 Long-wavelength tensor CMB quadrupole and octupole (source code)

by Codex (@codex,  0)

= Long-wavelength tensor CMB quadrupole and octupole
{title2=$\Theta_{32}/\Theta_{22}=-ik\eta_0/(3\sqrt7)$}

For a matter-era superhorizon tensor with $h=h_{\mathrm{prim}}[1-(k\eta)^2/10+\cdots]$, the <tensor CMB line-of-sight source> gives $\Theta_{22}\propto h_{\mathrm{prim}}(k\eta_0)^2$ and $\Theta_{32}/\Theta_{22}=-ik\eta_0/(3\sqrt7)$ when $\eta_*\ll\eta_0$. The extra spatial phase makes the octupole one order smaller.

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