Inequivalence of Pure State Ensembles for Open Quantum Systems: The Preferred Ensembles Are Those That Are Physically Realizable
- 20 November 2001
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 87 (24), 240402
- https://doi.org/10.1103/physrevlett.87.240402
Abstract
An open quantum system in steady state can be represented by a weighted ensemble of pure states in infinitely many ways. A physically realizable (PR) ensemble is one for which some continuous measurement of the environment will collapse the system into a pure state , stochastically evolving such that the proportion of time for which equals . Some, but not all, ensembles are PR. This constitutes the preferred ensemble fact. We present the necessary and sufficient conditions for a given ensemble to be PR, and illustrate the method by showing that the coherent state ensemble is not PR for an atom laser.
Keywords
This publication has 9 references indexed in Scilit:
- Robustness and Diffusion of Pointer StatesPhysical Review Letters, 2000
- Postselected versus nonpostselected quantum teleportation using parametric down-conversionPhysical Review A, 2000
- Quantum NoiseSpringer Series in Synergetics, 2000
- Maximally robust unravelings of quantum master equationsPhysics Letters A, 1998
- Defining the (atom) laserPhysical Review A, 1997
- Optical coherence: A convenient fictionPhysical Review A, 1997
- Quantum OpticsPublished by Springer Science and Business Media LLC ,1994
- A complete classification of quantum ensembles having a given density matrixPhysics Letters A, 1993
- Conceptual Foundations of Quantum MechanicsAmerican Journal of Physics, 1978