Inertial Trajectories in de Broglie-Bohm Theory: an unexpected problem

A salient feature of de Broglie-Bohm quantum theory is that particles have de-terminate positions at all times and in all physical contexts. Hence, the trajec-tory of a particle is a well-defined concept. One then may expect that the closely related notion of inertial trajectory is also unproblematically defined. I show that this expectation is not met. I provide a framework that deploys six different ways in which de Broglie-Bohm theory can be interpreted, and I state that only in the canonical interpretation the concept of inertial trajectory is the customary one. However, in this interpretation the description of the dynamical interac-tion between the pilot-wave and the particles, which is crucial to distinguish inertial from non-inertial trajectories, is affected by serious difficulties, so other readings of the theory intend to avoid them. I show that in the alternative in-terpretations the concept at issue gets either drastically altered, or plainly un-defined. I also spell out further conceptual difficulties that are associated to the redefinitions of inertial trajectories, or to the absence of the concept