CosmoLattice 2.0

Abstract

This paper introduces $\mathcal{C}\mathtt{osmo}\mathcal{L}\mathtt{attice}$ $v2.0$, a major upgrade that substantially broadens the physical scope and computational capabilities of the code. It introduces lattice implementations of scalar fields non-minimally coupled to gravity through $\ddot{I}{•}^{2}R$, as well as axion-like fields coupled to Abelian gauge sectors as $\ddot{I}•F_{\hat{I}¼\hat{I}½}{\tilde{F}}^{\hat{I}¼\hat{I}½}$. It also provides new procedures for generating specialized initial conditions, including scaling networks of cosmic defects ($e.g.$ strings and domain walls), and fields with arbitrary power spectra. The release also incorporates low-storage Runge-Kutta integrators for non-symplectic systems (suitable $e.g.$ for non-minimal scalar kinetic terms as ${\mathcal{G}}_{ab}{\partial }_{\hat{I}}¼\ddot{I}{•}^a{\partial }^{\hat{I}}¼\ddot{I}{•}^b$), scalar-field simulations on reduced $(1+1)$- and $(2+1)$-dimensional lattices, new optimized gravitational-wave evolution, more flexible field and energy-density outputs, and GPU support that can accelerate simulations by a factor $\mathcal{O}(10)$ relative to CPU execution. Extensive documentation on the use of the code is provided on https://www.cosmolattice.com

20 pages + references, 1 figure. v2: minor changes, references added