the key players in the flourishing field of positive geometry unify physics from subatomic particles to galaxies.
• Beyond Feynman diagrams: Positive geometry offers a complementary perspective to traditional quantum field theory methods — providing a geometric framework for describing particle interactions alongside Feynman diagrams.
• From particle collisions to the Big Bang: Tools from algebraic geometry, D-module theory, and combinatorics drive this interdisciplinary progress — helping to decode the fundamental structures of particle interactions and the universe’s earliest states.

Mathematics and physics share a close, reciprocal relationship. Mathematics offers the language and tools to describe physical phenomena, while physics drives the development of new mathematical ideas. This interplay remains vital in areas such as quantum field theory and cosmology, where advanced mathematical structures and physical theory evolve together.

In their article, the authors explore how algebraic structures and geometric shapes can help us understand phenomena ranging from particle collisions such as happens, for instance, in particle accelerators to the large-scale architecture of the cosmos. Their research is centered around algebraic geometry. Their recent undertakings also connect to a field called positive geometry – an interdisciplinary and novel subject in mathematics driven by new ideas in particle physics and cosmology. This field was inspired by the geometrical concept of positive geometry which expands the standard Feynman diagram approach in particle physics by representing interactions as volumes of high-dimensional geometric objects, such as the amplituhedron, as introduced by the theoretical physicists Nima Arkani-Hamed and Jaroslav Trnka in 2013. It carries a rich combinatorial structure and offers an alternative, potentially simpler way to compute scattering amplitudes, from which one can derive probabilities of scattering events.

This approach has far-reaching implications that go beyond particle physics. In cosmology, scientists are using the faint light of the cosmic microwave background and the distribution of galaxies to infer what shaped the early universe. Similar mathematical tools are now being applied. For instance, cosmological polytopes, which are themselves positive geometries, can represent correlations in the universe’s first light and help reconstruct the physical laws that governed the birth of the cosmos.

A Geometry for the Universe

The article highlights that positive geometry is not a niche mathematical curiosity but a potential unifying language for form branches of theoretical physics. These geometric frameworks naturally encode the transfer of information between physical systems, for example, by mapping concrete, sensory-based concepts to abstract structures, a process that mirrors how humans metaphorically understand the world.

The mathematics behind this is sophisticated and spans multiple disciplines. The authors draw on algebraic geometry, which defines shapes and spaces through solutions to systems of polynomial equations, algebraic analysis, which studies differential equations through mathematical objects called D-modules, and combinatorics, which describes the arrangements and interactions within these structures.

The formal objects under consideration, such as Feynman integrals, generalized Euler integrals, or canonical forms of positive geometries, are not merely mathematical abstractions. They correspond to observable phenomena in high-energy physics and cosmology, enabling precision computations of particle behavior and cosmic structures alike.

Bridging Scales with Mathematics

The study presents an approach with broad applicability and scalability. Scattering processes are often illustrated using Feynman diagrams. Feynman’s approach in the study of scattering amplitudes boils down to the study of intricate integrals associated to such diagrams. Algebraic geometry provides a range of tools for systematically investigating these integrals.

The graph polynomial of a Feynman diagram is defined in terms of the spanning trees and forests of the underlying graph. The associated Feynman integral can be expressed as a Mellin transform of a power of this graph polynomial, interpreted as a function of its coefficients. These coefficients, however, are constrained by the underlying physical conditions. Feynman integrals are therefore closely connected to generalized Euler integrals, specifically through restrictions to the relevant geometric subspaces. One way to study these holonomic functions is via the linear differential equations they satisfy, which are D-module inverse images of hypergeometric D-modules. Constructing these differential equations explicitly, however, remains challenging. In theoretical cosmology, correlation functions in toy models also take the form of such integrals, with integrands arising from hyperplane arrangements.

The complement of the algebraic variety defined by the graph polynomial in an algebraic torus is a very affine variety, and the Feynman integral can be viewed as the pairing of a twisted cycle and cocycle of this variety. Its geometric and (co-)homological properties reflect physical concepts such as the number of master integrals. These master integrals form a basis for the space of integrals when the kinematic parameters vary, and the size of this basis is, at least generically, equal to the signed topological Euler characteristic of the variety.

A Field in Motion

Fevola and Sattelberger’s work reflects a growing international effort, supported by the ERC synergy grant UNIVERSE+ of Nima Arkani-Hamed, Daniel Baumann, and Johannes Henn, Bernd Sturmfels. It brings together mathematics, particle physics, and cosmology focusing on precisely these connections between algebra, geometry, and theoretical physics. “Positive geometry is still a young field, but it has the potential to significantly influence fundamental research in both physics and mathematics,” the authors emphasize. “It is now up to the scientific community to work out the details of these emerging mathematical objects and theories and to validate them. Encouragingly, several successful collaborations have already laid important groundwork.”

The recent developments are not only advancing our understanding of the physical world but also pushing the boundaries of mathematics itself. Positive geometry is more than a tool. It is a language. One that might unify our understanding of nature at all scales.

Tracking atmospheric methane to its specific sources and quantifying their importance remains a challenge, however. Scientists are pretty good at tracing the sources of the main greenhouse gas, carbon dioxide, to focus on mitigating these emissions. But to trace methane’s origins, scientists often have to measure the isotopic composition of methane’s component atoms, carbon and hydrogen, to use as a fingerprint of various environmental sources.

A new paper by researchers at the University of California, Berkeley, reveals how the activity of one of the main microbial enzymes involved in producing methane affects this isotope composition. The finding could change how scientists calculate the contributions of different environmental sources to Earth’s total methane budget.

“When we integrate all the sources and sinks of carbon dioxide into the atmosphere, we kind of get the number that we’re expecting from direct measurement in the atmosphere. But for methane, large uncertainties in fluxes exist — within tens of percents for some of the fluxes — that challenge our ability to precisely quantify the relative importance and changes in time of the sources,” said UC Berkeley postdoctoral fellow Jonathan Gropp, who is first author of the paper. “To quantify the actual sources of methane, you need to really understand the isotopic processes that are used to constrain these fluxes.”

Gropp teamed up with a molecular biologist and a geochemist at UC Berkeley to, for the first time, employ CRISPR to manipulate the activity of this key enzyme to reveal how these methanogens interact with their food supply to produce methane.

“It is well understood that methane levels are rising, but there is a lot of disagreement on the underlying cause,” said co-author Dipti Nayak, UC Berkeley assistant professor of molecular and cell biology. “This study is the first time the disciplines of molecular biology and isotope biogeochemistry have been fused to provide better constraints on how the biology of methanogens controls the isotopic composition of methane.”

Many elements have heavier or lighter versions, called isotopes, that are found in small proportions in nature. Humans are about 99% carbon-12 and 1% carbon-13, which is slightly heavier because it has an extra neutron in its nucleus. The hydrogen in water is 99.985% hydrogen-1 and 0.015% deuterium or hydrogen-2, which is twice as heavy because it has a neutron in its nucleus.

The natural abundances of isotopes are reflected in all biologically produced molecules and variations can be used to study and fingerprint various biological metabolisms.

“Over the last 70 years, people have shown that methane produced by different organisms and other processes can have distinctive isotopic fingerprints,” said geochemist and co-author Daniel Stolper, UC Berkeley associate professor of earth and planetary science. “Natural gas from oil deposits often looks one way. Methane made by the methanogens within cow guts looks another way. Methane made in deep sea sediments by microorganisms has a different fingerprint. Methanogens can consume or ‘eat’, if you will, a variety of compounds including methanol, acetate or hydrogen; make methane; and generate energy from the process. Scientists have commonly assumed that the isotopic fingerprint depends on what the organisms are eating, which often varies from environment to environment, creating our ability to link isotopes to methane origins.”

“I think what’s unique about the paper is, we learned that the isotopic composition of microbial methane isn’t just based on what methanogens eat,” Nayak said. “What you ‘eat’ matters, of course, but the amount of these substrates and the environmental conditions matter too, and perhaps more importantly, how microbes react to those changes.”

“Microbes respond to the environment by manipulating their gene expression, and then the isotopic compositions change as well,” Gropp said. “This should cause us to think more carefully when we analyze data from the environment.”

The paper will appear Aug. 14 in the journal Science.

Vinegar- and alcohol-eating microbes

Methanogens — microorganisms that are archaea, which are on an entirely separate branch of the tree of life from bacteria — are essential to ridding the world of dead and decaying matter. They ingest simple molecules — molecular hydrogen, acetate or methanol, for example — excreted by other organisms and produce methane gas as waste. This natural methane can be observed in the pale Will-o’-the-wisps seen around swamps and marshes at night, but it’s also released invisibly in cow burps, bubbles up from rice paddies and natural wetlands and leaks out of landfills. While most of the methane in the natural gas we burn formed in association with hydrocarbon generation, some deposits were originally produced by methanogens eating buried organic matter.

The isotopic fingerprint of methane produced by methanogens growing on different “food” sources has been well established in laboratory studies, but scientists have found that in the complexity of the real world, methanogens don’t always produce methane with the same isotopic fingerprint as seen in the lab. For example, when grown in the lab, species of methanogens that eat acetate (essentially vinegar), methanol (the simplest alcohol), or molecular hydrogen (H₂) produce methane, CH₄, with a ratio of hydrogen and carbon isotopes different from the ratios observed in the environment.

Gropp had earlier created a computer model of the metabolic network in methanogens to understand better how the isotope composition of methane is determined. When he got a fellowship to come to UC Berkeley, Stolper and Nayak proposed that he experimentally test his model. Stolper’s laboratory specializes in measuring isotope compositions to explore Earth’s history. Nayak studies methanogens and, as a postdoctoral fellow, found a way to use CRISPR gene editing in methanogens. Her group recently altered the expression of the key enzyme in methanogens that produces the methane — methyl-coenzyme M reductase (MCR) — so that its activity can be dialed down. Enzymes are proteins that catalyze chemical reactions.

Experimenting with these CRISPR-edited microbes — in a common methanogen called Methanosarcina acetivorans growing on acetate and methanol — the researchers looked at how the isotopic composition of methane changed when the enzyme activity was reduced, mimicking what is thought to happen when the microbes are starved for their preferred food.

They found that when MCR is at low concentrations, cells respond by altering the activity of many other enzymes in the cell, causing their inputs and outputs to accumulate and the rate of methane generation to slow so much that enzymes begin running both backwards and forwards. In reverse, these other enzymes remove a hydrogen from carbon atoms; running forward, they add a hydrogen. Together with MCR, they ultimately produce methane (CH₄). Each forward and reverse cycle requires one of these enzymes to pull a hydrogen off of the carbon and add a new one ultimately sourced from water. As a result, the isotopic composition of methane’s four hydrogen molecules gradually comes to reflect that of the water, and not just their food source, which starts with three hydrogens.

This is different from typical assumptions for growth on acetate and methanol that assume no exchange between hydrogen derived from water and that from the food source.

“This isotope exchange we found changes the fingerprint of methane generated by acetate and methanol consuming methanogens vs. that typically assumed. Given this, it might be that we have underestimated the contribution of the acetate-consuming microbes, and they might be even more dominant than we have thought,” Gropp said. “We’re proposing that we at least should consider the cellular response of methanogens to their environment when studying isotopic composition of methane.”

Beyond this study, the CRISPR technique for tuning production of enzymes in methanogens could be used to manipulate and study isotope effects in other enzyme networks broadly, which could help researchers answer questions about geobiology and the Earth’s environment today and in the past.

“This opens up a pathway where modern molecular biology is married with isotope-geochemistry to answer environmental problems,” Stolper said. “There are an enormous number of isotopic systems associated with biology and biochemistry that are studied in the environment; I hope we can start looking at them in the way molecular biologists now are looking at these problems in people and other organisms — by controlling gene expression and looking at how the stable isotopes respond.”

For Nayak, the experiments are also a big step in discovering how to alter methanogens to derail production of methane and redirect their energy to producing useful products instead of an environmentally destructive gas.

“By reducing the amount of this enzyme that makes methane and by putting in alternate pathways that the cell can use, we can essentially give them another release valve, if you will, to put those electrons, which they were otherwise putting in carbon to make methane, into something else that would be more useful,” she said.

Other co-authors of the paper are Markus Bill of Lawrence Berkeley National Laboratory and former UC Berkeley postdoc Rebekah Stein, and Max Lloyd, who is a professor at Penn State University. Gropp was supported by a fellowship from the European Molecular Biology Organization. Nayak and Stolper were funded, in part, by Alfred B. Sloan Research Fellowships. Nayak also is an investigator with the Chan-Zuckerberg Biohub.

NASA’s PREFIRE (Polar Radiant Energy in the Far-InfraRed Experiment) mission has been extended through September 2026 and is broadening its focus from Earth’s poles to the entire globe. The mission’s two shoebox-size CubeSats gauge the capacity of water vapor, clouds, and other elements of Earth’s system to trap heat and keep it from radiating into space. This information can help improve forecasts, including weather severity and storm frequency.

Launched in spring 2024, PREFIRE has been measuring how much heat the planet emits into space from the Arctic and Antarctic. Earth absorbs a significant amount of the Sun’s energy in the tropics. Winds, weather, and ocean currents transport that heat toward the poles, which receive much less sunlight. Ice, snow, and clouds, among other parts of the polar environment, emit some of that heat into space, much of it as far-infrared radiation. The difference between the amount of heat Earth absorbs at the tropics and radiates out from the Arctic and Antarctic is a key influence on the planet’s temperature, helping to drive dynamic systems of climate and weather.

At the core of the mission is a pair of advanced spectrometers designed by NASA’s Jet Propulsion Laboratory in Southern California. They measure wavelengths of light in the far-infrared range of the electromagnetic spectrum and are sensitive to 10 times more far-infrared wavelengths than any similar instrument. This information gives researchers insight into processes associated with surface ice melt and formation, snowmelt and accumulation, and changes in cloud cover.

“The PREFIRE satellites show that at these longer wavelengths, the amount of radiation going into space can differ from one type of ice to another by as much as 5%,” said Brian Drouin, PREFIRE’s project scientist at JPL. “Measurements that look at the same areas but with shorter wavelengths do not show this difference.”

Although the PREFIRE CubeSats have been gathering data on the entire globe, the science team has concentrated their analysis on Earth’s polar regions for its prime mission. Going forward, they will expand their work to include data from the rest of the world.

“We have the capacity to collect data for the whole world, not just the poles. What we’ll be able to do is look at the size of ice particles in clouds that affect energy exchange between Earth and space,” said PREFIRE’s principal investigator, Tristan L’Ecuyer of the University of Wisconsin-Madison. “We’ll be able to incorporate the data into weather prediction models to improve forecasts and improve our understanding of how moisture circulates, which affects where storms form and how precipitation moves around the world.”

The satellites are in what’s called an asynchronous near-polar orbit, traveling near the poles with each pass but hours apart from one another. This provides two snapshots of the same area over time, enabling the mission to capture phenomena that occur on short timescales, such as cloud cover’s temporary effects on the temperature of the area beneath it.

More About PREFIRE

NASA’s Jet Propulsion Laboratory manages PREFIRE for the agency’s Science Mission Directorate and provided the spectrometers. Blue Canyon Technologies built the CubeSats and the University of Wisconsin-Madison processes the data the instruments collect. The launch services provider, Rocket Lab USA Inc. of Long Beach, California, launched both PREFIRE CubeSats from Rocket Lab Launch Complex 1 in New Zealand in May and June 2024.

Spanning 39 feet (12 meters), the drum-shaped antenna reflector on the NISAR (NASA-ISRO Synthetic Aperture Radar) satellite mission from NASA and the Indian Space Research Organisation (ISRO) successfully unfurled in low Earth orbit. The reflector had been stowed, umbrella-like, until the 30-foot (9-meter) boom that supports it could be deployed and locked in place.

Launched by ISRO on July 30 from the Satish Dhawan Space Centre on India’s southeastern coast, NISAR will track the motion of ice sheets and glaciers, the deformation of land due to earthquakes, volcanoes, and landslides, and changes in forest and wetland ecosystems down to fractions of an inch. It also will aid decision-makers in fields as diverse as disaster response, infrastructure monitoring, and agriculture.

“The successful deployment of NISAR’s reflector marks a significant milestone in the capabilities of the satellite,” said Karen St. Germain, director, Earth Science Division at NASA Headquarters in Washington. “From innovative technology to research and modeling to delivering science to help inform decisions, the data NISAR is poised to gather will have a major impact on how global communities and stakeholders improve infrastructure, prepare for and recover from natural disasters, and maintain food security.”

The mission carries the most sophisticated radar systems ever launched as part of a NASA mission. In a first, the satellite combines two synthetic aperture radar (SAR) systems: an L-band system that can see through clouds and forest canopy, and an S-band system that can see through clouds as well but is more sensitive to light vegetation and moisture in snow. The reflector plays a key role for both systems, which is why the successful deployment of the hardware is such a significant milestone.

“This is the largest antenna reflector ever deployed for a NASA mission, and we were of course eager to see the deployment go well. It’s a critical part of the NISAR Earth science mission and has taken years to design, develop, and test to be ready for this big day,” said Phil Barela, NISAR project manager at NASA’s Jet Propulsion Laboratory in Southern California, which managed the U.S. portion of the mission and provided one of the two radar systems aboard NISAR. “Now that we’ve launched, we are focusing on fine-tuning it to begin delivering transformative science by late fall of this year.”

<See link to video at bottom of page.>

How Bloom Works

Weighing about 142 pounds (64 kilograms), the reflector features a cylindrical frame made of 123 composite struts and a gold-plated wire mesh. On Aug. 9, the satellite’s boom, which had been tucked close to its main body, started unfolding one joint at a time until it was fully extended about four days later. The reflector assembly is mounted at the end of the boom.

Then, on Aug. 15, small explosive bolts that held the reflector assembly in place were fired, enabling the antenna to begin a process called the “bloom” — its unfurling by the release of tension stored in its flexible frame while stowed like an umbrella. Subsequent activation of motors and cables then pulled the antenna into its final, locked position.

To image Earth’s surface down to pixels about 30 feet (10 meters) across, the reflector was designed with a diameter about as wide as a school bus is long. Using SAR processing, NISAR’s reflector simulates a traditional radar antenna that for the mission’s L-band instrument would have to be 12 miles (19 kilometers) long to achieve the same resolution.

“Synthetic aperture radar, in principle, works like the lens of a camera, which focuses light to make a sharp image. The size of the lens, called the aperture, determines the sharpness of the image,” said Paul Rosen, NISAR’s project scientist at JPL. “Without SAR, spaceborne radars could generate data, but the resolution would be too rough to be useful. With SAR, NISAR will be able to generate high-resolution imagery. Using special interferometric techniques that compare images over time, NISAR enables researchers and data users to create 3D movies of changes happening on Earth’s surface.”

The NISAR satellite is the culmination of decades of space-based radar development at JPL. Starting in the in the 1970s, JPL managed the first Earth-observing SAR satellite, Seasat, which launched in 1978, as well as Magellan, which used SAR to map the cloud-shrouded surface of Venus in the 1990s.

More About NISAR

The NISAR mission is a partnership between NASA and ISRO spanning years of technical and programmatic collaboration. The successful launch and deployment of NISAR builds upon a strong heritage of cooperation between the United States and India in space. The data produced by NISAR’s two radar systems, one provided by NASA and one by ISRO, will be a testament to what can be achieved when countries unite around a shared vision of innovation and discovery.

The ISRO Space Applications Centre provided the mission’s S-band SAR. The U R Rao Satellite Centre provided the spacecraft bus. Launch services were through Satish Dhawan Space Centre. After launch, key operations, including boom and radar antenna reflector deployment, are being executed and monitored by the ISRO Telemetry, Tracking and Command Network’s global system of ground stations.

Managed by Caltech in Pasadena, JPL leads the U.S. component of the project. In addition to the L-band SAR, reflector, and boom, JPL also provided the high-rate communication subsystem for science data, a solid-state data recorder, and payload data subsystem. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the Near Space Network, which receives NISAR’s L-band data.

The research was conducted primarily in the laboratory of Jean-Philippe Avouac, the Earle C. Anthony Professor of Geology and Mechanical and Civil Engineering and director of the Center for Geomechanics and the Mitigation of Geohazards. Postdoctoral scholar Solène Antoine is the study’s first author. The study is described in a paper appearing in the journal Proceedings of the National Academy of Sciences on August 11.

The Sagaing fault runs in a relatively straight north-to-south line throughout Myanmar. As its two sides slowly move against one another in opposite directions, stress accumulates along the fault. When the stress buildup reaches a breaking point, the fault slips rapidly, causing an earthquake. The Sagaing and San Andreas faults are very similar — both relatively straight strike-slip faults running hundreds of kilometers — and the 2025 Myanmar earthquake, therefore, sheds light on possible future earthquakes on the San Andreas fault.

“This earthquake turned out to be an ideal case to apply image correlation methods [techniques to compare images before and after a geological event] that were developed by our research group,” Antoine says. “They allow us to measure ground displacements at the fault, where the alternative method, radar interferometry, is blind due to phenomenon like decorrelation [a process to decouple signals] and limited sensitivity to north-south displacements.”

Based on studies of historic earthquakes along the Sagaing fault, researchers anticipated that a large earthquake would occur on a 300-kilometer section where no large earthquakes had occurred since 1839. This theory is known as the seismic gap hypothesis: Stuck sections of a fault where there has not been movement are expected to slip to “catch up.” While this section did indeed rupture during the 2025 quake, the fault actually slipped along a total of more than 500 kilometers, indicating that the fault did indeed make up the deficit of slip and more.

In the new study, the team used correlation of satellite optical and radar imagery of the fault — a technique originally developed in the Avouac laboratory and now widely used in seismology — and its surroundings to determine that the 500-kilometer section shifted a net of 3 meters after the quake, that is, the eastern side moved south by 3 meters relative to the western side.

Current models used for seismic hazard assessment are mostly based on earthquake statistics and are time independent, meaning they can only give probabilities of an earthquake during a chosen timespan. For example, these models might estimate, for any given 30-year period and particular area, the probability that an earthquake would exceed a chosen magnitude. However, in order to make truly informed estimates of potential seismic hazards for specific time periods — say, the next 30 years — it is crucial for models to take into account how recently a fault has slipped, where the slip occurred, and by how much.

“The study shows that future earthquakes might not simply repeat past known earthquakes,” Avouac says. “Successive ruptures of a given fault, even as simple as the Sagaing or the San Andreas faults, can be very different and can release even more than the deficit of slip since the last event. In addition, historical records are generally far too short for statistical models to represent the full range of possible earthquakes and eventual patterns in earthquake recurrence. Physics-based models provide an alternative approach with the advantage that they could, in principle, be tuned to observations and used for time-dependent forecast.”

The paper is titled “The 2025 Mw7.7 Mandalay, Myanmar, earthquake reveals complex earthquake cycle with clustering and variable segmentation on Sagaing fault.” In addition to Antoine and Avouac, Caltech co-authors are graduate student Rajani Shrestha, postdoctoral scholar Chris Milliner, and senior research scientist Kyungjae Im. Additional co-authors are Chris Rollins (PhD ’18) of GNS Science Te Pu Ao in New Zealand, Kang Wang of EarthScope Consortium Inc., and Kejie Chen of Southern University of Science and Technology in China. Funding was provided by the Center for Geomechanics and Mitigation of Geohazards, the Statewide California Earthquake Center, the National Science Foundation, and the US Geological Survey.

The radioactive decay of atomic nuclei has been one of the keystones of nuclear physics since the beginning of nuclear research. Now the heaviest nucleus decaying via proton emission has been measured in the Accelerator Laboratory of the University of Jyväskylä, Finland.

“Proton emission is a rare form of radioactive decay, in which the nucleus emits a proton to take a step towards stability,” says Doctoral Researcher Henna Kokkonen from the University of Jyväskylä.

Studying exotic nuclei is difficult, but not impossible

The new nucleus is so far the lightest known isotope of astatine, 188At, consisting of 85 protons and 103 neutrons. Exotic nuclei of this kind are extremely challenging to study due to their short lifetimes and low production cross sections, so precise techniques are needed.

“The nucleus was produced in a fusion-evaporation reaction by irradiating natural silver target with 84Sr ion beam,” says Academy Research Fellow Kalle Auranen from the University of Jyväskylä. “The new isotope was identified using the detector setup of the RITU recoil separator.”

Study reveals new findings on heavy nuclei

In addition to the experimental results, the study expanded a theoretical model to interpret the measured data. Through the model, the nucleus can be interpreted as strongly prolate, i.e. “watermelon shaped.”

“The properties of the nucleus suggests a trend change in the binding energy of the valence proton,” says Kokkonen. “This is possibly explained by an interaction unprecedented in heavy nuclei.”

The study is a follow-up to the master’s thesis

The study is part of Kokkonen’s doctoral thesis and a direct scientific follow-up to her master’s thesis, in which she discovered a new type of atomic nucleus, the 190-astatatine. The thesis article was published in the Physical Review C journal in 2023.

“Isotope discoveries are rare worldwide, and this is the second time I have had the opportunity to be part of making history,” Kokkonen rejoices. “Every experiment is challenging, and it feels great to do research that improves understanding of the limits of matter and the structure of atomic nuclei.”

The research article was written as part of an international research collaboration involving experts in theoretical nuclear physics. The study was published in the renowned Nature Communications.

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.”