A density matrix representation of a mixed quantum state
Return the density matrix as a square array
Returns: The state probabilities
Return the trace of this density operator
A quantum channel
Return the Hermitian conjugate of this quantum operation.
For unitary Gates (and Circuits composed of the same) the Hermitian conjugate returns the inverse Gate (or Circuit)
ValueError – If this operation does not support Hermitian conjugate
Convert this quantum operation to a channel (if possible).
ValueError – If this operation cannot be converted to a Channel
Convert this quantum operation to a gate (if possible).
ValueError – If this operation cannot be converted to a Gate
Return the chi (or process) matrix representation of this superoperator
Return the Choi matrix representation of this super operator
Return a Channel from a Choi matrix
Return the name of this Operation
Return the ‘sharp’ transpose of the superoperator.
The transpose \(S^\#\) switches the two covariant (bra) indices of the superoperator. (Which in our representation are the 2nd and 3rd super-indices)
If \(S^\#\) is Hermitian, then \(S\) is a Hermitian-map (i.e. transforms Hermitian operators to Hermitian operators)
Flattening the \(S^\#\) superoperator to a matrix gives the Choi matrix representation. (See channel.choi())
Return the tensor representation of the channel’s superoperator
Return the trace of this super operator
A Kraus representation of a quantum channel
Not possible in general. (But see UnitaryMixture)
Raises: TypeError
List of qubits acted upon by this Kraus operation
The list of qubits is ordered if the qubits labels can be sorted, else the the order is indeterminate.
TypeError – If qubits cannot be sorted into unique order.
Returns
A Kraus channel which is a convex mixture of unitary dynamics.
This Channel is unital, but not all unital channels are unitary mixtures.
Return one of the composite Kraus operators at random with the appropriate weights
Returns the completely mixed density matrix
Returns: A randomly sampled Density
qubits – A list or number of qubits.
rank – Rank of density matrix. (Defaults to full rank)
ensemble – Either ‘Hilbert–Schmidt’ (default) or ‘Burr’
“Induced.info in the space of mixed quantum states” Karol Zyczkowski, Hans-Juergen Sommers, J. Phys. A34, 7111-7125 (2001) arXiv:quant-ph/0012101
“Random Bures mixed states and the distribution of their purity”, Osipov, Sommers, and Zyczkowski, J. Phys. A: Math. Theor. 43, 055302 (2010). arXiv:0909.5094
Join two channels acting on different qubits into a single channel acting on all qubits
A Kraus representation of a phase-damping quantum channel
prob – The one-step damping probability.
q0 – The qubit on which to act.
A Kraus representation of an amplitude-damping (spontaneous emission) channel on one qubit
prob – The one-step damping probability.
q0 – The qubit on which to act.
A Kraus representation of a depolarizing channel on 1-qubit.
prob – The one-step depolarizing probability.
q0 – The qubit on which to act.
Returns: A randomly sampled Channel drawn from the BCSZ ensemble with the specified Kraus rank.
qubits – A list, or number, of qubits.
rank – Kraus rank of channel. (Defaults to full rank)
“Random quantum operations”, Bruzda, Cappellini, Sommers, and Zyczkowski, Physics Letters A 373, 320 (2009). arXiv:0804.2361