Wolodymyr Skrypnik (Institute of Mathematics of NAS of Ukraine, Kyiv, Ukraine)

Order parameters in quantum quasi-integrable lattice systems of oscillators and spins

Quantum systems of interacting spins and oscillators, whose coordinates are indexed by sites of the hyper-cubic lattice Zd, with Gibbsian ground states are found. Conditions which lead to existence of several order parameters are formulated.