OUR RESEARCH

Sunshine Balingit started in Livermore Computing (LC) as an HPC Cluster Academy intern and joined the Laboratory in 2020 after earning her bachelor of science degree in computer science from California State University, East Bay. In her current roles as LC’s Information System Security Officer (ISSO) and Cybersecurity System Administrator, Sunshine manages security plans, completes assessments and reauthorizations and validates that LC systems are compliant with existing policies. She says, “I have to understand how LC works as a whole to ensure that the services we are managing and any ideas we implement can be executed in a safe way.”

To further improve LC’s cybersecurity posture, she is leading a project to automate the process of verifying LC’s systems are correctly implementing the TOSS (Tri-Lab Operating System) STIG (Stack Security Technical Implementation Guide). This work includes accounting for any adjustments that have to be made for HPC systems as policies are typically written with much smaller systems, such as laptops, in mind. She is also helping to establish the STIG for the upcoming TOSS 5.0 environment.

Outside the Laboratory, Sunshine expands her skill set through initiatives like SCinet and recruitment activities at her alma mater. She says, “Participating in activities like these allows me share what I know to help others, learn about what people are doing elsewhere and apply insights to see what we could do better."

Yohann Dudouit wrote his first finite element simulation as an undergraduate student — creating a video game physics engine involving complex meshing, discretizing, problem solving and visualization — in just three months. This project was the genesis of a career focused on developing generalized mathematical libraries for simulating complex physical phenomena.

After earning his Ph.D. from the University of Bordeaux, Yohann joined the Laboratory as a postdoc in 2017. Working with the MFEM team on CEED (Center for Efficient Exascale Discretizations), he gained insight into mapping abstract mathematics to physical hardware, memory hierarchy and the critical metrics for optimizing performance on GPU architectures. He applied this expertise to the Laboratory’s BLAST project, extending matrix-free approaches to discontinuous Galerkin methods and adaptive mesh refinement, and later implemented those same performance-optimization techniques for the GEOS project.

As part of the Laboratory’s Center for Applied Scientific Computing, Yohann continues work on high-dimensional applications, from transport and kinetic simulations to space-time discretizations, using matrix-free, high-order and GPU-accelerated finite element methods. Since 2024, he’s led an LDRD project to implement these methods for inertial confinement fusion simulations. He is also exploring ways to bridge formal methods with applied mathematics to produce provably correct numerical simulation software.

Stefanie Guenther appreciates the application-driven aspect of the research at LLNL. “I enjoy seeing my work being used for larger project goals and enabling exciting, innovative technologies,” she says.

Stefanie’s current research is in optimal control and optimization methods that are deployed efficiently on HPC machines. She is focused mainly on optimal quantum control, which aims to reduce errors of logical operations on Livermore’s quantum computing testbed, QuDIT. Stefanie is motivated by the direct impact her work has on this specific Lab application but also more broadly for the quantum science community.

The draw of advanced technology is complemented by the collaborative environment at LLNL, where continuous learning and knowledge exchange thrive. “Working at LLNL exposes you to many different advanced research technologies,” Stefanie says. “It is an excellent place to constantly learn new things and contribute new findings within your area of expertise. People here are similarly eager to learn from you, meaning that your knowledge and viewpoints are valued and appreciated.”

Stefanie joined the Lab as a postdoc in 2019, after a three-month appointment as a visiting researcher during her Ph.D. studies at Rheinisch-Westfälische Technische Hochschule Aachen University, in Germany.

Nisha Mulakken is one of a growing number of “boomerang” employees — she left the Lab to work in industry and returned several years later, drawn back by the Lab’s strong mission focus and real-world applications that improve society and human life.

Today, Nisha is both a line manager and a project leader supporting several biosecurity projects, mostly focused on designing assays for pathogen detection, a skill she learned entirely on the job. In a recent project, Nisha designed a system, Meta2DB, for showcasing curated metagenomic data and standardized metadata from over 10,000 samples processed through LLNL’s metagenomic classification pipeline. The system, once released to the public, will enable researchers to compare microbiome features and their impact on multiple human diseases across diverse study designs in a way that is near impossible to do currently. Unique analysis tools, including sophisticated machine learning models developed at LLNL, will also be available for download.

“LLNL has provided me with opportunities to get involved with exciting new technical areas and to grow my skills in a nurturing, collaborative environment,” Nisha says. “Every year, I take on projects that are different from things I’ve done before. I can work on the same team for a long time without ever getting bored.”

Dr. Jayson “Luc” Peterson is the associate program leader for data science, within the Space Science and Security Program at Lawrence Livermore National Laboratory, where he is responsible for the leadership and development of LLNL’s broad portfolio of projects at the intersection of data science and outer space.

He joined LLNL in 2011 as a member of the inertial confinement fusion program at the National Ignition Facility and was part of the team that first achieved ignition and net energy gain from nuclear fusion in December 2022. At LLNL he has worked across several programs, from inertial confinement fusion and stockpile stewardship to COVID-19 pandemic response and space science and security.

His technical contributions in these areas span hydrodynamics, radiation transport, modeling and simulation (mod/sim), experimental design, digital engineering, uncertainty quantification, verification and validation, data analytics, high-frequency and high-performance computing and machine learning. He currently leads the ICECap project, which aims to bring machine learning-enhanced digital design to exascale supercomputers.

Luc holds doctorate and master’s degrees in Astrophysical Sciences (Plasma Physics) from Princeton University and a bachelor’s degree in physics and science, technology and society from Vassar College.

Luc’s hobbies include spending time camping, hiking, Airstreaming, gaming, ferrying around his children, long distance running, cooking, playing softball and volunteering with his church and participating in a book club he began over 15 years ago. Occasionally, he finds time to sleep.

Rob Rieben was hooked after visiting the Laboratory during a summer institute while a physics undergrad at the University of California, Riverside. He joined Lawrence Livermore as a graduate research fellow in 2000 and progressed to a postdoctoral research position after earning his Ph.D. “You will never be bored or run out of new and exciting things to learn and apply when working here. This is truly a place where team-based ‘big science’ happens every day,” he says.  

A computational physicist by training, Rob now leads a large multi-physics code project in the Weapons Simulation and Computing program. He recently won a Gold Award from the Strategic Deterrence Principal Directorate for sustained contributions in advancing next-generation simulation and computing.   

Between applying state-of-the-art computation and numerical methods, having access to some of the world’s most powerful high-performance computing platforms and collaborating with some of the best minds in the field, Rob is excited to face the next challenges his work may bring. “What keeps me here is the never-ending set of interesting problems to solve and the constant learning and collaborative team-based scientific work required to solve them,” he says.   

Rob holds a Ph.D. in engineering/applied science from the University of California, Davis and B.S. in physics from the University of California, Riverside.