18-819E: Special Topics in Applied Physics: Elements of Quantum Communications and Networks
This is an introduction to the building blocks of advanced communication systems and networks based on the principles of quantum mechanics. The kind of information transmitted and processed by this class of systems is of two kinds: discrete and continuous. Discrete quantum information is based on discrete variables exemplified by the quantum bit (qubit). Continuous quantum information is based on continuous variables exemplified by the quantized harmonic oscillator used to define coherent and Gaussian states. As in conventional communication, a quantum communication system has a source, a channel, and a receiver. We will discuss the quantum-optical nature of the building blocks which include single-photon sources and detectors, quantum memory, and quantum interfaces. As the primary quantum object for communications, the photon can take advantage of the quantum resources of superposition and entanglement to offer unprecedented information security not possible in any classical system. There are currently two approaches to implementing quantum communication systems: one is based in fiber-optics and the other on free-space optics. These systems will be analyzed to illustrate use of the building blocks in constructing a practical quantum communication system.
This course is self-contained in that all the essential quantum mechanics required for comprehension of quantum communications is introduced and discussed before it is used.
Last Modified: 2023-07-26 3:27PM
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