Published equation contexts

$v^2/c^2 \sim 10^{-8}$

Why this formula appears here

The magnitude is the first surprise. In a driven or flowing lattice, the cone speed along the drift is $c_{\mathrm{eff}}$ + $v_d$ in one direction and $c_{\mathrm{eff}}$ - $v_d$ in the other, so the anisotropy between the along-drift and transverse directions is $\delta$ c/c $\simeq$ $v_d$ / $c_{\mathrm{eff}}$ — first order in the drift velocity, not the crushing second-order $v^2$ / $c^2$ $\sim$ 10^{-8} that made the 1887 experiment so demanding to run and so easy to see nothing in. At a tenth of the cone speed, the anisotropy is ten percent — a signal any competent interferometer would catch on its first pass, the mirror image of the historical null result. Such anisotropies are not a fiction of the model:…

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v^2

Symbol v^2

The square of v: multiply v by itself.

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c^2

Symbol c^2

The square of c: multiply c by itself.

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How to interpret it

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

Research cited beside this formula

[13] Field-Angle Dependence of Sound Velocity in the Weyl Semimetal TaAs ↗

Published contexts (1)

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v^2/c^2 \sim 10^{-8}

Equation 46 · Crossed Fields

Every Crystal Has Its Own Speed of Light

This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text.

The magnitude is the first surprise. In a driven or flowing lattice, the cone speed along the drift is $c_{\mathrm{eff}}$ + $v_d$ in one direction and $c_{\mathrm{eff}}$ - $v_d$ in the other, so the anisotropy between the along-drift and transverse directions is $\delta$ c/c $\simeq$ $v_d$ / $c_{\mathrm{eff}}$ — first order in the drift velocity, not the crushing second-order $v^2$ / $c^2$ $\sim$ 10^{-8} that made the 1887 experiment so demanding to run and so easy to see nothing in. At a tenth of the cone speed, the anisotropy is ten percent — a signal any competent interferometer would catch on its first pass, the mirror image of the historical null result. Such anisotropies are not a fiction of the model:…

Equation guide → · Article →

v2/c2∼10−8v^2/c^2 \sim 10^{-8}v2/c2∼10−8