Benchmark

Quantum-Centric Chemistry Beyond Exact Diagonalization (IBM Heron + Fugaku)

Sample-based quantum diagonalization (SQD) with classical supercomputer post-processing · Chemistry · 77 qubits · Qiskit + ffsim + custom SQD pipeline

Quantum-centric supercomputing benchmark coupling an IBM Heron quantum processor with the Fugaku classical supercomputer to compute ground-state electronic structure of molecules beyond what exact diagonalization can reach: N2 dissociation and [2Fe-2S] and [4Fe-4S] iron–sulfur clusters. Circuits used up to 77 qubits and 10,570 two-qubit gates; the classical side applied sample-based quantum diagonalization to project noisy quantum samples onto chemically meaningful subspaces. This is one of the first end-to-end benchmarks of the quantum-centric-supercomputing architecture on a real chemistry target set.

chemistrySQDIBM-HeronFugakuiron-sulfurN2quantum-centric-supercomputing

Quantum-centric supercomputing benchmark coupling an IBM Heron quantum processor with the Fugaku classical supercomputer to compute ground-state electronic structure of molecules beyond what exact diagonalization can reach: N2 dissociation and [2Fe-2S] and [4Fe-4S] iron–sulfur clusters. Circuits used up to 77 qubits and 10,570 two-qubit gates; the classical side applied sample-based quantum diagonalization to project noisy quantum samples onto chemically meaningful subspaces. This is one of the first end-to-end benchmarks of the quantum-centric-supercomputing architecture on a real chemistry target set.

Key Metrics
Qubits used
77
Two-qubit gates
10,570
Molecules
N2, [2Fe-2S], [4Fe-4S]
Classical partner
Fugaku supercomputer
Method
Sample-based quantum diagonalization
Why It Matters

Extends quantum chemistry benchmarks past the exact-diagonalization frontier onto iron–sulfur clusters — a biologically relevant, historically hard target — inside a credible quantum-classical workflow.

Hardware

IBM Heron superconducting processor + RIKEN Fugaku supercomputer

Framework

Qiskit + ffsim + custom SQD pipeline