Non-Markovian stochastic Schrodinger equations: Generalization to real-valued noise using quantum measurement theory.

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Title Non-Markovian stochastic Schrodinger equations: Generalization to real-valued noise using quantum measurement theory.
Author Gambetta, Jay; Wiseman, Howard Mark
Journal Name Physical Review A: Atomic, Molecular and Optical Physics
Year Published 2002
Place of publication USA
Publisher American Physical Society
Abstract Do stochastic Schrödinger equations, also known as unravelings, have a physical interpretation? In the Markovian limit, where the system on average obeys a master equation, the answer is yes. Markovian stochastic Schrödinger equations generate quantum trajectories for the system state conditioned on continuously monitoring the bath. For a given master equation, there are many different unravelings, corresponding to different sorts of measurement on the bath. In this paper we address the non-Markovian case, and in particular the sort of stochastic Schrödinger equation introduced by Strunz, Diósi, and Gisin [Phys. Rev. Lett. 82, 1801 (1999)]. Using a quantum-measurement theory approach, we rederive their unraveling that involves complex-valued Gaussian noise. We also derive an unraveling involving real-valued Gaussian noise. We show that in the Markovian limit, these two unravelings correspond to heterodyne and homodyne detection, respectively. Although we use quantum-measurement theory to define these unravelings, we conclude that the stochastic evolution of the system state is not a true quantum trajectory, as the identity of the state through time is a fiction.
Peer Reviewed Yes
Published Yes
Publisher URI http://prola.aps.org/
Alternative URI http://dx.doi.org/10.1103/PhysRevA.66.012108
Copyright Statement Copyright 2002 American Physical Society. This is the author-manuscript version of this paper. Reproduced in accordance with the copyright policy of the publisher. Please refer to the journal's website for access to the definitive, published version.
Volume 66
Page from 012108.1
Page to 012108.17
ISSN 1050-2947
Date Accessioned 2003-04-11
Date Available 2009-10-12T23:13:03Z
Language en_AU
Research Centre Centre for Quantum Dynamics
Faculty Faculty of Science
Subject PRE2009-Theoretical Physics
URI http://hdl.handle.net/10072/6989
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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