qat.quops.QuantumChannelChi

class qat.quops.QuantumChannelChi(matrix, matrix_basis, name='')

A quantum channel in its Chi matrix representation.

\[\mathcal{E}(\boldsymbol{\rho})=\sum_{ij}\chi_{ij}^{(A)}\boldsymbol{A}_{i}\boldsymbol{\rho}\boldsymbol{A}_{j}^{\dagger}\]

Parameters:

• matrix (np.array) – the Chi matrix \(\chi_{ij}^{(A)}\)

• matrix_basis (list<np.array>) – the matrix basis \(\boldsymbol{A}_{i}\)

• name (str) – the name of the channel

matrix

the Chi matrix \(\chi_{ij}^{(A)}\)

Type:

np.array

matrix_basis

the matrix basis \(\boldsymbol{A}_{i}\)

Type:

list<np.array>

name

the name of the channel

Type:

str

arity

the arity of the gate

Type:

int

apply_to(rho)

Apply the channel to a density matrix

Parameters:

rho (np.array) – a density matrix

Returns:

the transformed density matrix

Return type:

np.array

to_kraus()

Convert to Kraus representation

Returns:

QuantumChannelKraus