ppvm_tableau::expectation

expectation¶

ppvm_tableau::expectation

Pauli-string expectation values and pattern traces. Pauli-string expectation values for `GeneralizedTableau`.

Two entry points:

• [`GeneralizedTableau::expectation`] — single-Pauli `⟨ψ|P|ψ⟩` for a `PauliWord`. Conjugates `P` through the tableau and overlaps the resulting Pauli with the sparse coefficient vector using the same formulas as the measurement code.
• [`GeneralizedTableau::trace`] — `Σ_{P matches pattern} ⟨ψ|P|ψ⟩` for a `PauliPattern`. Enumerates the matching Paulis and sums their expectations.

Decision 9 in the multi-backend plan calls these out as the natural primitive for the tableau backend; semantics intentionally diverge from the PauliSum trace.