  Motivated by understanding the emergence of thermodynamic restoring forces
and oscillations, we develop a quantum-mechanical model of a bath of spins
coupled to the elasticity of a material. We show our model reproduces the
behavior of a variety of entropic springs while enabling investigation of
non-equilibrium resonator states in the quantum domain. We find our model
emerges naturally in disordered elastic media such as glasses, and is an
additional, expected effect in systems with anomalous specific heat and 1/f
noise at low temperatures due to two-level systems that fluctuate.
