Building Multiple Access Channels with a Single Particle

Building Multiple Access Channels with a Single Particle

Seminar author:Eric Chitambar

Event date and time:02/19/2020 03:00:pm

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A multiple access channel describes a situation in which multiple senders are trying to forward messages to a single receiver using some communication medium. In this talk we consider scenarios in which this medium consists of just a single classical or quantum particle. In the quantum case, the particle can be prepared in a superposition state thereby allowing for a richer family of encoding strategies. To make the comparison between quantum and classical channels precise, we introduce an operational framework in which all possible encoding strategies are restricted to particle number-preserving operations.  We then apply this resource-theoretic framework to an N-port interferometer experiment in which each party controls a path the particle can traverse.  When used for the purpose of communication, this setup embodies a multiple access channel. The channels built from a single classical particle are found to be characterized in terms of second-order coherences, and every quantum resource state in this theory is shown to generate a channel outside the classical set.  We then introduce a notion of a “genuine multiple access channel”, in analog to genuine multipartite entanglement, and we show that an N-local channel generated by a quantum particle can simulate a genuine multiple access channel produced by a classical particle.