Ffsim

What's Changed
* add support for acting on just one spin sector by kevinsung in https://github.com/qiskit-community/ffsim/pull/91


**Full Changelog**: https://github.com/qiskit-community/ffsim/compare/v0.0.18...v0.0.19

What's Changed
* add on-site number-number interaction gate by kevinsung in https://github.com/qiskit-community/ffsim/pull/86
* Return lower ranks of RDMs by kevinsung in https://github.com/qiskit-community/ffsim/pull/88
* Add linear method for optimization of variational wavefunction by kevinsung in https://github.com/qiskit-community/ffsim/pull/89


**Full Changelog**: https://github.com/qiskit-community/ffsim/compare/v0.0.17...v0.0.18

What's Changed
* Add final orbital rotation to hop gate ansatz by kevinsung in https://github.com/qiskit-community/ffsim/pull/85

Breaking Changes
* Parameter ordering of UCJAnsatz has changed. See 85 .

**Full Changelog**: https://github.com/qiskit-community/ffsim/compare/v0.0.16...v0.0.17

What's Changed
* add real-valued ucj operator by kevinsung in https://github.com/qiskit-community/ffsim/pull/77
* add functions and tests for random two-body tensors by kevinsung in https://github.com/qiskit-community/ffsim/pull/79
* add orbital rotation for molecular hamiltonian by kevinsung in https://github.com/qiskit-community/ffsim/pull/80


**Full Changelog**: https://github.com/qiskit-community/ffsim/compare/v0.0.15...v0.0.16

What's Changed
* add single-factorized hamiltonian by kevinsung in https://github.com/qiskit-community/ffsim/pull/76
* performance improvements from using standard library math functions instead of numpy functions


**Full Changelog**: https://github.com/qiskit-community/ffsim/compare/v0.0.14...v0.0.15

What's Changed
* use fast contract_2e from pyscf by kevinsung in https://github.com/qiskit-community/ffsim/pull/70
* implement linear operator protocol for df hamiltonian by kevinsung in https://github.com/qiskit-community/ffsim/pull/73


**Full Changelog**: https://github.com/qiskit-community/ffsim/compare/v0.0.13...v0.0.14