Relativistic Navier-Stokes: recent developments

The Navier-Stokes equations are ubiquitous in the physical description of our universe, but their relativistic counterpart, as originally formulated many decades ago, suffer severe issues. In recent years, a well-behaved version of relativistic Navier-Stokes has been proposed, satisfying good properties of well-posedness and causality.

Alternative formulations, like the widely used Muller-Israel-Stewart (MIS) theories that successfully describe the quark-gluon plasma, are known to present limitations. Moreover, weak processes in neutron star mergers are believed to give rise to an effective viscosity, for which MIS descriptions find similar limitations.

We present recent developments in numerical evolutions of the relativistic Navier-Stokes equations, pointing to the description of these systems, as a promising approach for which these limitations are absent.