Thesis defense of Viviane COTTE

Thesis defense of Viviane COTTE, PhD student in the Quantum Optics group, on Friday 16 December 2022 at 10am in the Auditorium of the Institut d'Optique Graduate School in Palaiseau, on the topic: "Manipulation of light pulses in real time for the generation of quantum states, and study of applications to quantum computing."

Abstract: "This thesis work is about implementing growing protocols using quantum memory cavities to generate complex photonic states and implement quantum operations. A large part of this work focuses on the building up of a high rate source of "optical Schrödinger cat" states (a quantum superposition of two coherent states with opposite phases). These states underlie multiple protocols in quantum information and calculus (some of them are presented in this thesis). This is the reason why the development of such reliable and quick sources is so interesting.

We present here a first experiment, using our growing protocol, leading to the generation of such states with a high production rate, easily improvable for reaching the order of ten of kilohertz. Furthermore, we stored the generated states in a quantum memory, which is a world's first. This could lead to future experiments, such as the generation of more complex states or the realization of quantum information/calculus protocols (especially protocols based on continuous variables).

This experiment involves a single photon pair source (generation through optical parametric fluorescence), a quantum memory cavity with a storage/extraction system, a phase measurement path, and a homodyne detection system. We present here the various results and improvements implemented during the thesis. We also propose possible evolutions of this experiment to reach its theoretical limit. Doing so is a first step toward implementing an all-optical quantum processor."