Equation 100 · Part 2 · The Bit Comes Back Before the Bearing

Symbol f_1

1/(N f_1)

f_1

What this part means

the per-probe fisher information.

Its job in the formula

$f_1$ is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Full expressionSymbol f_1Article meaning

Where the article explains it

This is the standard-quantum-limit regime of parameter estimation: for N independent, identically prepared probes each with per-probe Fisher information $f_1$ , the achievable variance scales as 1/(N $f_1$ ) , in contrast to the quadratically better Heisenberg scaling available only when probes are used coherently together [ 13 ] .

The passage around this formula

…like an independent sample rather than like a decoded codeword. This is the standard-quantum-limit regime of parameter estimation: for N independent, identically prepared probes each with per-probe Fisher information $f_1$ , the achievable variance scales as 1/(N $f_1$ ) , in contrast to the quadratically better Heisenberg scaling available only when probes are used coherently together [ 13 ] . Modeling the collected radiation up to time t as contributing $N_\gamma(t)$ $\sim$ t/ $\beta$ roughly independent quanta gives, as…

Read this part in the article →

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.

Open the illustrated subscripts: which member of a family? guide →

See this notation across published equations →

Sources cited in the surrounding passage

These citations provide research context; check each source for the exact claim it supports.