How Many Bits Does It Take to Track an Open Quantum System?

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Title How Many Bits Does It Take to Track an Open Quantum System?
Author Karasik, Raisa; Wiseman, Howard Mark
Journal Name Physical Review Letters
Year Published 2011
Place of publication United States
Publisher American Physical Society
Abstract A D-dimensional Markovian open quantum system will undergo quantum jumps between pure states, if we can monitor the bath to which it is coupled with sufficient precision. In general, these jumps, plus the between-jump evolution, create a trajectory which passes through infinitely many different pure states. Here we show that, for any ergodic master equation, one can expect to find an adaptive monitoring scheme on the bath that can confine the system state to jumping between only K states, for some K≥(D-1)2+1. For D=2 we explicitly construct a two-state ensemble for any ergodic master equation, showing that one bit is always sufficient to track a qubit.
Peer Reviewed Yes
Published Yes
Alternative URI http://dx.doi.org/10.1103/PhysRevLett.106.020406
Copyright Statement Copyright 2011 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 106
Issue Number 2
Page from 020406-1
Page to 020406-4
ISSN 0031-9007
Date Accessioned 2011-09-21
Language en_US
Research Centre Centre for Quantum Dynamics
Faculty Faculty of Science, Environment, Engineering and Technology
Subject Quantum Information, Computation and Communication; Quantum Optics; Quantum Physics
URI http://hdl.handle.net/10072/42800
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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