Observations of an unusual cosmic-dawn source illuminate how early supermassive black holes may have grown rapidly in a gas-enshrouded state; such enshrouded black holes may lie at the heart of the ‘little red dots’
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The biggest black hole merger ever observed could be less massive than it appears
Gravitational waves are ripples in spacetime created when pairs of black holes spiral into each other and eventually merge. But if this ripple has been warped by another massive object on its way to Earth, a new analysis suggests that these black holes might appear far larger than they really are.
In the analysis published in The Astrophysical Journal Letters, Miguel Zumalacárregui and colleagues at the Max Planck Institute for Gravitational Physics revisit the signal from what appeared to be the largest black hole merger ever recorded. They conclude that the objects were likely far lighter than first thought.
Brain activity patterns could help sharpen LLM deductive reasoning
Large language models (LLMs), the artificial intelligence systems underpinning the functioning of ChatGPT, Gemini and other similar conversational agents, are now widely used worldwide. In addition to processing, interpreting and generating texts, some of these models can solve basic logical problems and answer some user questions with striking accuracy.
While various past studies assessed the reasoning capabilities of some LLMs, how these models encode information to make logical predictions is poorly understood. In particular, the extent to which their activity patterns while processing reasoning problems resemble those in areas of the human brain linked with reasoning remains unclear.
Researchers at Peking University and Tsinghua University recently carried out a study comparing brain activity patterns during reasoning with the numerical patterns through which LLMs process information while generating logical answers to questions. Their paper, published in Nature Machine Intelligence, suggests that language models and the human brain represent deductive reasoning in similar, but not identical, ways, while also showing that LLM representations could potentially be steered using brain imaging data.
Transparent silicon-photonics chips could bring advanced optical systems to curved displays
The field of silicon photonics, which uses light rather than electricity to transmit and process data on semiconductor chips, has enabled optical systems to evolve from bulky setups to compact, advanced systems. Typically, however, these silicon-photonics chips are rigid and opaque.
MIT scientists have now figured out a scalable way to make silicon-photonics chips flexible and transparent, opening a route to advanced microchips that could be used in applications such as discrete health monitors that conform to the body or transparent augmented-reality displays that fit the curve of a pilot’s helmet.
While scientists have recently performed lab demonstrations of chips that were flexible or transparent, they could only fabricate a few devices at a time.
Cancer medication helps reduce SIV reservoir, increasing hope for HIV cure
Emory University researchers have provided the first proof of concept in a nonhuman primate model for eliminating HIV-infected cells with venetoclax, a clinically approved cancer medication. Venetoclax effectively targets and blocks Bcl-2, a protein that not only regulates whether cells live or die but also promotes the survival of cancer cells. Similarly, Bcl-2 is a culprit in sustaining HIV cell reservoirs.
The research team determined that venetoclax is also effective at reducing simian immunodeficiency virus (SIV) reservoir levels in vivo when given as part of a combination treatment for HIV. The results are reported in Nature Microbiology, and two clinical trials are underway to test venetoclax in people living with HIV.
“Eliminating the viral reservoir is a priority in the pursuit of a cure for HIV,” says Mirko Paiardini, Ph.D., senior author. “Despite many attempts, there hasn’t been a therapeutic strategy able to do this. Our study, however, offers hope for accelerating the timeline for a cure by using an approved medication.”
Quantum-optical spin glass could improve how AI remembers and learns
A new study has demonstrated that it is possible to make a network of atoms and photons that could improve how artificial intelligence stores and recalls memories. This network, called a quantum-optical spin glass, works as an associative memory, a form of AI that enables the recall of full memories from partial information—much like how humans can recognize a person’s face in a blurred photograph.
The advance, published in Science, shows that this new type of spin glass has a greater capacity to hold and recall memories than a traditional AI network of the same size. The atom-and-photon network also exhibited short-term plasticity, a phenomenon that resembles how synaptic connections between neurons in the brain change when learning new information.
“We can now make neural networks at the atomic level, and they adjust themselves in a way that is somewhat similar to how we believe our brains learn,” said Benjamin Lev, the study’s senior author and the Stanford Fortitude Professor and professor of physics and applied physics in the School of Humanities and Sciences.
AI suggests new physics experiments that could outperform human-designed setups
Research means asking questions of the universe. For centuries, clever minds have advanced science by devising ingenious experiments designed so their results reveal something about the laws of nature as clearly and unambiguously as possible.
An international research team has now asked: Can this process be automated? Can artificial intelligence develop new ideas for experiments? The answer is a clear yes. In various areas of physics, AI can propose experiments that enable more precise results than experiments designed by humans.
In the journal Nature, the team presented the current state of this new approach to research.
BESIII sets world’s most stringent direct limit on Lambda hyperon electric dipole moment
The BESIII Collaboration, led by the Institute of High Energy Physics of the Chinese Academy of Sciences, has achieved the world’s most precise measurement of the electric dipole moment (EDM) of the Lambda (Λ) hyperon using quantum-entangled Λ–anti-Λ pairs produced in J/ψ decays. The result improves the experimental sensitivity by about three orders of magnitude compared with the previous measurement, providing a new way to probe charge-parity (CP) violation in particles containing strange quarks.
The study is published in Science.
One of the most profound mysteries in modern physics is why the observable universe is dominated by matter rather than antimatter. Although the Standard Model has been remarkably successful in describing elementary particles and their interactions, its known sources of CP violation are insufficient to account for this cosmic imbalance. Searching for additional sources of CP violation is therefore an important path toward physics beyond the Standard Model.
Scientists Just Challenged a Century-Old Theory of How Crystals Form
3D atomic imaging of advanced materials provides new insights into transitions such as liquids freezing into solids.
For nearly a century, scientists have relied on classical nucleation theory to explain how phase transitions such as freezing and condensation get started. The theory describes how small, ordered regions called nuclei emerge within disordered matter, and a central equation behind that picture has been supported by thousands of experiments.
But when UCLA-led researchers examined crystal formation atom by atom in three dimensions, the nuclei did not look the way the classical model predicts.
Scientists Expose Unexpected Driver of the May 2024 Superstorm
Even though the solar wind was unusually dense during the May 2024 superstorm, ions from the solar wind contributed very little to the ring current, marking the first time both were observed simultaneously during a storm of this magnitude.
In May 2024, auroras spread into skies far beyond their usual range, appearing at unusually low latitudes around the world. Far above those displays, inside Earth’s magnetosphere, measurements were capturing something never before seen during a geomagnetic storm of this magnitude.
The storm began when a large sunspot unleashed a rapid sequence of powerful solar eruptions. Multiple clouds of magnetized plasma merged on their way through space before striking Earth’s magnetosphere, the region dominated by our planet’s magnetic field. The resulting disturbance was the strongest ever measured directly in Earth’s ring current region, a belt of charged particles surrounding the planet.