---
features:
  - |
    Adds Pauli expectation value snapshot support to the `"density_matrix"`
    simulation method of the :class:`qiskit.providers.aer.QasmSimulator`.
    Add snapshots to circuits using the
    :class:`qiskit.providers.aer.extensions.SnapshotExpectationValue`
    extension.
  - |
    Greatly improves performance of the Pauli expectation value snapshot
    algorithm for the `"statevector"`, `"statevector_gpu`, `"density_matrix"`,
    and `"density_matrix_gpu"` simulation methods of the
    :class:`qiskit.providers.aer.QasmSimulator`.
