qml.qinfo

Overview

This module provides a collection of methods to return quantum information quantities from QNode returning state().

Transforms

QNode transforms for the quantum information quantities.

Functions

fidelity(qnode0, qnode1, wires0, wires1)

Compute the fidelity for two QNode returning a state() (a state can be a state vector or a density matrix, depending on the device) acting on quantum systems with the same size.

mutual_info(tape, wires0, wires1[, base])

Compute the mutual information from a QuantumTape returning a state():

purity(tape, wires, **kwargs)

Compute the purity of a QuantumTape returning state().

qnode_execution_wrapper(self, qnode, targs, …)

Here, we overwrite the QNode execution wrapper in order to take into account that classical processing may be present inside the QNode.

reduced_dm(tape, wires, **kwargs)

Compute the reduced density matrix from a QNode returning state().

relative_entropy(qnode0, qnode1, wires0, wires1)

Compute the relative entropy for two QNode returning a state() (a state can be a state vector or a density matrix, depending on the device) acting on quantum systems with the same size.

trace_distance(qnode0, qnode1, wires0, wires1)

Compute the trace distance for two QNode returning a state() (a state can be a state vector or a density matrix, depending on the device) acting on quantum systems with the same size.

vn_entanglement_entropy(tape, wires0, wires1)

Compute the Von Neumann entanglement entropy from a circuit returning a state():

vn_entropy(tape, wires[, base])

Compute the Von Neumann entropy from a QuantumTape returning a state().