Numerical Investigation of Cosmological Singularities

We describe a numerical approach to address the BKL conjecture that the generic cosmological singularity is locally Mixmaster-like. We consider application of a symplectic PDE solver to three models of increasing complexity–spatially homogeneous (vacuum) Mixmaster cosmologies where we compare the symplectic ODE solver to a Runge-Kutta one, the (plane symmetric, vacuum) Gowdy universe on $T^3\times R$ whose dynamical degrees of freedom satisfy nonlinearly coupled PDE’s in one spatial dimension and time, and U(1) symmetric, vacuum cosmologies on $T^3\times R$ which are the simplest spatially inhomogeneous universes in which local Mixmaster dynamics is allowed.