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arXiv · gr-qc/9512049

Quantum Origin of Noise and Fluctuations in Cosmology

B. L. Hu·Juan Pablo Paz·Yuhong Zhang
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Abstract

We address two basic issues in the theory of galaxy formation from fluctuations of quantum fields: 1) the nature and origin of noise and fluctuations and 2) the conditions for using a classical stochastic equation for their description. On the first issue, we derive the influence functional for a $λϕ^4 $ field in a zero-temperature bath in de Sitter universe and obtain the correlator for the colored noises of vacuum fluctuations. This exemplifies a new mechanism we propose for colored noise generation which can act as seeds for galaxy formation with non-Gaussian distributions. For the second issue, we present a (functional) master equation for the inflaton field in de Sitter universe. By examining the form of the noise kernel we study the decoherence of the long-wavelength sector and the conditions for it to behave classically.

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B. L. Hu, Juan Pablo Paz, Yuhong Zhang. 1995-12-29. Quantum Origin of Noise and Fluctuations in Cosmology. https://arxiv.org/abs/gr-qc/9512049

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