On cross-correlations between curvature and isocurvature perturbations during inflation

Journal Article · Mon Feb 01 04:00:00 EST 2010 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2010/02/019· OSTI ID:22272985

Gao, Xian ^[1]

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1. Key Laboratory of Frontiers in Theoretical Physics, Kavli Institute for Theoretical Physics China, Chinese Academy of Sciences, Beijing 100190 (China)

We investigate the effects of couplings between curvature and isocurvature perturbations before and around horizon-crossings during cosmological inflation. We consider a generalized two-field inflation model, in which the non-canonical kinetic term allows us arbitrary sound speeds of curvature and isocurvature perturbations. By using the field-theoretical perturbative analysis, we calculate the cross-spectrum between curvature and isocurvature perturbations and the corrections to curvature and isocurvature power spectra due to the presence of couplings between them. Our analysis confirms previous results that the cross-correlations are generated and amplified when perturbations cross the horizons. Moreover, we find the cross-correlation, which was previously shown to be first-order in slow-roll parameter, can be enhanced when the sound speed of curvature perturbation is much larger than that of the isocurvature perturbation. This is because in this case the isocurvature perturbation exits its horizon much earlier than the curvature perturbation and acts as a nearly constant source on the curvature perturbation.

• OSTI ID: 22272985
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 02 Vol. 2010; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CORRECTIONS
CORRELATIONS
COSMOLOGY
DISTURBANCES
INFLATIONARY UNIVERSE
SOUND WAVES
VELOCITY