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arXiv · 1009.3326

Scale dependence of $f_{NL}$ in N-flation

Qing-Guo Huang
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Abstract

Adopting the horizon-crossing approximation, we derive the spectral index of $f_{NL}$ in general N-flation model. Axion N-flation model is taken as a typical model for generating a large $f_{NL}$ which characterizes the size of local form bispectrum. We find that its tilt $n_{f_{NL}}$ is negligibly small when all inflatons have the same potential, but a negative detectable $n_{f_{NL}}$ can be achieved in the axion N-flation with different decay constants for different inflatons. The measurement of $n_{f_{NL}}$ can be used to support or falsify the axion N-flation in the near future.

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BibTeXRIS

Qing-Guo Huang. 2010-12-05. Scale dependence of $f_{NL}$ in N-flation. https://doi.org/10.1088/1475-7516%2F2010%2F12%2F017

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