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IBM Quantum Platform

commutator

commutator(op_a, op_b)

Computes the commutator of two operators.

The commutator is defined as:

[A,B]=AB−BA[A, B] = AB - BA

Operators which support this method must implement the SupportsCommutators protocol.

Note

Both inputs must be of the same operator type. This will also determine the output type.

>>> from qiskit_bosons.operators import BosonOperator, ann, cre
>>> from qiskit_bosons.operators.library import commutator
>>> b = BosonOperator.from_dict({(ann(0),): 1.0})
>>> b_dag = BosonOperator.from_dict({(cre(0),): 1.0})
>>> commutator(b, b_dag).equiv(BosonOperator.one())
True
>>> n = BosonOperator.from_dict({(cre(0), ann(0)): 1.0})
>>> commutator(n, b_dag).equiv(b_dag)
True
>>> b1_dag = BosonOperator.from_dict({(cre(1),): 1.0})
>>> commutator(b_dag, b1_dag).equiv(BosonOperator.zero())
True

Parameters

  • op_a (T) – the operator AA above.
  • op_b (T) – the operator BB above.

Returns

The commutator [A,B][A, B].

Return type

T

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