Redfield Dynamics of a Quantum Spherical Spin
The temporal evolution of a quantum spherical spin in contact with a thermal bath is studied by solving the exact Redfield equation, in order to evaluate the effect of the frequently used Lindblad approximation. This simple model can be used as a starting point for the study of more complex open quantum systems. Significant discrepancies are observed for short times. In the equilibrium state both models give identical results, as expected.