Quantum Walks in Periodic and Quasiperiodic Fibonacci Fibers.

Quantum walk is a key operation in quantum computing, simulation, communication and information. Here, we report for the first time the demonstration of quantum walks and localized quantum walks in a new type of optical fibers having a ring of cores constructed with both periodic and quasiperiodic Fibonacci sequences, respectively. Good agreement between theoretical and experimental results has been achieved.

Localized quantum walks in quasi-periodic Fibonacci arrays of waveguides.

New quasi-periodic arrays of waveguides (AWs) constructed with Fibonacci sequences are proposed to realize localized quantum walks (LQWs). The proposed Fibonacci arrays of waveguides (FAWs) are simple and straightforward to make, but have a rich set of properties that are of potential use for applications in quantum communication. Our simulations show that, in contrast with randomly disordered AWs, LQWs in FAWs are highly controllable due to the deterministic disorder nature of quasi-periodic systems.

Electron injection from colloidal PbS quantum dots into titanium dioxide nanoparticles.

Injection of photoexcited electrons from colloidal PbS quantum dots into TiO(2) nanoparticles is investigated. The electron affinity and ionization potential of PbS quantum dots, inferred from cyclic voltammetry measurements, show strong size dependence due to quantum confinement. On the basis of the measured energy levels, photoexcited electrons should transfer efficiently from the quantum dots into TiO(2) only for quantum-dot diameter below approximately 4.

Low-loss hollow-core silica/air photonic bandgap fibre.

Photonic bandgap structures use the principle of interference to reflect radiation. Reflection from photonic bandgap structures has been demonstrated in one, two and three dimensions and various applications have been proposed. Early work in hollow-core photonic bandgap fibre technology used a hexagonal structure surrounding the air core; this fibre was the first demonstration of light guided inside an air core of a photonic bandgap fibre.