Processing Applications of Multiple Quantum Teleportation and Structured Light Beams

Abstract

This dissertation project was designed to work in parallel with the theoretical development of parallel quantum teleportation applications and with the experimental study of structured light beams and their potential application to communications. The study of quantum teleportation has become popular over the years since it was first described by Charles Bennett and his colleagues in the early 1990s. Since then, many processes have emerged for the improvement of the fidelity and exciting applications have arisen, such as those aimed to enhance communication systems. This dissertation explores the development of a scheme for parallel quantum teleportation, starting with the analysis of a double teleportation, where an unknown quantum state is intended to be teleported to two simultaneous receivers, and extending such analysis so that the state is quantumly transmitted in superposition to several receivers supported by other quantum states used as a control. This studied scheme is used for the development of some applications such as for cryptography purposes in the settlement of secure authentication, in Quantum Key Distribution, Quantum Parameter Estimation and database settlement. In these applications, it is highlighted the use of the parallel quantum teleportation for carrying out the process or for some specific stages along the process. Jointly with the theoretical work, the experimental development for structure light applications was made in terms of the study of properties of some vortex beams, such as the Laguerre-Gaussian, Hermite-Gaussian and Bessel beams and their behaviour when the source light is partially coherent, which brings critical advantages against noise and turbulence in the environment but, however, it has the downside to be hard to identify the intensity profile. For this reason, a scheme for characterizing these Partially Coherent Beams as well as the possible effects of turbulence was studied in this work. Finally, a study of the application of entangled photons for learning the phase of unknown unitary operations was also experimentally tested. This document, also presents a proposal for an experimental implementation of parallel double teleportation for communication, involving Structured Light Beams.