About
Teams > CERN IT members
Staff
Stefan Roiser
Stefan Roiser is a senior computing engineer in CERN’s IT department, where he leads a team of physicists and engineers working on improving the performance of HEP software applications, especially Monte Carlo event generators. He earned his PhD at TU Wien with a dissertation on event data modelling for the LHCb experiment. He then went on to work on various software projects at CERN, such as Gaudi, SEAL and ROOT, and to hold major software and computing management roles, including LHCb Computing Coordinator. His interests are in data processing software frameworks and their evolution alongside changing hardware, with a recent focus on software engineering for compute accelerators. He is also active in training, particularly organizing events on programming languages, and works mainly in C++, CUDA/HIP, Python and, most recently, Fortran.
Enrico Bothmann
Enrico Bothmann graduated from the University of Göttingen in 2016. From 2016–2018 he has been a postdoc at the Higgs Center for Theoretical Physics at the University of Edinburgh. From 2018–2024, he returned to Göttingen for a second postdoc. As of January 2025, he has joined CERN-IT to work on performance improvements of event generators. Enrico is a core Sherpa developer, and leads the Pepper project. His interests cover perturbative QCD and EW calculations, hardware acceleration through CPU vector instructions and GPU offloading, uncertainty estimations using reweighting techniques, and Machine Learning applications to improve Monte Carlo efficiencies.
Enrico is a member of the MCnet collaboration board.
Fellows
Daniele Massaro
Daniele Massaro got his PhD degree in 2024 after a join PhD with the University of Bologna and the Université Catholique de Louvain. Since June 2024, he joined the IT department at CERN to work on hardware acceleration of the Monte Carlo event generator MadGraph. Daniele’s main interest is in the interplay between physics and software engineering. His research activity covers Monte Carlo simulations, hardware acceleration through GPU or vector CPU, performance software engineering and profiling.
PhD students
Frantisek Stloukal (joint with Sorbonne and LIP6)
František Stloukal is a PhD student at CERN, Sorbonne University and LIP6, working on computer arithmetic and numerical analysis for Monte Carlo event generators. He studied applied mathematics at the Czech Technical University in Prague and the Hong Kong University of Science and Technology. He was a CERN Summer Student, within the CMS collaboration. His previous research focused on computational fluid dynamics, including 1- and 3-dimensional numerical methods, FVM and FEM, and GPU-accelerated implementations of lattice Boltzmann and Direct Simulation Monte Carlo methods for non-continuum flows. He has also worked in industry on computational problems ranging from SMRs and automotive thermal management to rarefied gas dynamics for high-precision lithography optics.
His current research focuses on improving the numerical robustness and performance of Monte Carlo event generators through well-conditioned algorithms, mixed-precision techniques, and numerical emulation libraries. His work is primarily centred on MadGraph, with an emphasis on reliable floating-point computation and the numerical stability of high-energy physics calculations.
Yann Zurstrassen (joint with UCL)
Yann is a PhD student at UCL and CERN working on the Pepper event generator as part of MCnet. His research focuses on the virtual (one-loop) corrections in Pepper, aiming at fast and efficient next-to-leading-order calculations that can run on modern hardware, including GPUs. He completed his undergraduate degree in Natural Sciences at UCL, followed by an MPhil in Data Intensive Science at the University of Cambridge.
Former members
- Zenny Wettersten