Analytical checks for a GPU-based relativistic viscous hydrodynamic code in 3+1 dimensions

Heavy-ion collisions produce a nearly perfect fluid with the smallest viscosities measured in any system known to humanity. However, the system may begin very far from equilibrium, necessitating the use of relativistic viscous hydrodynamics to handle such initial conditions. Additionally, high-energy heavy-ion collisions are essentially boost-invariant, meaning that only 2+1 dimensions (D) are typically required. At low energies, however, fully 3+1D simulations with conserved charges are necessary. In this work, we extend the Smoothed Particle Hydrodynamic relativistic viscous hydrodynamic code with conserved charges, CCAKE, originally developed in 2+1D, to 3+1D. We compare this CCAKE 2.0 code to known analytical solutions in 1+1D. Due to significantly longer run times in 3+1D, CCAKE has been upgraded with novel improvements in performance portability and scalability, now running with Kokkos and Cabana, allowing it to efficiently run on both CPU and GPU architectures. To benchmark the functionality of CCAKE 2.0, we developed new semi-analytical solutions for the evolution of both temperature and chemical potentials in viscous Gubser flow with conserved charges, and demonstrate that CCAKE 2.0 accurately reproduces these solutions. Speed gains and future steps will be discussed.