Date of Award

9-2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Engineering Physics

First Advisor

Anil K. Patnaik, PhD

Abstract

Free-space quantum networks can enable global-scale quantum communication via satellite-based nodes and quantum ground transceivers. To enable building of robust global quantum networks, it is critical to learn how the state of the qubit is transformed while propagating through the atmosphere. With such an overarching goal, we built a laboratory based atmospheric turbulence simulator (ATS) to characterize the effects of atmospheric turbulence on an entangled pair of photons as a function of statistical quantities such as the Fried parameter or scintillation index for long-distance communication. Specifically, the changes in the statistical properties associated with a quantum source was investigated using the Hanbury Brown-Twiss correlations. Due to the design of our ATS, we are also in a position to study the degradation of the indistinguishability between photons Hong-Ou-Mandel correlations for future work. A theoretical model describing quantum states of light propagating through the atmosphere has been developed earlier by other authors. The Glauber-Sudarshan P function was considered to represent the qubit state, and the output states were evaluated by employing a linear attenuator with a randomly varying transmission coefficient to describe atmospheric effects. In collaboration with AFRL/RDS, experimental data was collected at a 1 mile field site at the Starfire Optical Range to calculate probability distributions of the transmission coefficient and to compare with theoretical models. The outcome of the laboratory and field experiments provided crucial information regarding the parameter space for high fidelity qubit propagation through the atmosphere and enable the development of a robust quantum network.

AFIT Designator

AFIT-ENP-DS-23-S-011

Comments

88ABW 2023-0741

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