Julien is an Assistant Professor in the Division of Public Policy at the Hong Kong University of Science and Technology. His research focuses on how technology interplays with society and international security through various topics such as nuclear technologies, energy transition, and technological risks, specifically in the Asia Pacific region and in the context of the U.S-China rivalry. A nuclear engineer by training, Julien has also worked to promote open-source and transparent scientific tools that can contribute to research in nuclear security and nuclear technologies. He is the project lead for the open-source nuclear reactor physics code ONIX (https://onix-documentation.readthedocs.io/en/latest/).
Julien was a postdoctoral fellow at the Project on Managing the Atom at Harvard’s Belfer Center from 2021 to 2022 and a nuclear security postdoctoral fellow at Stanford's Center for International Security and Cooperation (CISAC) from 2019 to 2021. He was also part of the Science and Global Security research team at Princeton University from 2014 to 2019 and regularly contributes to projects with the International Panel on Fissile Materials (IPFM). Julien holds a Ph.D. in Applied Physics from Princeton University, an M.Sc. in Nuclear Science and Technology from Tsinghua University Beijing, and a Diplôme d'Ingénieur (M.Sc. and B.Sc.Eng.) from Ecole Centrale de Marseille.