in 1981, he became a research physicist at fermilab in illinois. in joint work with james bjorken, an american theoretical physicist who is emeritus professor at the stanford linear accelerator center, he developed a theory of "intrabeam scattering" in particle accelerators. for this work, he was awarded the 2017 robert e. wilson prize for achievement in the physics of particle accelerators, since that theory ""empowered major discoveries in a broad range of disciplines by a wide variety of accelerators, including hadron colliders, damping rings/linear colliders, and low emittance synchrotron light sources.""