Equation 49 · The Bit Comes Back Before the Bearing
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Symbol g
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The reason those two questions come apart is not decoder cleverness. It is that g is what Bartlett, Rudolph, and Spekkens call unspeakable information: a fact that cannot be conveyed by any classical message alone, because there is no such thing as “the direction north” without a physical system that already points north to compare against [ 9 ] . A qubit’s logical content — which of two orthogonal states it is closer to — can be copied onto a classical bit string and handed over on a slip of paper; a heading cannot, not even in principle, because a slip of paper has no intrinsic orientation relative to anything until a further physical frame is supplied to read it against.
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