Two UC Irvine professors, Juan Pedro Ochoa-Ricoux and James Owen Weatherall, have been elected as fellows by the American Physical Society (APS), an honor granted to physicists who have made exceptional contributions to the field.

Juan Pedro Ochoa-Ricoux, a UC Irvine professor of physics and astronomy, was recommended by the APS’s Division of Particles and Fields. His recognition is for leadership in precision neutrino oscillation measurements and key contributions to the Daya Bay, JUNO, and DUNE experiments, which advance next-generation neutrino physics.

Earlier in his career, as a postdoctoral scholar at Lawrence Berkeley National Laboratory, Ochoa-Ricoux worked on the Daya Bay experiment. This project involved eight detectors observing neutrino emissions from six nuclear reactors in China. The experiment demonstrated that the value of theta-13, a parameter governing neutrino oscillations, was not zero—a "discovery with big implications for our field," as stated by Ochoa-Ricoux.

In 2014, Ochoa-Ricoux joined the JUNO project, which also detects neutrinos from nuclear reactors in China, though with a much larger detector. JUNO scientists have provided precise measurements of three neutrino oscillation parameters globally and indicated how neutrino masses are ordered. Ochoa-Ricoux was one of two individuals responsible for coordinating the production of these results.

Ochoa-Ricoux continues his work on the JUNO project and has also joined DUNE, a U.S.-based particle physics experiment. In this project, a powerful neutrino beam will be sent underground from Fermilab, near Chicago, to a former mine in South Dakota. DUNE’s detector is designed to produce detailed, three-dimensional images of neutrino interactions. Ochoa-Ricoux expressed that being named a fellow felt wonderful, noting his humility in contributing to advancing the frontiers of knowledge in physics.

James Owen Weatherall, Chancellor’s Professor and department chair of logic and philosophy of science at UC Irvine, was chosen as an APS fellow by his peers in the society’s Forum on History & Philosophy of Physics. He was recognized for substantial contributions to the foundations of classical field theories and the philosophy of physics, distinguished mentorship, leadership, and service to the discipline, and for conveying physics to broad public audiences through acclaimed books, according to the society.

As a philosopher of physics, science, and mathematics, Weatherall's work focuses on gravitation, cosmology, and the concepts underlying scientific theory development. He has provided important analyses to clarify the structure of space-time theories and resolve conceptual puzzles in general relativity, Yang-Mills theory, and the philosophy of modern physics.

Weatherall is the author or coauthor of three books: *The Physics of Wall Street: A Brief History of Predicting the Unpredictable*, *Void: The Strange Physics of Nothing*, and *The Misinformation Age: How False Beliefs Spread*, coauthored with Cailin O’Connor. He has published over 70 research articles and book chapters in journals across the philosophy of science, physics, and mathematics.

His current research addresses foundational questions in classical and quantum field theories, the philosophy of cosmology, and emerging philosophical issues related to artificial intelligence in science and society. He is also writing a scientific biography on John von Neumann, a prominent 20th-century mathematician. This past year, Weatherall was elected to the American Academy of Arts and Sciences.

Weatherall conveyed his pleasure and gratitude for the honor, noting the significance of the APS Forum on History & Philosophy of Physics having changed its name to include philosophy and beginning to elect fellows in recognition of work in this area. He expressed pride in being among the first selected since that change.

Ochoa-Ricoux and Weatherall are among 153 scientists from around the country inducted into this year’s cohort of American Physical Society fellows.