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arXiv · 0809.3518

The non-adiabatic pressure in general scalar field systems

Adam J. Christopherson·Karim A. Malik
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Abstract

We discuss the non-adiabatic or entropy perturbation, which controls the evolution of the curvature perturbation in the uniform density gauge, for a scalar field system minimally coupled to gravity with non-canonical action. We highlight the differences between the sound and the phase speed in these systems, and show that the non-adiabatic pressure perturbation vanishes in the single field case, resulting in the conservation of the curvature perturbation on large scales.

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Adam J. Christopherson, Karim A. Malik. 2009-04-17. The non-adiabatic pressure in general scalar field systems. https://doi.org/10.1016/j.physletb.2009.04.003

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