IBM Qiskit SDK v2.2 Finalizes C API for Quantum-HPC Integration

October 20, 2025

Details

  • IBM has released Qiskit SDK v2.2, adding a transpiler function to its C API, making it possible to create end-to-end quantum-centric supercomputing workflows entirely in compiled languages such as C++ and Fortran on high-performance computing systems.
  • This update completes a sequential rollout: Qiskit v2.0 (March 2025) introduced the C API with observables, v2.1 brought circuit construction with up to 20x speed increases, and v2.2 now delivers full transpilation, supporting all stages of quantum workflows—mapping, optimization, execution, and post-processing on HPC platforms.
  • IBM demonstrated the new capabilities by running a sample-based quantum diagonalization (SQD) algorithm to simulate the ground state energy of the Fe₄S₄ molecule, a biologically significant iron-sulfide cluster. The workflow, built in C++17, utilizes OpenMP and MPI for parallelism and incorporates RIKEN's SBD eigensolver.
  • The SQD addon for Qiskit HPC compiles into a single binary, supporting standard HPC job launchers like mpiexec and mpirun. It runs on Linux, macOS, and Windows across x86_64 and ARMv8 systems, designed to function reliably even in restricted modes with exceptions and RTTI disabled for optimal performance.
  • By targeting seamless quantum-classical integration, IBM is lowering barriers for quantum chemistry and scientific computing teams. Researchers can now add quantum routines directly to C++ or Fortran codebases—without Python rewrites—easing adoption for those working in parallel, multi-node computing environments as IBM pushes toward quantum advantage by 2026.

Impact

IBM’s finished Qiskit C API empowers scientists to natively embed quantum computing into classical supercomputing workflows using well-established compiled languages and parallel processing tools. This move helps overcome prior obstacles posed by Python’s limitations in HPC, accelerating quantum adoption for computational chemistry and materials science. With this release, IBM solidifies its roadmap toward demonstrating quantum advantage by 2026 and strengthens its competitive positioning in the race for practical quantum utility.

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