Negative running can prevent eternal inflation

作者：Kinney William H^*; Freese Katherine

来源：Journal of Cosmology and Astroparticle Physics, 2015, 2015(1): 040.

DOI：10.1088/1475-7516/2015/01/040

• inflation
• initial conditions and eternal universe
• physics of the early universe
• gravitational waves and CMBR polarization

Current data from the Planck satellite and the BICEP2 telescope favor, at around the 2 sigma level, negative running of the spectral index of curvature perturbations from inflation. We show that for negative running alpha < 0, the curvature perturbation amplitude has a maximum on scales larger than our current horizon size. A condition for the absence of eternal inflation is that the curvature perturbation amplitude always remain below unity on superhorizon scales. For current bounds on n(S) from Planck, this corresponds to an upper bound of the running alpha < -9 x 10(-5), so that even tiny running of the scalar spectral index is sufficient to prevent eternal inflation from occurring, as long as the running remains negative on scales outside the horizon. In single-field inflation models, negative running is associated with a finite duration of inflation: we show that eternal inflation may not occur even in cases where inflation lasts as long as 10(4) e-folds.

• 出版日期2015-1