lemma
proved
pathWeight_pos
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IndisputableMonolith.Measurement.PathAction on GitHub at line 37.
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34 Complex.exp (- pathAction γ / 2) * Complex.exp (φ * I)
35
36/-- Weight is positive. -/
37lemma pathWeight_pos (γ : RecognitionPath) : 0 < pathWeight γ := by
38 unfold pathWeight
39 exact Real.exp_pos _
40
41/-- Amplitude modulus squared equals weight. -/
42theorem amplitude_mod_sq_eq_weight (γ : RecognitionPath) (φ : ℝ) :
43 ‖pathAmplitude γ φ‖ ^ 2 = pathWeight γ := by
44 unfold pathAmplitude pathWeight
45 have h1 : ‖Complex.exp (-(pathAction γ) / 2)‖ = Real.exp (-(pathAction γ) / 2) := by
46 simpa using Complex.norm_exp_ofReal (-(pathAction γ) / 2)
47 have h2 := Complex.norm_exp_ofReal_mul_I φ
48 rw [norm_mul]
49 simp only [h1, h2, mul_one, sq]
50 rw [← Real.exp_add]
51 ring
52
53end Measurement
54end IndisputableMonolith