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Paper
IPM / Astronomy / 13670 |
School of Astronomy
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Title: |
In-in and δN calculations of the bispectrum from non-attractor single-field inflation
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Author(s): |
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Status: |
To Appear
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Journal: |
JCAP
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Supported by: |
IPM
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Abstract: |
In non-attractor single-field inflation models producing a scale-invariant power spectrum, the curvature perturbation on super-horizon scales grows as a3. This is so far the only known class of self-consistent single-field models with a Bunch-Davies initial state that can produce a large squeezed-limit bispectrum violating Maldacena's consistency relation. Given the importance of this result, we calculate the bispectrum with three different methods: using quantum field theory calculations in two different gauges, and classical calculations (the δN formalism). All the results agree, giving the local-form bispectrum parameter of flocalNL= 5(1+cs2)/(4cs2). This result is valid for arbitrary values of the speed of sound parameter, cs, for a particular non-attractor model we consider in this paper.
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