TY - JOUR

T1 - Notes on natural inflation

AU - Yonekura, Kazuya

PY - 2014/10/1

Y1 - 2014/10/1

N2 - In the so-called natural inflation, an axion-like inflaton is assumed to have a cosine-type periodic potential. This is not the case in a very simple model in which the axion-like inflaton is coupled to an SU(N) (or other) pure Yang-Mills, at least in the large N limit as pointed out by Witten. It has a multi-valued potential, which is effectively quadratic, i.e., there is only a mass term in the large N limit. Thanks to this property, chaotic inflation can be realized more naturally with the decay constant of the axion-like inflaton less than the Planck scale. We demonstrate these points explicitly by using softly broken =1 Super-Yang-Mills which allows us to treat finite N. This analysis also suggests that moderately large gauge groups such as E8 are good enough with a Planck scale decay constant.

AB - In the so-called natural inflation, an axion-like inflaton is assumed to have a cosine-type periodic potential. This is not the case in a very simple model in which the axion-like inflaton is coupled to an SU(N) (or other) pure Yang-Mills, at least in the large N limit as pointed out by Witten. It has a multi-valued potential, which is effectively quadratic, i.e., there is only a mass term in the large N limit. Thanks to this property, chaotic inflation can be realized more naturally with the decay constant of the axion-like inflaton less than the Planck scale. We demonstrate these points explicitly by using softly broken =1 Super-Yang-Mills which allows us to treat finite N. This analysis also suggests that moderately large gauge groups such as E8 are good enough with a Planck scale decay constant.

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U2 - 10.1088/1475-7516/2014/10/054

DO - 10.1088/1475-7516/2014/10/054

M3 - Article

AN - SCOPUS:84908620585

SN - 1475-7516

VL - 2014

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

IS - 10

M1 - 054

ER -