Quantum Walks

Quantum walks constitute a universal model platform exploited frequently for studies of particle spreading in media incorporating different types of geometries, temporally changing connectivity or different sources of defects. Quantum wave representing a particle’s occurence probability in space is repeatedly splitted in order to interfere again the very next moment. The interference may induce a speedup of wave’s spreading or, on the contrary, its complete stopping and incidental phenomena, which we do not observe in classical physics. The situation becomes even more interesting if there are more particles in the medium, which may interact with each other. Within this topic an excitation transport is studied, its speed and efficiency, how it depends on the geometry and other parameters of the system, what correlations arise among particles and how they influence the overall efficiency.