Continuous Position Measurements and the Quantum Zeno Effect

Gagen, M. J., Wiseman, H. M. and Milburn, G. J. (1993) Continuous Position Measurements and the Quantum Zeno Effect. Physical Review a, 48 1: 132-142. doi:10.1103/PhysRevA.48.132

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Author Gagen, M. J.
Wiseman, H. M.
Milburn, G. J.
Title Continuous Position Measurements and the Quantum Zeno Effect
Journal name Physical Review a   Check publisher's open access policy
ISSN 1050-2947
Publication date 1993-07
Sub-type Article (original research)
DOI 10.1103/PhysRevA.48.132
Open Access Status File (Publisher version)
Volume 48
Issue 1
Start page 132
End page 142
Total pages 11
Place of publication College Park, MD, United States
Publisher American Physical Society
Language eng
Abstract We present a model of continuous (in time) position measurements on a quantum system using a single pseudoclassical meter. The nonselective evolution of the system is described by a master equation which is identical to that obtained from previous models. The selective evolution is described by a stochastic nonlinear Schrödinger equation. The significance of this equation is that the stochastic term has a physical interpretaion. By carefully choosing the parameters which define the meter and the system-meter coupling, we obtain a meter pointer with well-defined position which undergoes fluctuations. This ‘‘jitter’’ in the pointer position gives rise to the stochastic dynamical collapse of the system wave function. By the inclusion of feedback on the meter, the pointer is made to relax towards an appropriate readout. We apply this model to the selective measurement of the position of a particle in a double-well potential. In contrast to a recent claim [H. Fearn and W. E. Lamb, Jr., Phys. Rev. A 46, 1199 (1992)] we show that truly continuous position measurements lead to a quantum Zeno effect in certain parameter regimes. This is manifest by the changing of the particle dynamics from coherent tunneling between the well minima to incoherent flipping, as in a random telegraph. As the measurement strength increases, the average length of time the particle remains stuck in one well increases proportionally.
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Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Engineering Publications
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Citation counts: TR Web of Science Citation Count  Cited 53 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 53 times in Scopus Article | Citations
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