rqutils.paulis.general.l0_projector

rqutils.paulis.general.l0_projector(reduced_dim: int, original_dim: int) → NDArray[float64]

Return the vector that projects the diagonal components onto lambda_0 of reduced_dim.

Parameters:

• reduced_dim – Matrix dimension of the target subspace.

• original_dim – Matrix dimension of the full space.

Returns:

Projection vector \(\vec{v}\) that gives \(\bar{\nu}_0 = \vec{v} \cdot \vec{\nu}\).