Marquardt C (2007)
Publication Type: Thesis
Publication year: 2007
Publisher: DAI-B 82/12(E), Dissertation Abstracts International
City/Town: Ann Arbor, United States
ISBN: 9798744484118
URI: https://opus4.kobv.de/opus4-fau/frontdoor/index/index/docId/555
The aim of this thesis was the characterization of continuous variable quantum states of light and their application in quantum information processing protocols. The photo current statistics of squeezed and entangled states from a nonlinear fiber Sagnac interferometer were analyzed and can be regarded as Gaussian states within the measurement accuracy. In addition, instead of the usual variance, the covariance was experimentally investigated as a relative measure of squeezing, using a balanced self-homodyne system. As an application in a quantum information protocol the experimental distillation of squeezed states has been shown. The undistilled squeezed states suffered from non-Gaussian classical excess noise. In the experiment nearly the complete squeezing could be recovered by a probabilistic selection method. The Cavalcanti-Reid criterion to prove intrinsic macroscopic superposition states in continuous variables was experimentally applied for the first time. With this criterion generalized superposition states were proven in vacuum and intense coherent states with a distance in phase space of 0.51+/-0.02 shot noise units. For squeezed states from an optical parametric oscillator generalized superposition states were proven with a distance of up to 0.83+/-0.02 shot noise units. At the same time the dependence of the criterion on squeezing and purity of the states was investigated. To reconstruct the quantum state of the polarization variables of light, a theory was developed, that is based on the su(2) algebra and at the same time takes into account the possibility, that the photon number is not fixed. It was found that for high photon numbers the quantum state reconstruction of the SU(2) Q function in Poincare space is an inverse 3D Radon transformation. With this method the Q function of a polarization squeezed state was reconstructed from measured data. In the dark plane of a polarization squeezed state the Wigner function of an intense Kerr squeezed state was reconstructed for the first time.
APA:
Marquardt, C. (2007). Characterization and application of continuous variable quantum states of light (Dissertation).
MLA:
Marquardt, Christoph. Characterization and application of continuous variable quantum states of light. Dissertation, Ann Arbor, United States: DAI-B 82/12(E), Dissertation Abstracts International, 2007.
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