Modern science is built on collaboration. The most pressing challenges - whether in energy, health or technology - rarely fit neatly within a single discipline, requiring researchers to work across fields to generate new ideas and solutions. That spirit of collaboration also can cross international borders, accelerating discovery.

In that same vein, three Japanese graduate students funded by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) participated in a five-week research program in early 2026 at the U.S. Department of Energy's (DOE) Argonne National Laboratory. The visit was part of a larger exchange program that began at DOE's Oak Ridge National Laboratory in Tennessee and continued at Argonne, where the students worked with mentors who conduct research in scientific computing.

Masahiko Gen, who hails from the city of Tsukuba, was eager to participate in the program along with fellow graduate students Ryoji Himeno and Shunya Uda. Gen said it was a rare opportunity to participate in a pilot program between Japan and two of DOE's largest Office of Science laboratories.

At Argonne, Gen worked on incorporating a method - developed by his doctoral advisor in Japan, Professor Minoru Otani - into a software package for density functional theory (DFT). DFT is a quantum-mechanical modeling method used to calculate the electronic structure of atoms, molecules and solids.

Gen incorporated a method called the Effective Screening Medium (ESM) to more accurately treat electrostatic potentials, especially for surface and interface systems in DFT calculations. Electrostatic potential influences how electrons behave in a material, making it especially important for studying energy technologies such as fuel cells and catalysts, where surfaces and interfaces are often electrically charged or electronically imbalanced. With the ESM method, he simulated such systems more realistically within the DFT framework.

"I learned how to implement the method efficiently, how to validate its correctness and what types of materials are suitable for its application," Gen said. ​"My mentors are not necessarily specialists in this specific method, but they are experts in materials science and DFT calculations. They provided valuable advice on implementation and asked insightful questions at appropriate times, which helped me deepen my understanding."

Argonne Computational Scientist Alvaro Vazquez-Mayagoitia served as Gen's mentor. Computational Scientist Noah Paulson and Nanotechnology Scientist Jie Xu, who holds a joint appointment as an assistant professor at the University of Chicago, mentored Himeno. Assistant Computational Scientist Riccardo Balin and Computer Scientist Bethany Lusch served as mentors for Uda.

By providing the Japanese students an opportunity to engage in hands-on research in world-class labs, the program demonstrated potential of fostering new collaborations and encouraging talent development through strategic international partnership.

It was the first time Paulson had worked with doctoral students from another country, and he believes international collaboration offers great value.

"If you just stay in your community and your country, you're going to be limiting yourself in terms of the type of things you're going to be learning and the processes that you know about and follow," he said. ​"So, this sort of program is important for exposing both of us to different ways of doing research, and I think it will strengthen both of our research programs."

Argonne has become a destination for cross-border innovation and has a long relationship with the scientific community in Japan. DOE's Office of Science worked with MEXT as well as Oak Ridge and Argonne to pilot the program, a result of the memorandum of understanding MEXT and DOE signed in April 2024.

Valerie Taylor, director of Argonne's Mathematics and Computer Science division, is the DOE Advanced Scientific Computing Research program point of contact on DOE-MEXT collaborations along with Jeff Vetter at Oak Ridge.

"Argonne continues to be dedicated to building a workforce that is agile, future-ready and prepared to lead in the science of tomorrow," Taylor said. ​"Through strategic STEM partnerships, hands-on internships like MEXT and collaborative workforce ecosystems, Argonne is cultivating talent pipelines that drive innovation."