Sergio Albeverio, Yuri Kondratiev, Yuri Kozitsky, Michael, Roeckner Uniqueness for Gibbs States of Quantum Lattices in Small Mass Regime (61K, LaTeX 2e) ABSTRACT. The model of interacting quantum particles performing anharmonic one--dimensional oscillations around their unstable equilibrium positions, which form the $d$-dimensional simple cubic lattice, is considered. For this model, it is proved that for every fixed value of temperature, there exists a positive quantity (temperature depending) such that for all values of the physical mass of the particle less than this quantity, the set of tempered Gibbs states of the model consists of exactly one element.