William Allan Bardeen (September 15, 1941 – November 18, 2025) was an American theoretical physicist who worked at the Fermi National Accelerator Laboratory. He is renowned for his foundational work on the chiral anomaly (the Adler-Bardeen theorem), the Yang-Mills and gravitational anomalies, the development of quantum chromodynamics and the Λ M S ¯ {\displaystyle \Lambda _{\overline {MS}}} scheme frequently used in perturbative analysis of experimentally observable processes such as deep inelastic scattering, high energy collisions and flavor changing processes. Bardeen also played a major role in developing a theory of dynamical breaking of electroweak symmetry via top quark condensates, leading to the first composite Higgs models. His work on the chiral symmetry breaking dynamics of heavy-light quark bound states correctly predicted abnormally long-lived resonances which are chiral symmetry partners of the ground states, such as the D s ∗ ( 2317 ) {\displaystyle D_{s}^{*}(2317)} . He also developed an analytic, non-perturbative approach for the calculation of non-leptonic decays of Kaons, known as Dual QCD. He was considered one of the world's leading authorities on quantum field theory in its application to real-world physical phenomena.
Background Bardeen was born in Washington, Pennsylvania, on September 15, 1941, the son of physicist John Bardeen and Jane Maxwell Bardeen. The family relocated to Champaign-Urbana, Illinois in 1951, where Bardeen attended the University High School. Bardeen met his future wife, Marge, in high school chemistry class. After graduating from Cornell University in 1962, Bardeen earned his Ph.D. degree in physics from the University of Minnesota in 1968. Steve Gasiorowicz was his thesis advisor. Following research appointments at Stony Brook University and the Institute for Advanced Study in Princeton, he was an associate professor in the physics department at Stanford University. In 1975, Bardeen joined the staff of the Fermi National Accelerator Laboratory where he served as Head of the Theoretical Physics Department from 1987-1993 and 1994-1996. From 1993-1994, he was Head of Theoretical Physics at the SSC Laboratory before the project was terminated by act of Congress. Bardeen lived in Warrenville, Illinois, with his wife Marge, who was manager of the Education Office at Fermilab. He had two grown children: Charles, a retired Project Scientist at the National Center for Atmospheric Research, Boulder, CO, and Karen, who taught chemistry at Oak Park and River Forest High School, Oak Park, Illinois. Bardeen died at his home in Warrenville, Illinois, on November 18, 2025, at the age of 84.
… excerpt ends here. Continue reading the full article.
