20 research outputs found
Control of Optical Dynamic Memory Capacity of an Atomic Bose-Einstein Condensate
Light storage in an atomic Bose-Einstein condensate is one of the most
practical usage of these coherent atom-optical systems. In order to make them
even more practical, it is necessary to enhance our ability to inject multiple
pulses into the condensate. In this paper, we report that dispersion of pulses
injected into the condensate can be compensated by optical nonlinearity. In
addition, we will present a brief review of our earlier results in which
enhancement of light storage capacity is accomplished by utilizing multi-mode
light propagation or choosing an optimal set of experimental parameters.Comment: 4 figures, 11 page
Decoherence in Two-Dimensional Quantum Random Walks with Traps
Quantum random walk in a two-dimensional lattice with randomly distributed
traps is investigated. Distributions of quantum walkers are evaluated
dynamically for the cases of Hadamard, Fourier, and Grover coins, and quantum
to classical transition is examined as a function of the density of the traps.
It is shown that traps act as a serious and additional source of quantum
decoherence. Furthermore, non-trivial temporal dependence of the standard
deviation of the probability distribution of the walker is found when the
trapping imperfections are introduced.Comment: 7 pages, 9 figure