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On the Entropy and the Density Matrix of Cosmological Perturbations

I. L. Egusquiza·A. Feinstein·M. A. Perez Sebastian·M. A. Valle Basagoiti
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Abstract

We look at the transition to the semiclassical behaviour and the decoherence process for the inhomogeneous perturbations in the inflationary universe. Two different decoherence mechanisms appear: one dynamical, accompanied with a negligible, if at all, entropy gain, and the other, effectively irreversible dephasing, due to a rapid variation in time of the off-diagonal density matrix elements in the post-inflationary epoch. We thus settle the discrepancies in the entropy content of perturbations evaluated by different authors.

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I. L. Egusquiza, A. Feinstein, M. A. Perez Sebastian, M. A. Valle Basagoiti. 1997-09-24. On the Entropy and the Density Matrix of Cosmological Perturbations. https://doi.org/10.1088/0264-9381%2F15%2F7%2F010

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