Gates and ansatze
| Component | Description | Learn more |
|---|---|---|
su2_equivariant_2_qubit_gate | The unique 2-qubit SU(2)-equivariant primitive gate: phases the singlet sector and leaves the triplet sector unchanged. | Guide · Reference |
su2_equivariant_3_qubit_gate | The exact 3-qubit SU(2)-equivariant gate; four angles parameterize the allowed mixing between the two spin-1/2 copies. | Guide · Reference |
su2_equivariant_ansatz | Parameterized spin-symmetry-preserving ansatz built from the 2-qubit primitive; supports brickwork, linear, and custom pair layouts. | Guide · Reference |
Symmetry and verification helpers
| Component | Description | Learn more |
|---|---|---|
is_su2_equivariant | Check whether a dense unitary commutes with all three global spin generators. | Guide · Reference |
spin_generators | Dense global spin generators (S_x, S_y, S_z) for diagnostics and symmetry-aware observables. | Guide · Reference |
total_spin_ops | Dense total spin operators (S^2, S_z). | Guide · Reference |
brickwork_pattern | Nearest-neighbor even-then-odd qubit pair layout used by the brickwork ansatz. | Guide · Reference |
Variational solvers
| Solver | Description | Learn more |
|---|---|---|
haiqu.variational_optimization | Minimize an observable expectation value, or a nonlinear objective over several observables, for a parameterized ansatz using NFT or SciPy optimizers. | Guide · Reference |
haiqu.pretrain | Pretrain ansatz parameters against the problem objective to warm-start a variational optimization. | Reference |
haiqu.su2_equivariant_compilation | Fit a shallow brickwork circuit of 2-qubit SU(2)-equivariant gates to an equivariant target unitary. | Guide · Reference |