JuliaCon 2026

Lattice Quantum Chromodynamics (Lattice QCD) is a first-principles approach to strongly interacting gauge theories and requires large-scale high-performance computing. Production codes in this field have traditionally been written in C, C++, or Fortran.
JuliaQCD is a Lattice QCD simulation framework written entirely in Julia, developed to explore whether a high-level language can support both rapid development and large-scale HPC simulations. The framework provides distributed-memory parallelism via MPI and achieves competitive performance on modern CPUs and GPUs while keeping lattice field operations and data structures modular and expressive through multiple dispatch.
In our recent work [1], we extend JuliaQCD by introducing compiler-level reverse-mode automatic differentiation for the first time. Using LLVM-based AD, Hybrid Monte Carlo (HMC) force terms are generated directly from the action code, removing the need for separately derived and manually maintained force implementations. We validate the correctness of the automatically generated forces and examine their performance relative to conventional hand-written implementations.
This work demonstrates how Julia can support both conventional HPC-style implementations and more modern compiler-based techniques within a single, coherent framework for large-scale scientific computing.
[1] Yuki Nagai, Akio Tomiya, Hiroshi Ohno, "Lattice Gauge Theory via LLVM-Level Automatic Differentiation", arXiv:2602.20516