Adaptive Phase Measurements

Berry, Dominic William (2001). Adaptive Phase Measurements PhD Thesis, Physics.

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n01front.pdf n01front.pdf application/pdf 120.97KB 2
n02chapter1.pdf n02chapter1.pdf application/pdf 163.46KB 1
n03chapter2.pdf n03chapter2.pdf application/pdf 453.30KB 1
n04chapter3.pdf n04chapter3.pdf application/pdf 476.82KB 1
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n08chapter7.pdf n08chapter7.pdf application/pdf 230.56KB 1
n09chapter8.pdf n09chapter8.pdf application/pdf 89.44KB 1
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n11references.pdf n11references.pdf application/pdf 35.82KB 1
n20020917.pdf Full thesis (author verison) application/pdf 120.97KB 263
Author Berry, Dominic William
Thesis Title Adaptive Phase Measurements
School, Centre or Institute Physics
Publication date 2001
Thesis type PhD Thesis
Supervisor Dr. Howard Wiseman
Abstract/Summary In this thesis I consider the general problem of how to make the best possible phase measurements using feedback. Both the optimum input state and optimum feedback are considered for both single-mode dyne measurements and two-mode interferometric measurements. I derive the optimum input states under general dyne measurements when the mean photon number is fixed, both for general states and squeezed states. I propose a new feedback scheme that introduces far less phase uncertainty than mark II feedback, and is very close to the theoretical limit. I also derive results for the phase variance when there is a time delay in the feedback loop, showing that there is a lower limit to the introduced phase variance, and this is approached quite accurately under some conditions. I derive the optimum input states for interferometry, showing that the phase uncertainty scales as 1/N for all the common measures of uncertainty. This is contrasted with the |j0> state, which does not scale as 1/N for all measures of phase uncertainty. I introduce an adaptive feedback scheme that is very close to optimum, and can give scaling very close to 1/N for the uncertainty. Lastly I consider the case of continuous measurements, for both the dyne and interferometric cases.
Keyword feedback
quantum measurements

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Created: Fri, 21 Nov 2008, 21:39:35 EST