Marches aléatoires quantiques dans les milieux désordonnés

Abstract

Light is not only an ideal medium to transmit information, but also a very interesting physical system to process it. In this respect, quantum optics has recently emerged as a highly promising domain for the development of new computing applications that can surpass the performances of currently available systems. In this respect, quantum walk of photons has recently emerged as a very powerful model for quantum information science, and integrated photonic devices have proven a versatile architecture for their implementation. While these waveguide structures allow only near-neighbor coupling between up to a few tens of modes, complex linear systems, such as white paint layer or multimode fiber, enable to couple efficiently a huge numbers of optical modes. Unstable and lossy, these systems have always been considered unpractical for quantum optics experiments. Wavefront shaping methods, developed in the last decade to control light propagating in complex media, allow moving beyond these limitations and make them exploitable with non-classical light. In our work, we demonstrate the implementation of quantum walks in a layer of paint and a multimode fiber using single-photons and photon-pairs. For this purpose, we extend wavefront shaping methods, originally developed to control classical light propagation in complex media, to non-classical light. This capability to manipulate photons allows building new controllable highly multimode optical platforms. Such systems pave the way for the next generation of quantum information processing devices.