Mickey Mouse and Minnie Mouse floats at the Magic Kingdom Park at Walt Disney World in Orlando, Florida, on 3 April 2025. Mickey Mouse and Minnie Mouse floats at the Magic Kingdom Park at Walt Disney World in Orlando, Florida, on 3 April 2025. Walt Disney has announced a $1bn equity investment in OpenAI, enabling the AI start-up's Sora video generation tool to use its characters. Users of Sora will be able to generate short, user-prompted social videos that draw on more than 200 Disney, Marvel, Pixar and Star Wars characters as part of a three-year licensing agreement between OpenAI and the entertainment giant. A selection of the videos made by users will also be available for streaming on the Disney+ platform. Bob Iger, Disney's CEO, hailed a deal which paired his firm's "iconic stories and characters" with OpenAI's AI technology.

'Architects of AI' named Time Magazine's Person of the Year Time Magazine's Person of the Year for 2025 is not a single person. Instead, the magazine has recognised the year's most influential figure as the architects of artificial intelligence (AI). Nvidia boss Jensen Huang, Meta head Mark Zuckerberg, X owner Elon Musk and AI godmother Fei-Fei Li are among those depicted on one of the magazine's two covers. Experts say it highlights how quickly AI, and the firms behind it, are reshaping society. It comes as a boom in the technology, ushered in by OpenAI's launch of ChatGPT in late 2022, continues at pace.

The Download: solar geoengineering's future, and OpenAI is being sued Solar geoengineering aims to manipulate the climate by bouncing sunlight back into space. In theory, it could ease global warming. But as interest in the idea grows, so do concerns about potential consequences. A startup called Stardust Solutions recently raised a $60 million funding round, the largest known to date for a geoengineering startup. My colleague James Temple has a new story out about the company, and how its emergence is making some researchers nervous. So far, the field has been limited to debates, proposed academic research, and--sure--a few fringe actors to keep an eye on.

GPU prices could follow RAM's big rise Google's Gemini AI comes to Chrome on iPhone and iPad It can summarize pages, create a FAQ on a topic and modify recipes for your dietary needs. After rolling it out on desktop and Android earlier in 2025, Google is finally bringing its built-in Gemini AI experience to iPhone and iPad. It offers new features like summarizing pages and helping you test your knowledge about a subject you're learning. As with any AI tool, though, it shouldn't be trusted for anything important given the possibility of hallucinations and other errors. When it arrives on your iOS device, tapping the spark icon at the left of the address bar (in place of the Google Lens camera) brings up a Pages tool that offers Lens and the new feature, Ask Gemini.

Pine is the Creative Director at TIME. To illustrate the choice of the Architects of AI as TIME's 2025 Person of the Year, we asked two separate artists to help us visualize the incredibly complex technological revolution that is currently underway. London-based illustrator and graphics animator Peter Crowther and digital painter Jason Seiler each created an image that speaks to the duality AI has produced - man vs. machine. Inspired by the inner workings of computer chips, Crowther's intricate AI structure looms large over the busy construction site.

The heirs of an 83-year-old Connecticut mother who was killed by her son in August filed a lawsuit against OpenAI and Microsoft, claiming ChatGPT amplified his "paranoid delusions."

Training large language models (LLMs) typically relies on adaptive optimizers such as Adam, which introduce extra operations and require significant more memory to maintain first- and second-order moments than SGD. While recent works such as GaLore, Fira and APOLLO have proposed state-compressed variants to reduce memory consumption, a fundamental question remains: What are the minimum modifications to plain SGD needed to match state-of-the-art pretraining performance? We systematically investigate this question using a bottom-up approach, and identify two simple yet highly (memory- and compute-) efficient techniques: (1) column-wise gradient normalization (normalizing the gradient along the output dimension), which boosts SGD performance without momentum; and (2) applying first-order momentum only to the output layer, where gradient variance is highest. Combining these two techniques lead to SCALE (Stochastic Column-normAlized Last-layer momEntum), a simple optimizer for memory efficient pretraining. Across multiple LLaMA models (60M-1B), SCALE matches or exceeds the performance of Adam while using only 35-45% of the total memory. It also consistently outperforms memory-efficient optimizers such as GaLore, Fira and APOLLO, making it a strong candidate for large-scale pretraining under memory constraints. For LLaMA 7B model, SCALE outperforms the state-of-the-art memory-efficient methods APOLLO and Muon, in terms of both perplexity and memory consumption.

Prediction of complete step-by-step chemical reaction mechanisms (CRMs) remains a major challenge. Whereas the traditional approaches in CRM tasks rely on expert-driven experiments or costly quantum chemical computations, contemporary deep learning (DL) alternatives ignore key intermediates and mechanistic steps and often suffer from hallucinations. We present DeepMech, an interpretable graph-based DL framework employing atom- and bond-level attention, guided by generalized templates of mechanistic operations (TMOps), to generate CRMs. Trained on our curated ReactMech dataset (~30K CRMs with 100K atom-mapped and mass-balanced elementary steps), DeepMech achieves 98.98+/-0.12% accuracy in predicting elementary steps and 95.94+/-0.21% in complete CRM tasks, besides maintaining high fidelity even in out-of-distribution scenarios as well as in predicting side and/or byproducts. Extension to multistep CRMs relevant to prebiotic chemistry, demonstrates the ability of DeepMech in effectively reconstructing 2 pathways from simple primordial substrates to complex biomolecules such as serine and aldopentose. Attention analysis identifies reactive atoms/bonds in line with chemical intuition, rendering our model interpretable and suitable for reaction design.

\citet{farrell2021deep} establish non-asymptotic high-probability bounds for general deep feedforward neural network (with rectified linear unit activation function) estimators, with \citet[Theorem 1]{farrell2021deep} achieving a suboptimal convergence rate for fully connected feedforward networks. The authors suggest that improved approximation of fully connected networks could yield sharper versions of \citet[Theorem 1]{farrell2021deep} without altering the theoretical framework. By deriving approximation bounds specifically for a narrower fully connected deep neural network, this note demonstrates that \citet[Theorem 1]{farrell2021deep} can be improved to achieve an optimal rate (up to a logarithmic factor). Furthermore, this note briefly shows that deep neural network estimators can mitigate the curse of dimensionality for functions with compositional structure and functions defined on manifolds.

Positional encoding (PE) is a core architectural component of Transformers, yet its impact on the Transformer's generalization and robustness remains unclear. In this work, we provide the first generalization analysis for a single-layer Transformer under in-context regression that explicitly accounts for a completely trainable PE module. Our result shows that PE systematically enlarges the generalization gap. Extending to the adversarial setting, we derive the adversarial Rademacher generalization bound. We find that the gap between models with and without PE is magnified under attack, demonstrating that PE amplifies the vulnerability of models. Our bounds are empirically validated by a simulation study. Together, this work establishes a new framework for understanding the clean and adversarial generalization in ICL with PE.