Interacting quantum trajectories for particles with spin 1/2

In recent decades, the de Broglie-Bohm or 'pilot wave' interpretation of quantum mechanics-especially its concept of the 'quantum trajectory'-has inspired a plethora of computational methods in molecular and chemical physics. One particularly promising subclass of such methods are the 'interacting quantum trajectory' (IQT) methods, for which an ensemble of trajectories is propagated independently of-and without any recourse to-an underlying wavefunction. In this work, an IQT version of the Pauli equation is developed-enabling spin to be incorporated into IQT theories for the first time, to the authors' knowledge. The new trajectory-based dynamical equations are then used to solve two iconic quantum problems involving spin: the 'quantum spin flipper', and the Stern-Gerlach experiment.