qml.qinfo.transforms.vn_entanglement_entropy¶
- vn_entanglement_entropy(tape, wires0, wires1, base=None, **kwargs)[source]¶
Compute the Von Neumann entanglement entropy from a circuit returning a
state():\[S(\rho_A) = -\text{Tr}[\rho_A \log \rho_A] = -\text{Tr}[\rho_B \log \rho_B] = S(\rho_B)\]where \(S\) is the von Neumann entropy; \(\rho_A = \text{Tr}_B [\rho_{AB}]\) and \(\rho_B = \text{Tr}_A [\rho_{AB}]\) are the reduced density matrices for each partition.
Warning
The
qml.qinfo.vn_entanglement_entropytransform is deprecated and will be removed in v0.40. See thepennylane.vn_entropy()measurement instead.The Von Neumann entanglement entropy is a measure of the degree of quantum entanglement between two subsystems constituting a pure bipartite quantum state. The entropy of entanglement is the Von Neumann entropy of the reduced density matrix for any of the subsystems. If it is non-zero, it indicates the two subsystems are entangled.
- Parameters
tape (QNode or QuantumTape or Callable) – A quantum circuit returning a
state().wires0 (Sequence(int)) – List of wires in the first subsystem.
wires1 (Sequence(int)) – List of wires in the second subsystem.
base (float) – Base for the logarithm. If None, the natural logarithm is used.
- Returns
The transformed circuit as described in
qml.transform. Executing this circuit will provide the entanglement entropy in the form of a tensor.- Return type
qnode (QNode) or quantum function (Callable) or tuple[List[QuantumTape], function]