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Equation 36 · Part 1 · The Bit Comes Back Before the Bearing

Symbol hat g

g^\hat g
g^\hat g

What this part means

hat g is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

hat g is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

For the compass, returned has to mean something else, because g is a continuous parameter and no channel can reproduce an unknown continuous value exactly. The honest promise is metrological: the same agent, using the same R∪\cup CtC_t , applies the best available measurement and estimator g^\hat g , and the achievable mean-squared error is bounded below by the quantum Cramér-Rao bound,

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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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