# Open quantum systems are harder to track than open classical systems

@article{Warszawski2019OpenQS,
title={Open quantum systems are harder to track than open classical systems},
author={Prahlad Warszawski and Howard M. Wiseman},
journal={Quantum},
year={2019}
}
• Published 27 May 2019
• Computer Science
• Quantum
For a Markovian (in the strongest sense) open quantum system it is possible, by continuously monitoring the environment, to perfectly track the system; that is, to know the stochastically evolving pure state of the system without altering the master equation. In general, even for a system with a finite Hilbert space dimension D, the pure state trajectory will explore an infinite number of points in Hilbert space, meaning that the dimension K of the classical memory required for the tracking is…
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