Avoiding entanglement sudden death via measurement feedback control in a quantum network
Date
2008-10-31
Authors
Yamamoto, Naoki
Nurdin, Hendra
James, Matthew R
Petersen, Ian
Journal Title
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Publisher
American Physical Society
Abstract
In this paper, we consider a linear quantum network composed of two distantly separated cavities that are
connected via a one-way optical field. When one of the cavities is damped and the other undamped, the overall
cavity state obtains a large amount of entanglement in its quadratures. This entanglement, however, immediately
decays and vanishes in a finite time. That is, entanglement sudden death occurs. We show that the direct
measurement feedback method proposed by Wiseman can avoid this entanglement sudden death, and, further,
enhance the entanglement. It is also shown that the entangled state under feedback control is robust against
signal loss in a realistic detector, indicating the reliability of the proposed direct feedback method in practical
situations.
Description
Keywords
Keywords: Control theory; Feedback control; Quantum optics; Robust control; State feedback; Direct feedbacks; Direct measurements; Entangled states; Finite times; Measurement feedbacks; Optical fields; Quantum networks; Realistic detectors; Signal losses; Sudden de
Citation
Physical Review A 78.4 (2008): 042339/1-11
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Source
Physical Review A: Atomic, Molecular and Optical Physics
Type
Journal article
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DOI
10.1103/PhysRevA.78.042339