Stolze, JoachimMüller, LotharLeschke, HajoNagel, Peter2008-06-032008-06-031990Müller, Lothar; Stolze, Joachim; Leschke, Hajo, Nagel, Peter: Classical and quantum phase-space behavior of a spin-boson system. In: Physical Review A Nr. 2, Jg. 44(1991), S. 1022-1033, doi: 10.1103/PhysRevA.44.1022 .http://hdl.handle.net/2003/2542610.17877/DE290R-3358We study the phase-space behavior of the standard two-level system (spin 1/2) coupled to a harmonic oscillator (without the rotating-wave approximation), the classical counterpart of which is known to display deterministic chaos. We study the quantum-mechanical phase-space behavior by means of harmonic-oscillator coherent states (Husimi representation). Stationary quantum Poincaré sections may be defined; they show many parallels to their classical counterparts. We also study the time development of initially coherent states and observe a tendency towards a decay into many small wave packets in phase space for parameters in the chaotic regime.enThe American Physical Society51010.1103/PhysRevA.44.1022article (journal)