We showed several years ago that the density operator of Markovian open systems can be diagonalized continuously in time. The resulting pure state jump processes correspond to quantum trajectories proposed in recent quantum optics calculations or, at fundamental level, to exact consistent histories. The quantum state of an open quantum system — actually a subsystem of a closed one — cannot be d...

This case study involves a patient who presented at a chiropractic clinic with an acute torticollis. Although preceding trauma was sincerely denied by the patient, a thorough case history with appropriate radiological investigation revealed a Jefferson fracture with an associated rupture of the osseous attachment of the transverse ligament.

In the consistent histories formalism one specifies a family of histories as an exhaustive set of pairwise exclusive descriptions of the dynamics of a quantum system. We define branching families of histories, which strike a middle ground between the two available mathematically precise definitions of families of histories, viz., product families and Isham’s history projector operator formalism...