qiskit-community/ffsim

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Faster simulation of fermionic quantum circuits.

Stars: 108
Forks: 46
Open beginner issues: 0
Indexed issues: 40
Avg merge: 1h 10m
Merged PRs (30d): 9

Dominant language: Python
License: Apache-2.0
Last GitHub push: Sep 15, 2026
Latest indexed: Sep 19, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted

Beginner friendly Everything

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40 open issues indexed

Redundancy in UCJ operator parameterization Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

qiskit-community/ffsim#702 · Opened Aug 27, 2026
Add efficient single-layer UCJ energy Open

qiskit-community/ffsim#683 · 2 comments · 1 assignee · Opened Jul 27, 2026
Number of Givens rotations does not decrease monotonically with increased tolerance Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

qiskit-community/ffsim#672 · 1 reaction · Opened Jul 14, 2026
Add fermionic fast Fourier transform Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

qiskit-community/ffsim#665 · 5 comments · Opened May 3, 2026
Serialization of dataclasses Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

qiskit-community/ffsim#628 · Opened Apr 2, 2026
Regularization spikes in the linear method Open

Difficulty 4/5 3-5 days Newbie friendliness 30/100

qiskit-community/ffsim#552 · 7 comments · Opened Feb 11, 2026
Contraction-based linear operator for unrestricted UCCSD Open

needs upstream change

Difficulty 4/5 3-5 days Newbie friendliness 45/100

qiskit-community/ffsim#549 · Opened Feb 10, 2026
use deploy-pages action for documentation Open

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

qiskit-community/ffsim#509 · Opened Nov 24, 2025
Add how-to guide on orbital optimization Open

documentation

qiskit-community/ffsim#471 · 2 comments · 1 assignee · Opened Sep 16, 2025
Add title and description to metadata of notebooks Open

documentation

qiskit-community/ffsim#468 · 1 assignee · Opened Sep 16, 2025
Add complex-valued unrestricted UCCSD ansatz Open

Difficulty 5/5 Over a week Newbie friendliness 42/100

qiskit-community/ffsim#461 · Opened Sep 12, 2025
Add LUCJ ansatz as parameterized Qiskit circuit Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

qiskit-community/ffsim#411 · Opened Jun 15, 2025
Support spinless Jordan-Wigner transformation Open

Difficulty 3/5 1-2 days Newbie friendliness 42/100

qiskit-community/ffsim#408 · 5 comments · Opened Jun 13, 2025
Implement other protocols for SingleFactorizedHamiltonian Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

qiskit-community/ffsim#406 · Opened Jun 5, 2025
Support greater than 63 orbitals Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

qiskit-community/ffsim#384 · Opened Apr 4, 2025
Make API docs source links go to GitHub Open

documentation

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

qiskit-community/ffsim#360 · Opened Feb 5, 2025
Generate PyO3 stub files automatically? Open

rust

Difficulty 4/5 3-5 days Newbie friendliness 48/100

qiskit-community/ffsim#359 · Opened Feb 3, 2025
Feature Request: Custom Excitation List Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

qiskit-community/ffsim#311 · 1 comment · Opened Aug 22, 2024
Allow configuring custom BLAS Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

qiskit-community/ffsim#291 · Opened Jul 17, 2024
Make functions accept StateVector in addition to Numpy array Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

qiskit-community/ffsim#253 · 2 comments · Opened Jun 23, 2024
Support noisy simulations Open

help wanted needs discussion

Difficulty 5/5 Over a week Newbie friendliness 15/100

qiskit-community/ffsim#244 · Opened Jun 20, 2024
Validation for dataclasses Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

qiskit-community/ffsim#240 · Opened Jun 8, 2024
GivensAnsatzOp from and to orbital rotations should respect real-valuedness Open

Difficulty 4/5 3-5 days Newbie friendliness 20/100

qiskit-community/ffsim#239 · Opened Jun 8, 2024
Move DropNegligible transpiler pass to qiskit Open

Difficulty 4/5 3-5 days Newbie friendliness 15/100

qiskit-community/ffsim#231 · 1 comment · Opened Jun 2, 2024
Parallelize Rust function apply_phase_shift_in_place Open

rust

Difficulty 4/5 3-5 days Newbie friendliness 35/100

qiskit-community/ffsim#230 · 6 comments · Opened Jun 2, 2024
Import SamplerPub directly from qiskit.primitives Open

needs upstream change

Difficulty 1/5 Under an hour Newbie friendliness 35/100

qiskit-community/ffsim#227 · Opened Jun 2, 2024
add specialized code for spinless diag Coulomb Open

Difficulty 4/5 3-5 days Newbie friendliness 42/100

qiskit-community/ffsim#213 · Opened Jun 1, 2024
Implement givens_decomposition in Rust Open

linalg performance rust

Difficulty 5/5 Over a week Newbie friendliness 20/100

qiskit-community/ffsim#197 · Opened May 26, 2024
don't pass conjugates separately in apply_diag_coulomb_evolution_in_place_z_rep Open

Difficulty 3/5 1-2 days Newbie friendliness 30/100

qiskit-community/ffsim#196 · Opened May 26, 2024
add tests for protocols Open

qiskit-community/ffsim#189 · 1 assignee · Opened May 23, 2024
Add more specific type annotations for Numpy arrays Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

qiskit-community/ffsim#178 · Opened May 17, 2024
Add implementation of Estimator primitive to ffsim.qiskit Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

qiskit-community/ffsim#174 · Opened May 14, 2024
nbsphinx can't handle links formatted as code Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

qiskit-community/ffsim#164 · 2 comments · Opened May 5, 2024
Flaky linear algebra test on macOS Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

qiskit-community/ffsim#101 · Opened Feb 13, 2024
Convenient API for spinless fermions Open

qiskit-community/ffsim#87 · 1 assignee · Opened Dec 15, 2023
Add support for returning higher-order RDMs of Slater determinant Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

qiskit-community/ffsim#67 · Opened Oct 30, 2023
Add support for computing 3- and 4-particle RDMs Open

Difficulty 4/5 3-5 days Newbie friendliness 42/100

qiskit-community/ffsim#65 · Opened Oct 30, 2023
Add UCCSD Jastrow ansatz Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

qiskit-community/ffsim#53 · Opened Oct 20, 2023
Use zrot for applying Givens rotation Open

needs upstream change performance rust

qiskit-community/ffsim#28 · 1 comment · 1 assignee · Opened Sep 22, 2023
Support multiple data types in Rust functions Open

rust

Difficulty 5/5 Over a week Newbie friendliness 20/100

qiskit-community/ffsim#14 · Opened Sep 20, 2023

qiskit-community/ffsim

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