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What if dark matter came in two states?

The absence of a signal could itself be a signal. This is the idea behind a new study published in the Journal of Cosmology and Astroparticle Physics, which aims to redefine how we search for dark matter, showing that it may not be necessary to find the same “clues” everywhere in order to interpret it.

In particular, the study suggests that even if we observe a certain type of signal at the center of our galaxy—an excess of gamma radiation that could result from the annihilation of dark matter particles—failing to detect the same signal in other systems, such as dwarf galaxies, is not enough to rule out this explanation.

Dark matter, in fact, may not consist of a single particle, but of multiple slightly different components, whose behavior varies depending on the cosmic environment.

Physicists zero in on the mass of the fundamental W boson particle

When fundamental particles are heavier or lighter than expected, physicists’ understanding of the universe can tip into the unknown. A particle that is just beyond its predicted mass can unravel scientists’ assumptions about the forces that make up all of matter and space. But now, a new precision measurement has reset the balance and confirmed scientists’ theories, at least for one of the universe’s core building blocks.

In a paper appearing in the journal Nature, an international team including MIT physicists reports a new, ultraprecise measurement of the mass of the W boson.

The W boson is one of two elementary particles that embody the weak force, which is one of the four fundamental forces of nature. The weak force enables certain particles to change identities, such as from protons to neutrons and vice versa. This morphing is what drives radioactive decay, as well as nuclear fusion, which powers the sun.

Sound-sensing hair bundles in our ears act as tiny thermodynamic machines

The hair cells lining the inner ear are among the most sophisticated structures in the human body: capable of detecting sounds as faint as a whisper, while helping to maintain our sense of balance. Through new models detailed in PRX Life, a team led by Roman Belousov at the European Molecular Biology Laboratory has revealed for the first time how oscillating bundles attached to these cells operate in different thermodynamic regimes—offering a new framework for understanding how our hearing works at a fundamental level.

Within the inner ear, each hair cell hosts a hair “bundle”: a cluster of tiny, bristle-like projections that vibrate in response to incoming sound waves. The mechanical energy from these oscillations is then converted into electrical signals which travel to the brain. Rather than being passive receivers, these bundles actively oscillate —driven by molecular motors within the cell that allow them to amplify faint signals and tune in to specific frequencies.

But despite decades of study, researchers are still unclear on the connection between this active oscillation and the hair bundle’s response to external sound. Existing models tended to treat bundles as if they were moving spontaneously, without accounting for what happens when they actually interact with sound.

AI uncovers hidden immune defenses inside bacteria

Researchers at the Massachusetts Institute of Technology (MIT) have discovered thousands of new proteins that protect bacteria from virus attacks using an AI system called DefensePredictor. What would usually take months of lab work can now be narrowed down to promising candidates in minutes.

Bacteria are under constant attack from viruses called bacteriophages. One of their most powerful defenses is CRISPR-Cas, a system that cuts up viral DNA to stop an infection and is now a valuable biotechnology tool for precisely editing genes in a lab.

Traditional methods of finding these defenses are long and laborious, equivalent to looking for a needle in a haystack. They involve searching for nearby known defensive genes and manually testing thousands of DNA fragments. But now, AI can take the strain.

AI trained like a Rubik’s Cube solver simplifies particle physics equations

For years, Rutgers physicist David Shih solved Rubik’s Cubes with his children, twisting the colorful squares until the scrambled puzzle returned to order. He didn’t expect the toy to connect to his research, but recently he realized the logic behind the puzzle was exactly what he needed to solve a problem involving particle physics.

That idea led to a new artificial intelligence (AI) method that can simplify some of the extremely complex equations used in particle physics. Shih described the method in a study posted to the arXiv preprint server, a widely used site where scientists share new research.

“In reaching our solutions, we found that an analogy between mathematical simplification and solving Rubik’s Cubes was key,” said Shih, a professor in the Department of Physics and Astronomy at the Rutgers School of Arts and Sciences. “Both can be viewed as scrambling and unscrambling problems.”

Summer is getting longer, and it’s happening faster than we thought

Summer weather is arriving earlier, lasting longer and packing more heat than it used to—and it’s happening faster than scientists had previously measured. A new study by UBC researchers has found that between 1990 and 2023, the average summer between the tropics and the polar circles grew about six days longer per decade. That’s up from roughly four days per decade found in past research investigations up until the early 2010s.

For many cities, the numbers are even more striking. In Sydney, Australia, summer temperatures now last about 130 days, up from 80 days in 1990, adding 15 days per decade. Toronto summers are expanding by eight days per decade.

The researchers didn’t use the calendar definition of summer (June through August in the Northern Hemisphere and December through February in the Southern Hemisphere). Instead, they defined summer based on the weather: the stretch of days each year when temperatures rise above what was historically typical for a given location during the warmest part of the year—a threshold set using climate data from 1961 to 1990.

Robust against noise, geometric-phase swap gates bring stability to quantum operations

Researchers at ETH Zurich have realized particularly stable quantum logical operations with qubits made of neutral atoms. Since these operations, called quantum gates, are based on geometric phases, they are extremely robust against experimental noise and can be used in quantum computers in the future.

Quantum bits, or qubits, which are required for building quantum computers, come in different kinds. In recent years, many research institutes and companies have focused on superconducting circuits and trapped ions. However, neutral atoms trapped with laser light also have a lot going for them: since they carry no electric charge, they are less sensitive to disturbances. Moreover, trapping with laser light makes it easy to realize several thousand qubits in a single system—using superconductors or ions this is much more difficult.

Nevertheless, neutral atoms have their own problems. In quantum computers, qubits exist in superposition states of the logic values 0 and 1. To perform calculations with them, one needs to execute quantum logic operations, also known as quantum gates.

Safer sodium battery eliminates thermal runaway with a heat-triggered polymer barrier

Some batteries have been known to catch fire or explode at high temperatures or when under stress. This safety concern has pushed researchers to experiment with different ways to design safer batteries that can ideally still perform reliably and efficiently. Sodium-ion batteries (NIBs) are considered a promising alternative to lithium-ion batteries, but still face safety risks, especially at high capacities. But now, a team of researchers in China has designed a new type of electrolyte for NIBs that may eliminate these risks, allowing for stable performance across a wide temperature range.

The main risk associated with batteries involves a process called thermal runaway. Thermal runaway is a rapid and uncontrolled increase in temperature that occurs when heat generation exceeds heat dissipation. This can lead to intense, self-sustaining fires or explosions that are exceptionally difficult to extinguish, release toxic gases, and can even reignite after being extinguished.

Some electrolytes are designed to be “nonflammable,” often by using phosphate esters or fluorinated compounds. However, most nonflammable electrolytes only prevent fire, and do not fully eliminate thermal runaway in large batteries. The team involved in the new study notes that the thermal stability of the electrolyte, the stability of the electrode–electrolyte interfaces and the interactions between the anode and cathode at high temperatures must be considered comprehensively when creating a truly safe battery that can resist thermal runaway.

Prototype chip could boost efficiency of power management in data centers

In an effort to meet the rising energy demands of data centers, engineers at the University of California San Diego have developed a new chip design that could improve how graphics processing units (GPUs) convert and manage power. The technology demonstrates a more efficient way to perform a critical task in electronics: converting high voltages into lower levels required by computing hardware. In lab tests, a prototype chip performed the type of voltage conversion used in modern data centers with high efficiency.

The advance, published in Nature Communications, could lead to the development of smaller, more energy-efficient systems for advanced computing.

Leather gets a power upgrade with laser-written microsupercapacitors

Researchers have developed a simple and eco-friendly way to use a laser to turn natural leather into flexible and wearable energy devices. The new approach could lay the groundwork for more sustainable wearable electronics. In a paper in Optics Letters, the researchers demonstrate the new technique by creating microsupercapacitors on leather in various patterns, including a tiger, dragon and rabbit.

“Using a laser, we directly write conductive patterns onto vegetable-tanned leather to create microsupercapacitors that can store energy and help smooth electrical signals so that wearable electronics run more reliably,” said the research team leader Dong-Dong Han from Jilin University in China.

Unlike conventional devices that rely on synthetic materials and complex, chemical-heavy processes, our approach uses a natural, skin-friendly material and a one-step fabrication method. The microsupercapacitors are well-suited for flexible and comfortable wearable electronics because they are built on soft materials and can be shaped freely and integrated directly into products.

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