2001/08/29 by Todd A. Brun
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1119/1.1475328
published as Am. J. Phys. 70, 719-737 (2002). · 42 pages RevTeX including four figures in encapsulated postscript. Submitted to special issue of American Journal of Physics
arxiv created 2001/08/29 · arxiv updated 2009/12/01
Quantum trajectory theory, developed largely in the quantum optics community to describe open quantum systems subjected to continuous monitoring, has applications in many areas of quantum physics. In this paper I present a simple model, using two-level quantum systems (q-bits), to illustrate the essential physics of quantum trajectories and how different monitoring schemes correspond to different ``unravelings'' of a mixed state master equation. I also comment briefly on the relationship of the theory to the Consistent Histories formalism and to spontaneous collapse models.