2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/91919These notes are more or less a faithful representation of my talk at the Workshop on ``Quantum Coding and Quantum Computing'' held at the University of Virginia. As such it is an introduction for non-physicists to the topics of the quantum theory of light and entangled states of light. In particular, I discuss the photon concept and what is really entangled in an entangled state of light (it is not the photons). Moreover, I discuss an example that highlights the peculiar behavior of entanglement in an infinite-dimensional Hilbert space.5 pages, 1 figure, notes of my talk at the Workshop on ``Quantum Coding and Quantum Computing'' held at the University of VirginiaQuantum Physicstext