Loop-Induced Stochastic Bias at Small Wavevectors

Understand

Primordial non-Gaussianities enhanced at small wavevectors can induce a power spectrum of the galaxy overdensity that differs greatly from that of the matter overdensity at large length scales.

• In previous work, it was shown that "squeezed" three-point and "collapsed" four-point functions of the curvature perturbation $\zeta$ can generate these non-Gaussianities and give rise to so-called scale-dependent and stochastic bias in the galaxy overdensity power spectrum.
• We explore a third way to generate non-Gaussianities enhanced at small wavevectors: the infrared behavior of quantum loop contributions to the four-point correlations of $\zeta$.
• We show that these loop effects lead to stochastic bias, which can be observable in the context of quasi-single field inflation.