← Back to article

Equation 133 · The Bit Comes Back Before the Bearing

What does this equation mean?

tt

Read the formula alongside the article passage below. Each part has a deeper page with its role in the equation, the supporting passage and nearby citations.

This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text. Read the equation part by part below; each part has a contextual explanation and a link to its mathematical background.

Read it piece by piece

tt

Symbol t

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

Understand this part →

How to interpret it

Read this expression with the definitions, units, and assumptions supplied by the article.

What the article says around this equation

A third, more uncomfortable check is what the toy model of the previous section actually implies at the numbers already computed: tLt_L ≈\approx 3.5\,ms\mathrm{ms} , or tLt_L/β\beta ≈\approx 28.2 , for the solar-mass hole above. Taking f1f_1 = 1 as an illustrative, explicitly assumed per-quantum information content, a modest tolerance δ\delta = 0.1\,rad\mathrm{rad} (about six degrees) gives tGt_G/β\beta = 100 , so tGt_G ≈\approx 12.4\,ms\mathrm{ms} and Δ\Delta tLGt_{LG} ≈\approx +8.9\,ms\mathrm{ms} : the compass is the slower debt, as the title claims. But a coarser tolerance, δ\delta = 0.5\,rad\mathrm{rad} (about twenty-nine degrees), gives tGt_G/β\beta = 4 , so tGt_G ≈\approx 0.50\,ms\mathrm{ms} and Δ\Delta tLGt_{LG} ≈\approx…
Read the full surrounding passage
A third, more uncomfortable check is what the toy model of the previous section actually implies at the numbers already computed: tLt_L ≈\approx 3.5\,ms\mathrm{ms} , or tLt_L/β\beta ≈\approx 28.2 , for the solar-mass hole above. Taking f1f_1 = 1 as an illustrative, explicitly assumed per-quantum information content, a modest tolerance δ\delta = 0.1\,rad\mathrm{rad} (about six degrees) gives tGt_G/β\beta = 100 , so tGt_G ≈\approx 12.4\,ms\mathrm{ms} and Δ\Delta tLGt_{LG} ≈\approx +8.9\,ms\mathrm{ms} : the compass is the slower debt, as the title claims. But a coarser tolerance, δ\delta = 0.5\,rad\mathrm{rad} (about twenty-nine degrees), gives tGt_G/β\beta = 4 , so tGt_G ≈\approx 0.50\,ms\mathrm{ms} and Δ\Delta tLGt_{LG} ≈\approx -3.0\,ms\mathrm{ms} : under this same model, on this same hole, the compass now comes back first. The crossover, where 1/(f1f_1δ2\delta^2) = ln⁡\ln S/2π\pi , sits at δ∗\delta^\ast ≈\approx 0.188\,rad\mathrm{rad} , about eleven degrees, for this hole and this choice of f1f_1 . A fourth, trivial floor closes the set of checks: for CtC_t smaller than the input systems themselves, or for t before scrambling has had time to run at all, neither ϵL(t)\epsilon_L(t) nor Var⁡\operatorname{Var}g^\hat g meets any nontrivial bound — nothing has left yet, which is simply causality, not a result.

Read the equation in its article →

Sources cited in the article section

These citations give research context. Read each source to check which claims it supports.

Return to The Bit Comes Back Before the Bearing

Browse the mathematical compendium →