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Equation 7 · Part 6 · The Corner of the Equivalence Principle No Experiment Has Touched

Symbol hateta_ent

η^=ηcl+η^diag+η^coh+η^sup+η^ent\hat\eta = \eta_{cl} + \hat\eta_{diag} + \hat\eta_{coh} + \hat\eta_{sup} + \hat\eta_{ent}
η^ent\hat\eta_{ent}

What this part means

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

Its job in the formula

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

The passage around this formula

…any classical trajectory would need, the component that a spatial superposition test — an atom interferometer’s two arms treated as a single quantum object rather than two separate classical paths — is built to see. And η^ent\hat\eta_{ent} is the one component with no single-system analogue at all: it is defined only on a joint state of two systems, and it is nonzero precisely when the expectation value of the joint operator on an entangled state fails to equal the sum of what each system would show alone,…

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Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

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Sources cited in the surrounding passage

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