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Equation 98 · Part 4 · The Atlas That Refuses to Close

Symbol i

⟨f∣σz∣ψ⟩=12(1+i)\langle f|\sigma_z|\psi\rangle = \tfrac12(1+i)
ii

What this part means

i is one of the signed contributions combined to compute the quantity on the left.

Its job in the formula

i is one of the signed contributions combined to compute the quantity on the left.

The passage around this formula

​ 1 ​ ( ∣ ↑ ⟩ + i ∣ ↓ ⟩) . Then ⟨\langle f|ψ\psi⟩\rangle = 12(1−i)\tfrac12(1-i) and ⟨\langle f|σz\sigma_z|ψ\psi⟩\rangle = 12(1+i)\tfrac12(1+i) , so the weak value of σz\sigma_z is

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Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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Sources cited in the article section

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