proper normalization

QuantumSavory · Nov 16, 2024 · 84383f2 · 84383f2
1 parent 854e5c5
commit 84383f2
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/src/nonclifford.jl b/src/nonclifford.jl
@@ -237,8 +237,10 @@ function _proj(sm::GeneralizedStabilizer, p::PauliOperator)
     # where (S′, D′) is derived from (S, D) through the traditional stabilizer update,
     # and χ′ is the updated density matrix after measurement. Note: Λ(χ′) ≤ Λ(χ).
     n = nqubits(sm)
+    # The trace Tr[sm′] = Tr[χᵢⱼ′] serves as the normalization required for sm′.
+    χ′′ = expect(p, sm)/LinearAlgebra.tr(expect(p, sm))
     state, res = projectrand!(sm.stab, p)
-    sm = GeneralizedStabilizer(state, DefaultDict(0.0im, (falses(n),falses(n))=>expect(p, sm)))
+    sm = GeneralizedStabilizer(state, DefaultDict(0.0im, (falses(n),falses(n))=>χ′′))
     return sm, res
 end