%0 Generic %1 rampf2020cosmological %A Rampf, Cornelius %A Uhlemann, Cora %A Hahn, Oliver %D 2020 %K tifr %T Cosmological perturbations for two cold fluids in $Łambda$CDM %U http://arxiv.org/abs/2008.09123 %X The cosmic large-scale structure of our Universe is comprised of baryons and cold dark matter (CDM). Yet it is customary to treat these two components as a combined single-matter fluid with vanishing pressure, which is justified only for sufficiently large scales and late times. Here we go beyond the single-fluid approximation and develop the perturbation theory for two gravitationally coupled fluids while still assuming vanishing pressure. We mostly focus on perturbative expansions in powers of $D$ (or $D_+$), the linear structure growth of matter in a $Łambda$CDM Universe with cosmological constant $Łambda$. We derive in particular (1) explicit recursion relations for the two fluid densities, (2) complementary all-order results in the Lagrangian-coordinates approach, as well as (3) the associated component wavefunctions in a semi-classical approach to cosmic large-scale structure. In our companion paper (Hahn et al. 2020) we apply these new theoretical results to generate novel higher-order initial conditions for cosmological hydrodynamical simulations.

@misc{rampf2020cosmological, abstract = {The cosmic large-scale structure of our Universe is comprised of baryons and cold dark matter (CDM). Yet it is customary to treat these two components as a combined single-matter fluid with vanishing pressure, which is justified only for sufficiently large scales and late times. Here we go beyond the single-fluid approximation and develop the perturbation theory for two gravitationally coupled fluids while still assuming vanishing pressure. We mostly focus on perturbative expansions in powers of $D$ (or $D_+$), the linear structure growth of matter in a $\Lambda$CDM Universe with cosmological constant $\Lambda$. We derive in particular (1) explicit recursion relations for the two fluid densities, (2) complementary all-order results in the Lagrangian-coordinates approach, as well as (3) the associated component wavefunctions in a semi-classical approach to cosmic large-scale structure. In our companion paper (Hahn et al. 2020) we apply these new theoretical results to generate novel higher-order initial conditions for cosmological hydrodynamical simulations.}, added-at = {2020-08-24T05:34:40.000+0200}, author = {Rampf, Cornelius and Uhlemann, Cora and Hahn, Oliver}, biburl = {https://www.bibsonomy.org/bibtex/2da2e9313a94818950139605a6e933372/citekhatri}, description = {Cosmological perturbations for two cold fluids in $\Lambda$CDM}, interhash = {771dfdcc6f541966499af75c08b85884}, intrahash = {da2e9313a94818950139605a6e933372}, keywords = {tifr}, note = {cite arxiv:2008.09123Comment: 15 pages + appendices, one figure, MNRAS submitted, comments welcome}, timestamp = {2020-08-24T05:34:40.000+0200}, title = {Cosmological perturbations for two cold fluids in $\Lambda$CDM}, url = {http://arxiv.org/abs/2008.09123}, year = 2020 }