Decoherence in the quantum walk on the line

摘要: Abstract We investigate the quantum walk on line when decoherences are introduced either through simultaneous measurements of chirality and particle position, or as a result broken links. Both mechanisms drive system to classical diffusive behavior. In case measurements, we show that diffusion coefficient is proportional variance initially localized random walker just before first measurement. When links between neighboring sites randomly with probability p per unit time, evolution becomes decoherent after characteristic time scales 1 / . The fact quadratic increase eventually lost even for very small frequencies disrupting events suggests implementation real physical may be severely limited by thermal noise lattice imperfections.