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      Kinetic Field Theory: Effects of momentum correlations on the cosmic density-fluctuation power spectrum

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          Abstract

          In earlier work, we have developed a Kinetic Field Theory (KFT) for cosmological structure formation and showed that the non-linear density-fluctuation power spectrum known from numerical simulations can be reproduced quite well even if particle interactions are taken into account to first order only. Besides approximating gravitational interactions, we had to truncate the initial correlation hierarchy of particle momenta at the second order. Here, we substantially simplify KFT. We show that its central object, the free generating functional, can be factorized, taking the full hierarchy of momentum correlations into account. The factors appearing in the generating functional have a universal form and can thus be tabulated for fast access in perturbation schemes. Our results show that the complete hierarchy of initial momentum correlations is responsible for a characteristic deformation in the density-fluctuation power spectrum, caused by mode transport independent of the particle interaction. At the present epoch and on scales near \(1\,h^{-1}\mathrm{Mpc}\), the initial momentum correlations can almost double the linearly evolved power. We further develop perturbation theory based on the factorization of the generating functional and propose a diagrammatic scheme for the perturbation terms.

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          Author and article information

          Journal
          2016-11-29
          Article
          1611.09503
          c622ade2-f872-4889-a3f6-d36c7e473888

          http://arxiv.org/licenses/nonexclusive-distrib/1.0/

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          Custom metadata
          29 pages, 9 figures
          astro-ph.CO

          Cosmology & Extragalactic astrophysics
          Cosmology & Extragalactic astrophysics

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