Ermal Rrapaj
Computer Systems Engineer 3
National Energy Research Scientific Computing Center (NERSC)
HPC Technology Dept.
Advanced Technologies Group
Ermal Rrapaj is a staff member of the Advanced Technologies Group (ATG) in computational research at Berkeley Lab. Prior to joining ATG, Ermal was a Riken-Berkeley fellow and N3AS fellow. He has earned masters in Applied Mathematics and Physics and a Ph.D. in Physics from the University of Washington, Seattle. He is a visiting researcher at the University of California Berkeley Physics Department and Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS) RIKEN. Rrapaj's research at NERSC explores the intersection of scientific computing algorithms and HPC system architecture. I have a background in developing, implementing, and optimizing new algorithms for ab initio quantum many-body physics, with a focus on nuclear astrophysics. My postdoctoral work investigated Monte Carlo, deep learning, and quantum computing methods. Rrapaj's work in HPC centers on the power profile of applications, supporting deep learning methods for science, and integrating quantum computing software and hardware for scientific domains.
Recent Publications
Collective neutrino oscillations in three flavors on qubit and qutrit processors
Authors: Spagnoli, L; Goss, N; Roggero, A; Rrapaj, E; Cervia, MJ; Patwardhan, AV
May 2025, Physical Review D
HATT: Hamiltonian Adaptive Ternary Tree for Optimizing Fermion-to-Qubit Mapping
Authors: Liu, Y; Yao, K; Hong, J; Froustey, J; Rrapaj, E; Iancull, C
March 2025, IEEE Symposium on High-Performance Computer Architecture (HPCA)
Classical optimization with imaginary-time block encoding on quantum computers: The MaxCut problem
Authors: Zhong, D; Francis, A; Rrapaj, E
October 2025, Physical Review A (PRA)
A Global Perspective on Supercomputer Power Provisioning: Case Studies from United States and Europe
Authors: Patki, T; Rountree, B; Wilde, T; Bartolini, A; Brink, S; Heiskanen, E
June 2025
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