26/05/2015: "Self-consistent projection operator theory in nonlinear quantum optical systems: A case study on degenerate optical parametric oscillators" by P. Degenfeld-Schonburg, C. Navarrete–Benlloch, and M. J. Hartmann is published in Phys. Rev. A 91, 053850 (2015).
28/04/2015: "Quantum State Engineering with Circuit Electromechanical Three-Body Interactions" by M. Abdi, M. Pernpeintner, R. Gross, H. Huebl, and M. J. Hartmann is published in Phys. Rev. Lett. 114, 173602 (2015).