Complete parameterization, and invariance, of diffusive quantum trajectories for Markovian open systems

Citation
Hm. Wiseman et L. Diosi, Complete parameterization, and invariance, of diffusive quantum trajectories for Markovian open systems, CHEM PHYS, 268(1-3), 2001, pp. 91-104
Citations number
35
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
CHEMICAL PHYSICS
ISSN journal
03010104 → ACNP
Volume
268
Issue
1-3
Year of publication
2001
Pages
91 - 104
Database
ISI
SICI code
0301-0104(20010615)268:1-3<91:CPAIOD>2.0.ZU;2-C
Abstract
The state matrix rho for an open quantum system with Markovian evolution ob eys a master equation. The master equation evolution can be unraveled into stochastic nonlinear trajectories for a pure state P, such that on average P reproduces rho. Here we give for the first time a complete parameterizati on of all diffusive unravelings (in which P evolves continuously but non-di fferentiably in time). We give an explicit measurement theory interpretatio n for these quantum trajectories, in terms of monitoring the system's envir onment. We also introduce new classes of diffusive unravelings that are inv ariant under the linear operator transformations under which the master equ ation is invariant. We illustrate these invariant unravelings by numerical simulations. Finally, we discuss generalized gauge transformations as a met hod of connecting apparently disparate descriptions of the same trajectorie s by stochastic Schrodinger equations, and their invariance properties. (C) 2001 Elsevier Science B.V. All rights reserved.