University of Illinois Urbana-Champaign

Applications of entanglement at extreme distance scales

Johnson, Spencer James

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https://hdl.handle.net/2142/125691

Description

Title
Applications of entanglement at extreme distance scales
Author(s)
Johnson, Spencer James
Issue Date
2024-07-08
Director of Research (if dissertation) or Advisor (if thesis)
Kwiat, Paul
Doctoral Committee Chair(s)
Lorenz, Virginia
Committee Member(s)
  • Chitambar, Eric
  • Backlund, Mikael
Department of Study
Physics
Discipline
Physics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • Quantum Information
  • Quantum Optics
  • Entanglement
  • Quantum Sensing
  • Quantum Networking
Abstract
Entanglement, a unique feature of quantum mechanics in which two particles share correlations beyond what is possible classically, can be exploited for gains in sensing, communication, and computation. It can be used to connect quantum computers and sensors on a global scale and beyond, or for better sensing of the most sensitive phenomena. Here we will explore three such applications of entangled photons across a range of distance scales: First, a sensor which utilizes frequency entanglement to measure nanometer-scale displacements and vibrations with orders of magnitude fewer resources than traditional quantum approaches. We perform a theoretical study of noise in interferometry, comparing the effects of common noise sources on classical interference, degenerate two-photon interference, and frequency-entangled two-photon interference. We then construct a component-based noise model of such a frequency-entangled interferometer, which is used to predict performance of our experimental system based on real-world optics. Our experimental implementation of such an interferometer, utilizing frequency-entangled photon pairs at 810 nm and 1550 nm, is demonstrated to have two-photon interference visibility > 0.89, corresponding to a 88.6% saturation of the Quantum Cramér-Rao bound when used for metrology. Second, we present a theoretical model for noisy fiber- and space-based quantum networks, used to optimize network rates for inter/trans continental entanglement distribution. We study the effects of noise on swapping rates and finalized state quality, comparing different source technologies, detection methods, and link architectures. Finally, we discuss efforts to create a compact postselected entanglement source and integrated tomography system suitable for a space environment. Using a novel quantum-state tomography system consisting of only a single liquid crystal variable retarder per photon, we characterize the source, demonstrating entanglement fidelities in excess of 99%.
Graduation Semester
2024-08
Type of Resource
Thesis
Handle URL
https://hdl.handle.net/2142/125691
Copyright and License Information
Copyright 2024 Spencer Johnson

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