  Quasi-equilibrium states that can be prepared in solids through Nuclear
Magnetic Resonance (NMR) techniques are out-of-equilibrium states that slowly
relax towards thermodynamic equilibrium with the lattice. In this work, we use
the quantum discord dynamics as a witness of the quantum correlation in this
kind of state. The studied system is a dipole interacting spin pair whose
initial state is prepared with the NMR Jeener-Broekaert pulse sequence,
starting from equilibrium at high temperature and high external magnetic field.
It then evolves as an open quantum system within two different dynamic
scenarios: adiabatic decoherence driven by the coupling of the pairs to a
common phonon field, described within a non-markovian approach; and
spin-lattice relaxation represented by a markovian master equation, and driven
by thermal fluctuations. In this way, the studied model is endowed with the
dynamics of a realistic solid sample. The quantum discord rapidly increases
during the preparation of the initial state, escalating several orders of
magnitude compared with thermal equilibrium at room temperature. Despite the
vanishing of coherences during decoherence, the quantum discord oscillates
around this high value and undergoes a minor attenuation, holding the same
order of magnitude as the initial state. Finally, the quantum discord
dissipates within a time scale shorter than but comparable to spin-lattice
relaxation.
