Google Chief Scientist Jeff Dean Leaves to Start Discovery Loop AI

Jeff Dean, Google's chief scientist and one of the architects behind the company's dominance in search and AI, is leaving after 27 years to start an AI company called Discovery Loop.

Dean announced Wednesday that three other longtime Google colleagues are joining him: Sanjay Ghemawat, Oriol Vinyals, and Quoc Le. The four worked together on the Google Brain team and core infrastructure that underpins much of modern AI.

Discovery Loop, structured as a public benefit corporation, aims to automate scientific and engineering experiments. The goal is to let machines propose, run, and evaluate experiments in parallel, freeing researchers from repetitive work. Dean wrote on X that the company wants to tackle 14 grand challenges originally laid out by the National Academy of Engineering, topics ranging from reverse-engineering the brain to preventing nuclear terror.

"We're building AI to run experiments at unprecedented scale and to solve the biggest bottlenecks in science and engineering," Dean wrote.

Radical Ventures and Khosla Ventures led the initial funding round. Lightspeed, Kleiner Perkins, and Doerr Capital also participated, according to Dean. Alphabet is a founding investor and cloud partner, Google CEO Sundar Pichai said.

Dean's tenure at Google started in 1999, when he was the company's 30th employee. He helped build Google Search, Google News, Google Translate, Google Ads, and co-founded the Google Brain team. His work on the Tensor Processing Unit (TPU) is credited with accelerating AI research across the industry. Later, he co-led development of Gemini, Google's family of models.

Ghemawat, who Dean's children call "Uncle Sanjay" according to a 2018 New Yorker profile, worked with Dean at Digital Equipment Corporation before both joined Google. They became the company's first-ever Senior Fellows at level 11. Dean's pitch deck lists him as the most-cited distributed systems researcher and Ghemawat as the fourth.

Vinyals, a principal scientist at Google DeepMind, focused on machine learning and reinforcement learning. His AlphaStar project produced an agent that beat a top-tier professional StarCraft II player. Dean lists him as the sixth most-cited AI researcher.

Le, a founding member of the Google Brain team, worked under Stanford's Andrew Ng. One of his early projects built a neural network across 1,000 machines with 16,000 processors that taught itself to recognize cats after training on 10 million YouTube video frames, as The New York Times reported in 2012.

Google has seen a stream of AI talent leave in recent years. In 2023, the company merged its Brain and DeepMind research groups under Demis Hassabis. With Dean's departure, Hassabis becomes chair of Google DeepMind and chief scientist of Alphabet. Koray Kavukcuoglu, previously CTO of Google DeepMind, takes over day-to-day operations of the unit as senior vice president.