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Equation 76 · Part 1 · The Clock That Comes Back Wrong by Exactly Its Mass

Symbol Δphi

Δϕ→0\Delta\phi\to0
Δϕ\Delta\phi

What this part means

Δphi 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

Δphi 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

Two degenerate limits of the proper-time form confirm the derivative is doing the right job rather than hiding a division problem. As m→\to0 , Δ\Deltaϕ\phi→\to0 at every fixed Δ\Deltaτ\tau , so the slope — and therefore mopm_{\rm op} — vanishes identically: a massless worldline is exactly the case with no proper time to speak of in the first place, and the formula correctly returns nothing to divide. And if the two branches are held at equal proper time, Δ\Deltaτ\tau=0 , then Δ\Deltaϕ\phi=0 regardless of m ; a single measurement at that one setting is a 0/0 statement about mass, not a small number. Both limits are trivial once stated, and both are exactly why the estimator was built as a slope across a…

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Sources cited in the article section

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