pygsti.std_matrices

pygsti.std_matrices(dimOrBlockDims)

Get the elements of the matrix unit, or “standard”, basis spanning the density-matrix space given by dimOrBlockDims.

The returned matrices are given in the standard basis of the “embedding” density matrix space, that is, the space which embeds the block-diagonal matrix structure stipulated in dimOrBlockDims. These matrices form an orthonormal basis under the trace inner product, i.e. Tr( dot(Mi,Mj) ) == delta_ij.

Parameters:dimOrBlockDims (int or list of ints) – Structure of the density-matrix space.
Returns:A list of N numpy arrays each of shape (dmDim, dmDim), where dmDim is the matrix-dimension of the overall “embedding” density matrix (the sum of dimOrBlockDims) and N is the dimension of the density-matrix space, equal to sum( block_dim_i^2 ).
Return type:list

Notes

Each element is a matrix containing a single “1” entry amidst a background of zeros, and there are never “1”s in positions outside the block-diagonal structure.