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We present a model of quantum teleportation protocol based on a double quantum dot array. The unknown qubit is encoded using a pair of quantum dots, with one excess electron, coupled by tunneling. It is shown how to create a maximally entangled state using an adiabatically increasing Coulomb repulsion between different dot pairs. This entangled state is exploited to perform teleportation again using an adiabatic coupling between itself and the incoming unknown state. Finally, a sudden separation of Bob’s qubit allows a time evolution of Alice’s which amounts to a modified version of standard Bell measurement. A transmission over a long distance could be obtained by considering the entangled state of a chain of N coupled double quantum dots. The system is shown to be increasingly robust with N against decoherence due to phonons. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

We investigate the role of the noise on the transient dynamics of a simple ecosystem composed of many interacting species. We assume that the species interact randomly. The influence of the environment is modelled by a multiplicative noise. We study the dynamics of the ecosystem for two values of the growth parameter. We obtain the transient and the asymptotic behavior of the average population of the species and the distributions of the population and of the local field. Numerical results are compared with analytical asymptotic behaviors of the time average of the i-th species. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]