ffsim: Faster simulation of fermionic quantum circuits
Abstract
We present ffsim, an open-source software library for fast simulation of fermionic quantum circuits. ffsim exploits conservation of particle number and the z component of spin, symmetries present in a wide range of fermionic systems, to dramatically reduce memory usage and simulation time compared to general-purpose quantum circuit simulators. Compared to FQE, a library with similar functionality, ffsim differs in software design and is faster on a representative set of simulation benchmarks. Beyond state vector evolution by basic fermionic gates, ffsim offers a number of additional features including variational ansatzes, Hamiltonian time evolution via Trotter-Suzuki product formulas, efficient sampling of Slater determinants, seamless integration with Qiskit and PySCF, and comprehensive documentation. We demonstrate ffsim's capabilities on scientific applications involving quantum circuits of up to 64 qubits.
Cite
@article{arxiv.2605.03123,
title = {ffsim: Faster simulation of fermionic quantum circuits},
author = {Kevin J. Sung and Inho Choi and Mirko Amico and Bartholomew Andrews and Esra Ayantuna and Yukio Kawashima and Wan-Hsuan Lin and David Omanovic and Samuele Piccinelli and Javier Robledo Moreno and Abdullah Ash Saki and James Shee and Soyoung Shin and Minh C. Tran and Kento Ueda and Haimeng Zhang and Mario Motta},
journal= {arXiv preprint arXiv:2605.03123},
year = {2026}
}
Comments
24 pages, 4 figures