  The temperature dependence of the chiral condensate in isospin-symmetric
nuclear matter at varying baryon density is investigated using thermal
in-medium chiral effective field theory. This framework provides a realistic
approach to the thermodynamics of the correlated nuclear many-body system and
permits calculating systematically the pion-mass dependence of the free energy
per particle. One- and two-pion exchange processes, $\Delta(1232)$-isobar
excitations, Pauli blocking corrections and three-body correlations are treated
up to and including three loops in the expansion of the free energy density. It
is found that nuclear matter remains in the Nambu-Goldstone phase with
spontaneously broken chiral symmetry in the temperature range $T\lesssim
100\,$MeV and at baryon densities at least up to about twice the density of
normal nuclear matter, $2\rho_0 \simeq 0.3\, $fm$^{-3}$. Effects of the nuclear
liquid-gas phase transition on the chiral condensate at low temperatures are
also discussed.

Nuclear Theory