Thomas Appelquist received his Ph.D. in theoretical particle physics from Cornell University in 1968. From 1968 until 1970, he held a postdoctoral appointment at the Stanford Linear Accelerator Center at Stanford University. In 1970, he joined the faculty at Harvard University. In 1975, he moved to Yale and was appointed Professor of Physics in 1976. From 1983 until 1989, he served as Chairman of the Yale Department of Physics. He served as Director of the Division of Physical Sciences and Engineering from 1990 to 1993. In 1991, he was named Eugene Higgins Professor of Physics, and from 1993 to 1998 he served as Dean of the Graduate School.
He is a Fellow of the American Physical Society, the recipient of a Senior U.S. Scientist award from the Alexander von Humboldt Foundation, and a Fellow of the American Academy of Arts and Sciences. In 1997, he was awarded the J.J. Sakurai Prize of the American Physical Society.
From 1993 to 1996, he served as President of the Aspen Center for Physics. He has served on many advisory committees for the National Science Foundation, the Department of Energy and the American Physical Society. From 1989 to 1993, he was a member of the Scientific Policy Committee of the Superconducting Supercollider (SSC) Laboratory. At Yale, during the 1992-1993 academic year, he served on the faculty/trustee Presidential Search Committee. From 1999-2001, he chaired the committee of the National Research Council that prepared an Overview of the field of physics as the culmination of the NRC survey “Physics in a New Era”. He currently serves as Chairman of the Board of the Aspen Center for Physics.
His research has focused on the theory of elementary particles, including the strong interactions and electroweak unification. Among his contributions are his work predicting the existence of the J/Y particle (charmonium), the formulation of the decoupling theorem in quantum field theory, the study of quantum effects in Kaluza-Klein theories, the development of the electroweak chiral lagrangian, the proposal of walking technicolor theories, and the idea of universal extra dimensions in which all the particles of the standard model access new spatial dimensions at accessible energies.