Viscosity in cosmic fluids
| Autor: | Natwariya, Pravin Kumar, Bhatt, Jitesh R, Pandey, Arun Kumar |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Eur. Phys. J. C 80, 767 (2020) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1140/epjc/s10052-020-8341-8 |
| Popis: | The effective theory of large-scale structure formation based on $\Lambda$CDM paradigm predicts finite dissipative effects in the resulting fluid equations. In this work, we study how viscous effect that could arise if one includes self-interaction among the dark-matter particles combines with the effective theory. It is shown that these two possible sources of dissipation can operate together in a cosmic fluid and the interplay between them can play an important role in determining dynamics of the cosmic fluid. In particular, we demonstrate that the viscosity coefficient due to self-interaction is added inversely with the viscosity calculated using effective theory of $\Lambda$CDM model. Thus the larger viscosity has less significant contribution in the effective viscosity. Using the known bounds on $\,\sigma/m$ for self-interacting dark-matter, where $\,\sigma\,$ and $m$ are the cross-section and mass of the dark-matter particles respectively, we discuss role of the effective viscosity in various cosmological scenarios. Comment: 7 pages, Updated to match with the published version |
| Databáze: | arXiv |
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