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Equation 69 · Part 1 · A Reference Frame Becomes Classical by Publishing Its Orientation

Symbol F_Q

FQF_Q
FQF_Q

What this part means

FQF_Q 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

FQF_Q 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

under the relevant regularity and unbiasedness conditions. The variance has squared-coordinate units, so FQF_Q has inverse-squared-coordinate units. Paris’s review emphasizes that quantum estimation is an optimization problem over measurements and explains the symmetric-logarithmic-derivative construction used to calculate the bound [ 10 ] .

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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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