  Measurements of neutron star mass and radius or tidal deformability deliver
unique insight into the equation of state (EOS) of cold dense matter. EOS
inference is very often done using generalized parametric or non-parametric
models which deliver no information on composition. In this paper we consider a
microscopic nuclear EOS model based on a field theoretical approach. We show
that current measurements from NICER and gravitational wave observations
constrain primarily the symmetric nuclear matter EOS. We then explore what
could be delivered by measurements of mass and radius at the level anticipated
for future large-area X-ray timing telescopes. These should be able to place
very strong limits on the symmetric nuclear matter EOS, in addition to
constraining the nuclear symmetry energy that determines the proton fraction
inside the neutron star.
