Physicists observe key evidence of unconventional superconductivity in magic-angle graphene

MIT researchers observed clear signatures of unconventional superconductivity in magic-angle twisted trilayer graphene (MATTG). The image illustrates pairs of superconducting electrons (yellow spheres) traveling through MATTG, as the team’s new method (represented by magnifying glass) probes the material’s unconventional superconducting gap (represented by the V-shaped beam).
Image Credit: Sampson Wilcox and Emily Theobald, MIT RLE

Superconductors are like the express trains in a metro system. Any electricity that “boards” a superconducting material can zip through it without stopping and losing energy along the way. As such, superconductors are extremely energy efficient, and are used today to power a variety of applications, from MRI machines to particle accelerators.

But these “conventional” superconductors are somewhat limited in terms of uses because they must be brought down to ultra-low temperatures using elaborate cooling systems to keep them in their superconducting state. If superconductors could work at higher, room-like temperatures, they would enable a new world of technologies, from zero-energy-loss power cables and electricity grids to practical quantum computing systems. And so scientists at MIT and elsewhere are studying “unconventional” superconductors — materials that exhibit superconductivity in ways that are different from, and potentially more promising than, today’s superconductors.

In a promising breakthrough, MIT physicists have today reported their observation of new key evidence of unconventional superconductivity in “magic-angle” twisted tri-layer graphene (MATTG) — a material that is made by stacking three atomically-thin sheets of graphene at a specific angle, or twist, that then allows exotic properties to emerge.

Physicists discover new state of matter in electrons, platform to study quantum phenomena

From left, researchers Cyprian Lewandowski, Aman Kumar and Hitesh Changlani.
Photo Credit: Devin Bittner/FSU College of Arts and Sciences

Electricity powers our lives, including our cars, phones, computers and more, through the movement of electrons within a circuit. While we can’t see these electrons, electric currents moving through a conductor flow like water through a pipe to produce electricity.

Certain materials, however, allow that electron flow to “freeze” into crystallized shapes, triggering a transition in the state of matter that the electrons collectively form. This turns the material from a conductor to an insulator, stopping the flow of electrons and providing a unique window into their complex behavior. This phenomenon makes possible new technologies in quantum computing, advanced superconductivity for energy and medical imaging, lighting, and highly precise atomic clocks. 

A team of Florida State University-based physicists, including National High Magnetic Field Laboratory Dirac Postdoctoral Fellow Aman Kumar, Associate Professor Hitesh Changlani and Assistant Professor Cyprian Lewandowski, have shown the conditions necessary to stabilize a phase of matter in which electrons exist in a solid crystalline lattice but can “melt” into a liquid state, known as a generalized Wigner crystal. Their work was published in npj Quantum Materials, a Nature publication. 

The Saltwater Formula

Mannum Waterfalls in South Australia
Photo Credit: © denisbin Creative Commons 2.0  

A solution to a tricky groundwater riddle from Australia: Researchers at TU Wien have developed numerical models to simulate the movement of fluids in porous materials.

Things are complicated along the Murray–Darling River in southern Australia. Agricultural irrigation washes salt out of the upper soil layers, and this salt eventually ends up in the river. To prevent the river’s salt concentration from rising too much, part of the salty water is diverted into special basins. Some of these basins are designed to let the salty water evaporate, others to slowly release it in a controlled manner in the underground. That keeps salt temporarily out of the river and allows a better management of the river’s water—but increases the salinity in the ground. How can we calculate how this saltwater spreads underground and what its long-term effects will be?

Such questions are extremely difficult to answer, as several physical effects interact in complex ways. At TU Wien, researchers have now developed an efficient computer model that can run on supercomputers to calculate the spreading of fluids in porous materials—allowing the movement of saltwater in the soils, like in the case of the Murray–Darling River, to be predicted much more accurately. The same approach can also be applied to other problems, such as the dispersion of pollutants in groundwater.

Birch leaves and peanuts turned into advanced laser technology

Upper: The biomaterial-based random laser when activated. Lower: The same laser seen in daylight.
 Photo Credit: Zhihao Huang

Physicists at Umeå University, in collaboration with researchers in China, have developed a laser made entirely from biomaterials – birch leaves and peanut kernels. The environmentally friendly laser could become an inexpensive and accessible tool for medical diagnostics and imaging.

The results have been published in the scientific journal Nanophotonics and show how a so-called random laser can be made entirely from biological materials.

“Our study shows that it is possible to create advanced optical technology in a simple way using only local, renewable materials,” says Jia Wang, Associate Professor at the Department of Physics, Umeå University, and one of the authors of the study.

A random laser is a type of laser in which light scatters many times inside a disordered material before emerging as a focused beam. It holds great promise for applications such as medical imaging and early disease detection, and has therefore attracted significant research attention. However, conventional random laser materials are often toxic or expensive and complex to produce.

The crystal that makes clouds rain

The experiments have to be performed in the dark
Photo Credit: Technische Universität Wien

No one can control the weather, but certain clouds can be deliberately triggered to release rain or snow. The process, known as cloud seeding, typically involves dispersing small silver iodide particles from aircraft into clouds. These particles act as seeds on which water molecules accumulate, forming ice crystals that grow and eventually become heavy enough to fall to the ground as rain or snow.

Until now, the microscopic details of this process have remained unclear. Using high-resolution microscopy and computer simulations, researchers at TU Wien have investigated how silver iodide interacts with water at the atomic scale. Their findings reveal that silver iodide exposes two fundamentally different surfaces, but only one of them promotes ice nucleation. The discovery deepens our understanding of how clouds form rain and snow and may guide the design of improved materials for inducing precipitation.

How constant is the fine structure constant?

The thorium crystal 
The core element of the experiment: a crystal containing thorium atoms.
Photo Credit: Technische Universität Wien

Thorium atomic nuclei can be used for very specific precision measurements. This had been suspected for decades, and the search for suitable atomic nucleus states had been ongoing worldwide. In 2024, a team from TU Wien, with the support of international partners, achieved the decisive breakthrough: the long-discussed thorium nuclear transition was found. Shortly afterwards, it was demonstrated that thorium can indeed be used to build high-precision nuclear clocks.

Now the next major success in high-precision research on thorium nuclei has been achieved: when the thorium nucleus changes between different states, it slightly alters its elliptical shape. This also changes the distribution of protons in the nucleus, which in turn alters its electric field. This can be measured so precisely that it allows for better investigation than ever before of the fine structure constant, one of the most important natural constants in physics. This now makes it possible to investigate the question of how constant the fundamental constants of nature really are.

Neutrinos ‘flavor’ may hold clues to the universe’s biggest secrets

Inside the Super-Kamiokande detector.
Photo Credit: Kamioka Observatory, ICRR (Institute for Cosmic Ray Research), The University of Tokyo.

In a new analysis, physicists provide the most precise picture yet of how neutrinos change ‘flavor’ as they travel through the cosmos. 

Neutrinos are fundamental particles of the universe, but also some of the most elusive; They pass through everything and can be extremely difficult to detect. While many of their properties are mysterious, scientists know neutrinos come in three types: electron, muon, and tau. 

Understanding these different identities can help scientists learn more about neutrino masses and answer key questions about the evolution of the universe, including why matter came to dominate over antimatter in the early universe, said Zoya Vallari, 

Exotic roto-crystals

Spontaneous fragmentation of a rotating crystal comprised of transversely interacting particles into multiple rotating crystal fragments.
Image Credit: Wayne State University/Zhi-Feng Huang

It sounds bizarre, but they exist: crystals made of rotating objects. Physicists from Aachen, Düsseldorf, Mainz and Wayne State (Detroit, USA) have jointly studied these exotic objects and their properties. They easily break into individual fragments, have odd grain boundaries and evidence defects that can be controlled in a targeted fashion. In an article published in the Proceedings of the National Academy of Sciences, the researchers outline how several new properties of such “transverse interaction” systems can be predicted by applying a comprehensive theory.

“Transverse forces” can occur in synthetic systems, such as in certain magnetic solids. They exist in systems of living organisms too, however. In an experiment observing a host of starfish embryos conducted at American university MIT, it was found that, through their swimming movements, the embryos influence each other in a manner leading them to rotate around one another. What biological function this may have is not yet understood. The common thread in these systems is that they involve rotating objects.

The key to why the universe exists may lie in an 1800s knot idea science once dismissed

The model suggests a brief “knot-dominated era,” when these tangled energy fields outweighed everything else, a scenario that could be probed through gravitational-wave signals.
Image Credit: Courtesy of Muneto Nitta/Hiroshima University

In 1867, Lord Kelvin imagined atoms as knots in the aether. The idea was soon disproven. Atoms turned out to be something else entirely. But his discarded vision may yet hold the key to why the universe exists.

Now, for the first time, Japanese physicists have shown that knots can arise in a realistic particle physics framework, one that also tackles deep puzzles such as neutrino masses, dark matter, and the strong CP problem. Their findings, in Physical Review Letters, suggest these “cosmic knots” could have formed and briefly dominated in the turbulent newborn universe, collapsing in ways that favored matter over antimatter and leaving behind a unique hum in spacetime that future detectors could listen for—a rarity for a physics mystery that’s notoriously hard to probe.

“This study addresses one of the most fundamental mysteries in physics: why our Universe is made of matter and not antimatter,” said study corresponding author Muneto Nitta, professor (special appointment) at Hiroshima University’s International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM2) in Japan.

“This question is important because it touches directly on why stars, galaxies, and we ourselves exist at all.”

The Quantum Door Mystery: Electrons That Can’t Find the Exit

Photo Credit: © Technische Universität Wien

What happens when electrons leave a solid material? This seemingly simple phenomenon has eluded accurate theoretical description until now. Researchers have found the missing piece of the puzzle.

Imagine a frog sitting inside a box. The box has a large opening at a certain height. Can the frog escape? That depends on how much energy it has: if it can jump high enough, it could in principle make it out. But whether it actually succeeds is another question. The height of the jump alone isn’t enough — the frog also needs to jump through the opening.

A similar situation arises with electrons inside a solid. When given a bit of extra energy — for example, by bombarding the material with additional electrons — they may be able to escape from the material. This effect has been known for many years and is widely used in technology. But surprisingly, it has never been possible to calculate this process accurately. A collaboration between several research groups at TU Wien has now solved this mystery: just like the frog, it’s not only the energy that matters — the electron also needs to find the right “exit,” a so-called “doorway state.”

Physicists probe quark‑gluon plasma temperatures, helping paint more detailed picture of big bang

Frank Geurts is a professor of physics and astronomy at Rice and co-spokesperson of the RHIC STAR collaboration.
Photo Credit: Jeff Fitlow/Rice University.

A research team led by Rice University physicist Frank Geurts has successfully measured the temperature of quark-gluon plasma (QGP) at various stages of its evolution, providing critical insights into a state of matter believed to have existed just microseconds after the big bang, a scientific theory describing the origin and evolution of the universe. 

The study addresses the long-standing challenge of measuring the temperature of matter under extreme conditions where direct access is impossible. By using thermal electron-positron pairs emitted during ultrarelativistic heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in New York, the researchers have decoded the thermal profile of QGP. 

Temperature measurements existed previously but have been plagued by several complications such as whether they were of the QGP phase or biased by a Doppler-like effect from the large velocity fields pushing such effective temperatures.

“Our measurements unlock QGP’s thermal fingerprint,” said Geurts, a professor of physics and astronomy and co-spokesperson of the RHIC STAR collaboration. “Tracking dilepton emissions has allowed us to determine how hot the plasma was and when it started to cool, providing a direct view of conditions just microseconds after the universe’s inception.” 

Metamaterials can stifle vibrations with intentional complexity

This 3-D printed “kagome tube” can passively isolate vibrations using its complex, but deliberate, structure.
Image Credit: James McInerney, Air Force Research Laboratory

In science and engineering, it’s unusual for innovation to come in one fell swoop. It’s more often a painstaking plod through which the extraordinary gradually becomes ordinary.

But we may be at an inflection point along that path when it comes to engineered structures whose mechanical properties are unlike anything seen before in nature, also known as mechanical metamaterials. A team led by researchers at the University of Michigan and the Air Force Research Laboratory, or AFRL, have shown how to 3D print intricate tubes that can use their complex structure to stymy vibrations.

Such structures could be useful in a variety of applications where people want to dampen vibrations, including transportation, civil engineering and more. The team’s new study, published in the journal Physical Review Applied, builds on decades of theoretical and computational research to create structures that passively impede vibrations trying to move from one end to the other.

Russian Physicists Found a Way to Speed Up the Process of Developing Solar Panels

According to Ivan Zhidkov, this method allows for the quick selection of only promising materials.
 Photo Credit: Rodion Narudinov

Physicists at Ural Federal University and their colleagues from the Institute of Problems of Chemical Physics of the Russian Academy of Science (IPCP RAS) have found a way to significantly reduce the thousands of hours required for developing perovskite solar panel technology. Scientists have proposed a method that allows us  to determine in a few hours whether solar panels will fail quickly or if the development is promising with a potentially long service life. The test results were published in the journal Physica B: Condensed Matter.

Perovskite films are promising energy converters for various photoelectronic devices, such as solar cells, LEDs, and photodetectors. They have excellent optoelectronic properties and can be grown relatively easily at a low production cost.

Extra Silver Atom Sparks Breakthrough in Photoluminescence of Silver Nanoclusters

Structural architectures of anion-templated (a) Ag78 and (b) Ag79 NCs. Hydrogen atoms are omitted for clarity.
Image Credit: ©Yuichi Negishi et al.

A team of researchers from Tohoku University, Tokyo University of Science, and the Institute for Molecular Science have uncovered how the precise addition of a single silver (Ag) atom can dramatically transform the light-emitting properties of high-nuclear Ag nanoclusters (NCs). The study reports a remarkable 77-fold increase in photoluminescence (PL) quantum yield (QY) at room temperature - a milestone that paves the way for practical applications in optoelectronics and sensing technologies. The findings were published in the Journal of the American Chemical Society.

Photoluminescence quantum yield is an important metric used to evaluate the efficiency of photoluminescence, which is how well a material can absorb energy and convert it into light. Improving PLQY positively impacts technology such as OLEDs in TV screens.

Finding treasures with physics: the fingerprint matrix

Left: Artistic impression of metal spheres buried in small glass beads. Middle: Conventional ultrasound picture. Right: With the new technology, the positions of the metal spheres can be precisely determined.
Image Credit: © TU Wien / Arthur Le Ber

How do you find objects buried in sand or hidden in thick fog? A team from the Institut Langevin (Paris) and TU Wien (Vienna) has developed an astonishing method.

Can we reveal objects that are hidden in environments completely opaque to the human eye? With conventional imaging techniques, the answer is no: a dense cloud or layer of material blocks light so completely that a simple photograph contains no information about what lies behind it.

However, a research collaboration between the Institut Langevin and TU Wien has now shown that, with the help of innovative mathematical tricks, objects can be detected even in such cases – using what is known as the ‘fingerprint matrix’. The team tested the newly developed method on metal objects buried in sand and in applications in the field of medical imaging. A joint publication on this topic has just appeared in the journal Nature Physics.

Scientists uncover room-temperature route to improved light-harvesting and emission devices

Dasom Kim
Photo Credit: Jorge Vidal/Rice University

Atoms in crystalline solids sometimes vibrate in unison, giving rise to emergent phenomena known as phonons. Because these collective vibrations set the pace for how heat and energy move through materials, they play a central role in devices that capture or emit light, like solar cells and LEDs.

A team of researchers from Rice University and collaborators have found a way to make two different phonons in thin films of lead halide perovskite interact with light so strongly that they merge into entirely new hybrid states of matter. The finding, reported in a study published in Nature Communications, could provide a powerful new lever for controlling how perovskite materials harvest and transport energy.

To get a specific light frequency in the terahertz range to interact with phonons in the halide perovskite crystals, the researchers fabricated nanoscale slots ⎯ each about a thousand times thinner than a sheet of cling wrap ⎯ into a thin layer of gold. The slots acted like tiny metallic traps for light, tuning its frequency to that of the phonons and thus giving rise to a strong form of interaction known as “ultrastrong coupling.”

Scientists solve mystery of loop current switching in Kagome metals

Structure and electron behavior in kagome metals: (A) The triangular atomic arrangement showing how tiny electrical currents flow in loops. (B) How electrons organize into wave-like density patterns. (C) How electrons normally move through the material. (D) How electron movement is affected by the wave patterns. (E) The special combined state where both loop currents and wave patterns exist together, creating the conditions for magnetic switching.
Image Credit: Tazai et al., 2025

Quantum metals are metals where quantum effects—behaviors that normally only matter at atomic scales—become powerful enough to control the metal's macroscopic electrical properties. 

Researchers in Japan have explained how electricity behaves in a special group of quantum metals called kagome metals. The study is the first to show how weak magnetic fields reverse tiny loop electrical currents inside these metals. These switching changes the material's macroscopic electrical properties and reverses which direction has easier electrical flow, a property known as the diode effect, where current flows more easily in one direction than the other.  

More Signs of Phase-change 'Turbulence' in Nuclear Matter

 A view from the ground up of the three-story STAR detector at the Relativistic Heavy Ion Collider (RHIC).
Image Credit: Brookhaven National Laboratory

Members of the STAR Collaboration, a group of physicists collecting and analyzing data from particle collisions at the Relativistic Heavy Ion Collider (RHIC), have published a new high-precision analysis of data on the number of protons produced in gold-ion smashups over a range of energies. The results, published in Physical Review Letters, suggest one part of a key signature of a so-called “critical point.” That’s a unique point on the “map” of nuclear phases that marks a change in the way quarks and gluons, the building blocks of protons and neutrons, transform from one phase of matter to another.

Discovering the critical point has been a central goal of research at RHIC, a U.S. Department of Energy (DOE) Office of Science user facility for nuclear physics research at DOE’s Brookhaven National Laboratory. Like centuries-old efforts to map out the solid, liquid, and gaseous phases of substances like water, it’s considered essential for fully understanding and describing the quark-gluon plasma. This unique form of nuclear matter is generated by RHIC’s most energetic nuclear collisions, which effectively “melt” the protons and neutrons that make up the colliding gold ions, briefly liberating their innermost building blocks to form a nearly perfect fluid state that once filled our early universe.

New type of time crystals discovered

Time crystal 
Correlations between quantum particles result in a rhythmic signal – without the need for an external beat to set the tempo.
Image Credit: © TU Wien

Nature has many rhythms: the seasons result from the Earth's movement around the sun; the ticking of a pendulum clock results from the oscillation of its pendulum. These phenomena can be understood with very simple equations.

However, regular rhythms can also arise in a completely different way – by themselves, without an external clock, through the complex interaction of many particles. Instead of uniform disorder, a fixed rhythm emerges – this is referred to as a ‘time crystal’. Calculations by TU Wien (Vienna) now show that such time crystals can also be generated in a completely different way than previously thought. The quantum physical correlations between the particles, which were previously thought to be harmful for the emergence of such phenomena, can actually stabilize time crystals. This is a surprising new insight into the quantum physics of many-particle systems.

Mixing neutrinos of colliding neutron stars changes how merger unfolds

New simulations of neutron star mergers reveal that the mixing and changing of tiny particles called neutrinos impacts how the merger unfolds, including the composition and structure of the merger remnant as well as the resulting emissions. This image depicts the density of neutrinos within the remnant as varying textures, and the colors represent energy densities of different neutrino flavors.
 Image Credit: Provided by the Radice research group / Pennsylvania State University
(CC BY-NC-ND 4.0)

The collision and merger of two neutron stars — the incredibly dense remnants of collapsed stars — are some of the most energetic events in the universe, producing a variety of signals that can be observed on Earth. New simulations of neutron star mergers by a team from Penn State and the University of Tennessee Knoxville reveal that the mixing and changing of tiny particles called neutrinos that can travel astronomical distances undisturbed impacts how the merger unfolds, as well as the resulting emissions. The findings have implications for longstanding questions about the origins of metals and rare earth elements as well as understanding physics in extreme environments, the researchers said.

The paper, published in the journal Physical Review Letters, is the first to simulate the transformation of neutrino “flavors” in neutron star mergers. Neutrinos are fundamental particles that interact weakly with other matter, and come in three flavors, named for the other particles they associate with: electron, muon and tau. Under specific conditions, including the inside of a neutron star, neutrinos can theoretically change flavors, which can change the types of particles with which they interact.